2004 memoria

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

MEMÒRIA ANUAL Exercici 2004

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació Índice Memoria 2004 Presentación 1. Tesis de Doctorado 2. Trabajos de investigación Máster l l

2.1. Máster de segmento anterior, parte I & parte II 2.2. Máster de segmento posterior

3. Líneas de investigación en desarrollo l

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3.1. Proyecto Unión Europea: Importancia de la sensibilidad al deslumbramiento y de los trastornos de la función visual en los conductores europeos ¡ 3.1.1. Centros participantes ¡ 3.1.2. Reunión de los centros en Barcelona 29 de noviembre 2004 ¡ 3.1.3. Primeros resultados 3.2. Proyecto Phaco Ersatz: Reemplazamiento del material cristaliniano para recuperar la acomodación tras la cirugía de cataratas ¡ 3.2.1. Construcción de un aparato para simular la acomodación ex vivo ¡ 3.2.2. Revisión de los métodos actuales para evitar la opacificación de la cápsula posterior después de la cirugía de la catarata ¡ 3.2.3. Pruebas actuales para la medición objetiva de la acomodación: estudio bibliográfico ¡ 3.2.4. Medición del espesor de la cápsula del cristalino 3.3. Seguridad de la iluminación de los microscopios quirúrgicos

4. Actividades docentes l l

4.1. Transparency Club 4.2. Actividades en European Association for Vision and Eye Research ¡ 4.2.1. Organización y moderación de un Special Interest Symposium durante el congreso EVER 2004: parte I & parte II

5. Publicaciones 6. Apéndice l l

6.1. Propuesta de actividades 2005 6.2. Próximas líneas de investigación

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

PRESENTACIÓN

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

Presentació Em complau poder presentar, per primera vegada des de la seva constitució, una Memòria anual de l'activitat de la Càtedra de resultats efectius, és a dir, de projectes que han assolit un grau de desenvolupament molt avançat o complet.

La investigació sobre "La visió dels conductors europeus", que s'ha realitzat al llarg d'aquest any, ha presentat ja l'informe de resultats preliminars. Ara, durant el 2005, aprofundirem mitjançant un estudi d'avaluació d'aquests resultats, per al qual hem estat designats per la Unió Europea. La nostra participació ha inclòs l'estudi de 346 conductors voluntaris i la organització de la Reunió d'investigadors participants el proppassat dia 26 de novembre.

També ha estat moment de resultats en la investigació portada a terme en col.laboració amb el Departament d'Oftalmologia de la Rheinische Friedrich-Wilhelms Universität (Bonn-Alemanya) i la Companyia ZEISS, sobre "l'estudi de la seguretat en l'ús de la llum ultraviolada en els microscopis quirúrgics" els resultats de la qual han estat publicats en el Journal of the Optical Society of America.

Dintre del projecte Phaco Ersatz, hem pogut desenvolupar un sofisticat instrument que ens permetrà mesurar la tensió necessària i el desplaçament aconseguit en la tracció exercida sobre el cristal.lí pel múscul ciliar.

Per últim, en el congrés anual d'investigadors EVER, a on el nostre Coordinador d'investigació el Dr. R. Michael ha estrenat el seu càrrec com a Membre electe del Comitè Directiu, hem tingut la responsabilitat d'organitzar i dirigir el "Special Interest Symposium about Accommodative intraocular lenses".

Dr. Rafael I. Barraquer 2.II.05

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

1. TESIS DE DOCTORADO

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

1. Tesis de doctorado en desarrollo Astigmatismo inducido en la cirugía de la catarata con pequeña incisión.

Dr. Andrés Picó García, Centro de Oftalmología Barraquer Evolución del astigmatismo a largo plazo tras queratoplastia penetrante en queratocono.

Dr. Juan P. Alvarez de Toledo Elizalde, Centro de Oftalmología Barraquer Resultados funcionales de la fotocoagulación láser mediante rejilla del edema macular diabético difuso.

Dr. Jerónimo Nadal Reus, Centro de Oftalmología Barraquer Lentes precristalinianas para la corrección de alta miopía.

Dr. Tahsin Martini, Hospital Martini, Aleppo, SIRIA Tutor: Prof. Joaquín Barraquer, Centro de Oftalmología Barraquer

Endoftalmitis de etiología exogena. Revisión de datos clínicos.

Dra. Simona Nossa, Bergamo, ITALIA Tutor: Dr. Santos Muiños, Centro de Oftalmología Barraquer

Influence of exposure patterns in UVR-induced cataract.

Dr. Marcelo Ayala, Örebro University Hospital, Örebro, SUECIA Lectura: 20 de Mayo 2005 Tutor: Prof. Per Söderberg, Karolinska Institutet; Dr. Ralph Michael, Institut Universitari Barraquer

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Influence of exposure patterns in UVR-induced cataract.

PhD thesis Marcelo Ayala Örebro University Hospital, Eye Department, Örebro, Sweden St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden Tutors: Prof. Per Söderberg, St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden Dr. Ralph Michael, Institut Universitari Barraquer, Barcelona, Spain PhD defense scheduled for 20. May 2005 in Örebro, Sweden Ayala MN, Michael R, Soderberg PG. Influence of exposure time for UV radiation-induced cataract.

Invest Ophthalmol Vis Sci. 2000 Oct;41(11):3539-43.

St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden.

Ayala MN, Michael R, Soderberg PG. In vivo cataract after repeated exposure to ultraviolet radiation.

Exp Eye Res. 2000 Apr;70(4):451-6.

St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden.

Marcelo N Ayala (1,2), Per G Söderberg (2) Vitamin E can protect against ultraviolet radiation-induced cataract in albino rats.

Ophthalmic Res 2004;36: 1) Örebro University Hospital, Eye Department, Örebro, Sweden 2) St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden Marcelo N Ayala (1,2), Per G Söderberg (2) Reversal of reciprocity law failure for UVR-induced cataract with vitamin-E. Manuscript.

1) Örebro University Hospital, Eye Department, Örebro, Sweden 2) St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden M. Ayala (1,3), H. Strid (2), U. Jacobsson (2), X. Dong (3), P. G. Söderberg (3).

P53 expression in the lens after ultraviolet radiation (UVR) exposure.

Manuscript.

1) Eye Department, Örebro University Hospital, Örebro, Sweden.

2) Clinic Research Centre, Örebro University Hospital, Örebro, Sweden.

3) St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden.

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

2. TRABAJOS DE INVESTIGACIÓN MÁSTER

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

2. Trabajos de investigación Máster 2.1. Master de segmento anterior 2003-2004 - Trabajos de investigacion, parte I NOMBRE

TÍTULO

COORDINADOR

DR. ABREU

Human lens capsule thickness as function of age Dr. Rafael I. Barraquer and location along the saggital lens border Dr. Ralph Michael

DR. ARTEAGA

Técnicas de cálculo de LIO en pacientes con Dr. Álvarez de Toledo cirugía refractiva previa

DR. ALVARADO DR. MATOS DR. BOLEAS DR. BUCHACRA

Trabreculectomía versus esclerectomía profunda Dra. I. Canut no perforante

DR. FARIÑA DR. BURGOS

Farmacología en el glaucoma

Dra. I. Canut

DRA. CRUZ

Uveítis y enfermedades sistémicas

Dr. R. Escoto

DRA. GARASSINO

Malignización de lesiones pigmentarias iridianas Dr. Elizalde

DR. CAMILION DRA. PALAVECINO

(con dra. Nikolic)

DRA. GIAGANTE DRA. GARRIDO DRA. REGALADO DRA. JIMENEZ DRA. RENDÓN

Correlación entre los hallazgos clínicosy Dr. F. Ruiz Tolosa herramientas diagnósticas: Gdx, HrtII, campo visual en pacientes con sospecha de glaucoma Extracción de cristalino transparente como Dr. Álvarez de Toledo tratamiento refractivo. Indicaciones, resultados y complicaciones

DRA. ROMERO DR. LAMARCA DRA. SEMPERE Home: www.catedrabarraquer.org Página actualizada: 25 febrero 2005

Revisión de los métodos actuales para evitar la Dr. R.I. Barraquer opacificación de la cápsula posterior después de Dr. R. Michael la cirugía de la catarata

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

2. Trabajos de investigación Máster 2.1. Master de segmento anterior 2003-2004 - Trabajos de investigacion, parte II NOMBRE

TÍTULO

COORDINADOR

DRA. LEMMA

Il glaucoma a pressione normale: aspetti diagnostici e terapeutici

DRA. NIKOLIC

Quistes y tumores del iris no pigmentados (y c. Dr. Temprano Ciliar) Dr. Barraquer (En conjunto con los dres. Garassino, Camilion, Dr. Ruiz Bulumar Palavecino y Giagante) Dr. Elizalde

DR. NORMAND

Estudio comparativo restrospectivo del control Dra. MI. Canut tensional y las complicaciones secundarias a sonofacoextracción asociada a trabeculectomía en diabéticos versus no diabéticos

DRA. PASCUAL

Pruebas actuales para la medición objetiva de la Dr. Rafael I. Barraquer acomodación: estudio bibliográfico Dr. Ralph Michael

DRA. DELA PAZ

Efecto de a lente amarilla (Acrysof Nature) en la Dr. Rafael I. Barraquer visión

DR. RODRIGUEZ

Posibles proyectos de investigación. Máster en Dr. García Barberán segmento anterior II: Catarata y glaucoma

DRA. SANDOVAL

Cirugía de catarata en pacientes con retinopatía Dr. R. Escoto diabética: resultados visuales

DR. ZKERT

Técnicas de fijación del LIO en cámara posterior Dr. R. Escoto en ausencia de soporte capsular Dr. Pesic

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Dr. García Barberán

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

2. Trabajos de investigación Máster 2.2. Master de segmento posterior 2003-2004 - Trabajos de investigacion NOMBRE DR. ABREU DRA. SEMPERE DR. ARTEAGA DRA. IZDEBSKA DR. BUCHACRA DR. PIÑEIRO

TÍTULO

COORDINADOR

Valoración de la eficacia a largo plazo de la Dr. J. Nadal fotocoagulación como tratamiento de la epiteliopatía difusa Pérdida de la agudeza visual y campo visual en Dr. S.J. Muiños la retinitis pigmentaria. Análisis de las enfermedades coexistentes Lesiones predisponentes y no predisponentes de Dr. S. Abengoechea DR regmatógeno. Revisión Bibliográfica

DR. FARIÑA DR. BURGOS

Membranas neovasculares coroideas. Revisión Dr. R. Escoto bibliográfica

DR. CAMILION

Uso de aceite de silicona como taponador en Dr. J. Elizalde cirugía vitreoretiniana

DRA. GARASSINO

DRA. GIAGANTE DRA. PALAVECINO DRA. CARRERAS

Enfoque terapéutico del edema macular difuso Dr. J. Nadal diabético

DRA. CRUZ

Enfermedades del pacientes con SIDA

DR. LAMARCA

Triamcinolona intravitrea: indicaciones actuales Dr. J. Elizalde para su uso

DR. MONTARULI

Diabetic retinopathy: photocoagulation

DR. NORMAND

Utilidad de la OCT en el diagnóstico , decisión Dr. S. Abengoechea terapéutica y seguimiento postoperatorio de los síndromes de tracción vitreorretiniana

DRA. PASCUAL

Estudio comparativo entre diferentes Dr. R. Escoto tratamientos para el edema macular diabético

DR. POPOSKI

Tratamiento fotodinámico en la salud pública

DRA. RENDÓN

Oclusiones vasculares venosas (isquémicas vs Dr. J. Nadal no isquémicas)

DR. ZKERT

Complicaciones más frecuentes durante las Dr. S. Abengoechea operaciones del segmento posterior

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segmento

posterior

Argon

en Dr. R. Escoto

laser Dr. S.J. Muiños

Dr. R. Escoto

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

3. LÍNEAS DE INVESTIGACIÓN EN DESARROLLO

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

3. Líneas de investigación en desarrollo 3.1. Proyecto Unión Europea: Importancia de la sensibilidad al deslumbramiento y de los trastornos de la función visual en los conductores europeos - Propósito y Métodos R. Michael, M. Alvarez Fischer, J. Gálvez, M. Aguiló, L. Garassino, R. I. Barraquer Institut Universitari Barraquer en cooperación con: T.J.T.P. van den Berg, The Netherlands Ophthalmic Research Institute, Amsterdam, Holanda; L.J. van Rijn, Vrije Universiteit Medical Center, Dept. of Ophthalmology, Amsterdam, Holanda; G. Grabner, Landesklinik für Augenheilkunde, St. Johanns-Spital, Salzburg, Austria; H. Wilhelm, Universitäts-Augenklinik, Universität Tübingen, Tübingen, Alemania T. Coeckelbergh, Universitair Ziekenhuis Antwerpen, Antwerpen, Bélgica Propósito: Determinar la importancia prevaleciente de los trastornos de la función visual en los conductores de edad avanzada en los países europeos. Para este propósito se van a investigar las siguientes áreas: la agudeza visual, la sensibilidad al contraste, la luz dispersa en el ojo, el campo visual, el campo visual útil, la información complementaria con ayuda de dos cuestionarios, y la clasificación del cristalino según el sistema de LOCS III (catarata). Este proyecto internacional de investigación está financiado parcialmente por la Unión Europea con número de proyecto: SUBB27020-E3-GLARE-2002-S07.18091. El proyecto se inició el 1 de enero del 2003 y tiene una duracion de dos años. (www.glare.be) Objetivos: Se determinará la frecuencia de los tipos más importantes de trastornos visuales en los conductores europeos. Las tres funciones visuales de principal interés son: la agudeza visual (la capacidad de distinguir pequeños detalles), el campo visual (las capacidad de ver las cosas en las áreas laterales), y la sensibilidad al deslumbramiento (el grado de disminución visual en caso de exposición a una luz fuerte en la periferia, sol en posición baja o, por la noche, los faros de los coches que vienen de frente). Estas funciones visuales, en particular la sensibilidad al deslumbramiento, sufren un declive con la edad. Para decidir qué funciones visuales específicas para la concesión del permiso de conducir son importantes es necesario determinar la importancia prevaleciente de la disminución de la función visual en función de la edad. Actualmente no existen exigencias oficiales respecto a la sensibilidad al deslumbramiento de los conductores, aunque se admite generalmente como factor importante para la seguridad del tráfico. La razón es que no existe ningún valor estándar para ello.

Métodos previstos: Los grupos incluidos en las pruebas: Población de conductores mayores de un área seleccionada en grupos divididos por edades: (45-54, 55-64, 65-74 y 75-84). En cada grupo de edad se incluye un número aproximadamente igual de participantes. Por lo tanto habrá 4 grupos, con 140 participantes por grupo en cada localización, así el número total de participantes es de 560.

(En total en 4 localizaciones: 2240 participantes). Además: por cada localización se incluyen 40 participantes entre 20 y 30 años de edad, sin anormalidades oculares, sanos, para constituir un grupo de control para los resultados de la prueba.

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EU project: SUB-B27020B-E3-GLARE-2002-S07.18091

Relevance of glare sensitivity and impairment of visual function among European drivers

Netherlands Ophthalmic Research Institute

The Netherlands

The Netherlands

Austria

Belgium

Spain

Germany

Contact information and involved institutes Grant holder: The Netherlands Ophthalmic Research Institute (NORI) of The Royal Netherlands Academy of Arts and Sciences Dr. P van ‘t Klooster, director CW van Leeuwen, administrative officer

Project leaders and contact persons:

Dr. T.J.T.P. van den Berg and Dr. L.J. van Rijn Meibergdreef 47 1105 BA Amsterdam The Netherlands Tel. (+31)20-5665185 Fax. (+31)20-5666121 E-mail: T.J.vandenBerg@ioi.knaw.nl vanRijn@vumc.nl

Involved institutes: Netherlands Ophthalmic Research Institute Contact information: see above Landesklinik für Augenheilkunde und Optometrie Prof. Dr. G. Grabner St. Johanns-Spital Müllner Hauptstraße 48 A-5020 Salzburg Austria Vrije Universiteit Medical Center, Department of Ophthalmology Dr L.J. van Rijn PO Box 7057 NL-1007 MB Amsterdam The Netherlands

Centro de Oftalmología Barraquer Càtedra de Recerca en Oftalmologia J. Barraquer Dr. R.I. Barraquer and Dr. R. Michael Muntaner, 314 E-08021 Barcelona Spain

Universitäts-Augenklinik Prof. Dr. H. Wilhelm Schleichstraße 12-16 D-72076 Tübingen Germany

Universitair Ziekenhuis Antwerpen Dr. T. Coeckelbergh Wilrijkstraat 10 2650 Edegem Belgium 2

Persons involved in the project Netherlands Ophthalmic Research Institute (Amsterdam) Dr. T.J.T.P. van den Berg local and overall project leader Dr. G.C. de Wit project coordinator, researcher J.E. Coppens senior researcher L. Franssen researcher Vrije Universiteit Medical Center (Amsterdam) Dr L.J. van Rijn, ophthalmologist, local and overall project leader Prof dr H.J. Völker-Dieben, ophthalmologist E. Gutker, ophthalmic nurse R. Kaper, ophthalmic assistant D.J. Vonhoff, ophthalmic assistant F. Huizing-Chapel, ophthalmic assistant D. Dijkstra (van Hellemond) recruitment Staff opthalmologists and residents Co-workers outpatient department Centro de Oftalmología Barraquer (Barcelona) Dr. R.I. Barraquer, director Centro de Oftalmología Barraquer Dr. R. Michael, local project leader M. Alvarez Fischer, ophthalmologist J. Gálvez, optometrist, head optometry dept.

M. Aguiló, optometrist, head visual field dept.

V. Rojo, optometrist L. Garassino, ophthalmologist Universitair Ziekenhuis Antwerpen (Antwerpen) Prof. dr. M.J. Tassignon, head of the department Dr. T. Coeckelbergh, local project leader Dr. K. Verbruggen, ophthalmology resident Dr. D. Verhelst, ophthalmology resident Dr. S. Ceuterick, ophthalmology resident Dr. J. Van Looveren, ophthalmology resident Dr. B. Reyntjens, ophthalmology resident Dr. P. Schraepen, ophthalmology resident Dr. S. Kiekens, ophthalmology resident Dr. K. Mgaieth, ophthalmology resident D. Godts, orthoptist C. Ferdinandus, nurse G. Vandeweyer, nurse B. Swenters, nurse

3

Landesklinik f체r Augenheilkunde und Optometrie (Salzburg) Prof. dr. G. Grabner ophthalmologist, local project leader Dr. M. Emesz ophthalmologist Dr. P. Marvan ophthalmologist in training Dr. N. Nischler ophthalmologist in training Dr. Ch. Hufnagl ophthalmologist in training Universit채ts-Augenklinik (T체bingen) Prof. Dr. med. H. Wilhelm Dr. med. C. Heine B. Meyer Cand. med . B. Matthiesen Cand.med. B. Voykov Cand. med E. Guenova stud. med. A. Kasperkowiak G. Wilhelm I. Mildenberger A. Ene Cand. med. M. Sell

ophthalmologist, local project leader resident ophthalmology ophthalmic assistant, optician student, assistant student, assistant student, assistant student, assistant student, assistant student, assistant student, assistant student, assistant

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació 3.1. Proyecto Unión Europea 3.1.2. Reunión de los centros que colaboraron en el estudio europeo sobre los conductores.

Barcelona, 29 de noviembre 2004 Orden del día l l l

9.30 9.45 10.15 ¡

l l l l

11.00 11.15 13.30 14.30 ¡ ¡ ¡

l

18.30

Opening of the meeting Further results from Amsterdam (van Rijn) Development of straylight meter (group vd Berg) Analysis of straylight data (group vd Berg) Coffee break Contributions from each participating centre Lunch outside in a restaurant Discussions Aspects for analysis of data How to analyse visual fields Distribution of topics to be analysed Closure

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació 3.1. Proyecto Unión Europea 3.1.3. Importancia de la sensibilidad al deslumbramiento y de los trastornos de la función visual en los conductores europeos - Primeros resultados Ralph Michael, Marco Alvarez Fischer, Jose Gálvez, Manel Aguiló, Laura Garassino, Andres Pico, Rafael I. Barraquer Institut Universitari Barraquer En este estudio realizado durante el año 2004 participaron unos 2422 conductores de edad avanzada en los centros colaboradores en Amsterdam, Antwerpen (Amberes), Salzburg, Tübingen y Barcelona. En Barcelona participaron 346 conductores, que vinieron a través de familiares y amigos del personal del Centro de Oftalmología Barraquer y otros seleccionados aleatoriamente de miembros del RACC Automóvil Club.

Resultados: La prevalencia de la agudeza visual deteriorada es de 0.9% en el grupo de 45-54 años y sube hasta 5.3% en el grupo de 75-84 años con sus gafas habituales. Son conductores que no cumplen los estándares europeos actuales para el permiso de conducir, que requiere una agudeza visual de 0.5 en el mejor ojo. En la mayoría de estos casos de agudeza visual deteriorada, una agudeza visual de 0.5 o superior se puede alcanzar con la corrección apropiada del error refractivo.

En un 10.2% de todos los conductores la agudeza visual se puede mejorar 2 líneas o más con la mejor corrección de sus gafas.

La prevalencia del campo visual defectuoso es de 0.5% en el grupo de 45-54 años y 2.7% en el grupo de 75-84 años. Son conductores que no cumplen los estándares europeos actuales para el permiso de conducir que requiere una extensión horizontal del campo visual de 120 grados. La prevalencia de la sensibilidad al contraste deteriorada es de 0.2% en el grupo de 45-54 años y sube hasta 6.3% en el grupo de 75-84 años. Se ha considerado valores por debajo de 1.25 en la tabla de Pelli-Robson como deteriorados. Actualmente no hay estándares europeos para los conductores con respecto a la sensibilidad al contraste.

La prevalencia de valores altos de luz dispersa en el ojo son un 0.8% en el grupo de 45-54 años y 29.5% en el grupo de 75-84 años. Se ha considerado valores sobre 1.4 en el Stray light meter como deteriorados. Actualmente no existen exigencias oficiales respecto a la luz dispersa en el ojo. La prevalencia de la catarata clínicamente relevante es de un 14% en el grupo de 75-84 años. Un 23.7% de este grupo han sido operados de cataratas.

Un 12% de todos los conductores del estudio tiene antecedentes de accidentes de tráfico en los últimos 3 años. Sin embargo, no hemos encontrado ninguna relación entre trastornos visuales y accidentes de tráfico en el grupo estudiado. La diferencia entre el promedio de la edad de conductores con y sin accidentes es insignificativo como también la diferencia entre el promedio de la suma de kilómetros conducidos de conductores con y sin accidentes. Conductores que admiten una mayor velocidad de conducir (en comparación con los demás) tienen mejores funciones visuales. Hemos descubierto que las personas de edad avanzada, que sufren cambios en la función visual, aparentemente reconocen sus limitaciones y se ponen autolimitaciones en su conducción.

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

3. Líneas de investigación en desarrollo 3.2. Proyecto Phaco Ersatz: Reemplazo del material cristaliniano para recuperar la acomodación tras cirugía de cataratas Ralph Michael, Rodolfo Carretié, Rafael I. Barraquer Institut Universitari Barraquer Objetivo: Con la edad el cristalino tiende a perder flexibilidad y gradualmente se hace más opaco.

Cuando los opacidades han aumentado y disminuyen la visión se habla de catarata. Su tratamiento actual consiste en retirar el material opacificado y reemplazarlo por una lente artificial y rígida. La pérdida de la flexibilidad del cristalino es la causa de la presbicia que está presente en todas las personas mayores de 40 años. Este síntoma se manifesta a través de la disminución de la capacidad de enfocar (la acomodación). De momento no hay tratamiento para la presbicia. La nueva estrategia de la operación de catarata sería retirar el material alterado de la cápsula cristaliniana manteniendo esta estructura intacta, y sustituirlo por un gel flexible que se inyectaría dentro de la cápsula vacía.

Con este método se puede no solamente recuperar la visión, sino también la acomodación.

Métodos: El proyecto exige el estudio de la anatomía del segmento anterior del ojo, especialmente, la cápsula del cristalino, sus propiedades mecánicas, la zónula, el cuerpo ciliar y la coroides. Hay que estudiar y evaluar las diferentes teorías de la acomodación que existen. Para el éxito del proyecto hay que desarrollar las técnicas de la cirugía de catarata a través de una incisión muy pequeña y hay que encontrar una solución de la opacificación capsular posterior. Hay que buscar un nuevo material similar a un gel con unas propiedades mecánicas similares a la del cristalino que podría ser utilizado para reemplazar el contenido del cristalino.

Figure: from Parel, J M. Gelender, H. Trefers, W F. Norton, E W. Phaco-Ersatz: cataract surgery designed to preserve accommodation. Graefes Arch.

Clin. Exp. Ophthalmol.1986 (224(2)) pp 165-173.

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació 3.2. Proyecto Phaco Ersatz 3.2.1. Construcción de un aparato para simular la acomodación ex vivo Ralph Michael, Rodolfo Carretié, Rafael I. Barraquer Institut Universitari Barraquer Hemos diseñado un aparato para medir las características mecánicas y ópticas dinámicas del cristalino durante la simulación de la acomodación ex vivo. El aparato se puede utilizar para el cristalino de ojos de donantes y para el cristalino después de la operación de catarata donde se rellena la cápsula del cristalino con un polímero.

El globo donante se secciona dejando el cristalino y el cuerpo ciliar para poner encima de un dispositivo. El dispositivo permite el estiramiento circunferencial del cristalino simulando la acomodación. El estiramiento se crea por un motor de pasos conectado a un micrómetro y a una balanza que permite medir el desplazamiento y la fuerza. La sección corneal del ojo se va a conectar mediante ocho suturas de Prolene al conjunto del micrómetro y de la balanza. El conjunto funciona haciendo pequeños desplazamientos de 1 a 100 µm con una resolución de 2 µm. El micrómetro tiene una salida digital que permite la medición del desplazamiento con una resolución de 1 µm. El núcleo de una balanza digital sirve para la medición de la fuerza de los estiramientos ligeros (1 a 500 mN) con una resolución de 0.1 mN. Hemos desarrollado programas informáticos para manejar todas las partes mecánicas y la toma de imágenes a través de un solo programa principal (LabView).

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació 3.2. Proyecto Phaco Ersatz 3.2.2. Revisión de los métodos actuales para evitar la opacificación de la cápsula posterior después de la cirugía de la catarata José Lamarca, Julia Sempere Institut Universitari Barraquer En los próximos años van a desarrollarse y perfeccionarse nuevos avances en la tecnología relacionada con la cirugía de la catarata, al igual que en el campo de la OCP. Desde nuestro punto de vista creemos que la solución a la OCP pasa por la investigación y combinación de: l

l

l l

Biomateriales que por su composición y por su forma sean capaces de sustituir al cristalino produciendo mínima reacción.

Prevención de la OCP química que inhiba la proliferación, adhesión y migración de las células de forma inocua.

Prevención de la opacificación de la cápsula anterior Sistemas de análisis de imagen y densitometría aplicados al estudio de la OCP. La cuantificación objetiva del grado de opacificación resulta determinante en estudios de investigación clínica para establecer cuales son los métodos, técnicas, biomateriales o fármacos que poseen una mayor efectividad frente a la OCP.

La bibliografía es muy diversa y hay pocos productos químicos que tengan más de un artículo publicado, por lo que se debe ser cauto a la hora de valorar dichos productos y sus resultados El horizonte de la cirugía de la catarata, se encuentra en encontrar un sistema que ofrezca máximo un parecido máximo al cristalino sano, tanto en refracción como en acomodación.

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació 3.2. Proyecto Phaco Ersatz 3.2.3. Pruebas actuales para la medición objetiva de la acomodación: Estudio bibliográfico Ana Mª Pascual Agúndez Institut Universitari Barraquer Para el estudio objetivo de la acomodación existen fundamentalmente dos tipos de medidas: l

1. Medida con el optómetro: entre los métodos objetivos a utilizar podemos citar la posibilidad de realizar la medición de la amplitud de acomodación por medio de un optómetro. La medida de esta magnitud con los optómetros presenta el inconveniente de que la elevada luminosidad emitida por el test del aparato provoca una miosis con tendencia a producir un espasmo acomodativo que falseará los resultados.

l

2. Método retinoscópico: consiste en determinar la diferencia de valores esquiascópicos que se obtienen al ordenar al sujeto que fije un objeto lejano y un punto próximo, como puede ser el propio retinoscopio.

Este procedimiento retinoscópico para medir la amplitud de acomodación residual tras la aplicación de un ciclopléjico es el método mejor a utilizar en el niño, pues no precisa otro aparato que un buen retinoscopio, aparato que utilizamos en la determinación de su refracción, por lo que con ello no sometemos al pequeño a un examen con nuevos aparatos, ni distraemos su atención en la observación de éstos, ni le hacemos sentir temor alguno, lo que ocurre siempre que se le ordena colocar la cabeza en la mentonera de cualquier aparato. Sin duda alguna, el examen retinoscópico es el menos molesto entre todas las exploraciones a que se somete a un paciente ocular.

En realidad, con este método realizamos lo que venimos llamando esquiascopia dinámica.

Existen en el mercado unos retinoscopios especiales para efectuar este examen, los cuales constan de unos tests con figuras o letras iluminadas y situadas en el cabezal del aparato, que sirven de punto de fijación próximo. Con el fin de no modificar la importante sinergia acomodación-convergencia, es interesante que el sujeto dirija sus ojos ligeramente hacia abajo, siguiendo la dirección normal de los ojos en visión próxima, mientras realizamos la medición siguiendo el eje visual del ojo.

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació 3.2. Proyecto Phaco Ersatz 3.2.4. Medición del espesor de la cápsula del cristalino Ralph Michael1, Francisco Tresserra2, Rodrigo Abreu1, José Lamarca1, Rafael I. Barraquer1 1 Institut Universitari Barraquer, 2 Institut Universitari Dexeus Introducción: En las principales teorías de la acomodación, la elasticidad y el espesor de la cápsula del cristalino se consideran factores importantes para el cambio de forma del cristalino. Por ejemplo, en el estado de acomodación para visión próxima, la parte central anterior del cristalino tiene más curvatura que las partes periféricas.

Propósito: Comprobar el grosor de la cápsula cristaliniana humana (Finchan 1937) y el cambio en el grosor con la edad (Fisher 1988).

Método: Se estudiaron 26 cristalinos humanos procedentes de donantes del banco de ojos con un rango de edad de 12-103 años. Se fijaron en una solución de formaldehído y parafina al 3.6%. Los cortes sagitales se fijaron con tinción PAS. Se tomaron imágenes con un fotomicroscopio. La cápsula cristaliniana se midió cada 250 micras a lo largo del borde sagital del cristalino en impresiones de papel magnificadas 1000 veces.

Resultados: El grosor de la cápsula cristaliniana anterior fue similar a la descrita por Fincham 1937, pero el cambio con la edad fue menos pronunciado que el descrito por Fisher 1988. Sin embargo el grosor de la cápsula posterior fue menor al descrito por Fincham, siendo comparable a Fisher.

Conclusiones: La cápsula cristaliniana humana va sufriendo un engrosamiento que va aumentando con la edad. No hay cambios con la edad en el grosor del polo posterior, periferia posterior y del ecuador para los grupos de edad estudiados.

Publicaciones: Michael R1, Abreu R1, Tresserra F2, Barraquer RI1.

Changes of the human lens capsule thickness between 30 and 100 years of age.

Congress of the European Association for Vision and Eye Research (EVER) 2004, Vilamoura, Portugal 1 Institut Universitari Barraquer, Barcelona, Spain 2 Institut Universitari Dexeus, Barcelona, Spain Abreu González R1, Michael R1, Tresserra F2, Barraquer Compte RI1.

Grosor de la cápsula cristaliniana humana en función de la edad y la localización a lo largo del borde sagital del cristalino.

80 Congresso de la Sociedad Española de Oftalmologia 2004, Cordoba, Spain 1 Institut Universitari Barraquer, Barcelona, Spain 2 Institut Universitari Dexeus, Barcelona, Spain

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

3. Líneas de investigación en desarrollo 3.3. Seguridad de la iluminación de los microscopios quirúrgicos Ralph Michael1, Alfred Wegener2 1 Institut Universitari Barraquer, 2 Experimental Ophthalmology, RFW University, Bonn, Alemania Propósito: Se ha trabajado con la continuación de un proyecto sobre la seguridad de los microscopios quirúrgicos que se aplican en la oftalmología. Se sospecha que la iluminación de estos microscopios puede producir daño en la retina y en el cristalino. Los rayos ultravioletas (UVR) pueden producir la catarata y la luz azul puede dañar el epitelio pigmentario de la retina.

Métodos: En la empresa Zeiss de Alemania se ha medido la intensidad de la luz entre los ultravioletas y infrarrojos desde el microscopio OPMI visu 200. Estas mediciones se han hecho en la superficie donde está el ojo y con la iluminación máxima del microscopio. Los parámetros de la luz fueron calculados usando datos espectrales relativos de la organización "American Conference of Governmental Industrial Hygienists". Con esto hemos calculado el tiempo de la exposición de seguridad del microscopio con respecto a la radiación ultravioleta y la luz azul para el ojo. Se prepararon los cálculos para la fuente de luz sin ningún filtro, con el filtro interno de UVR, el filtro amarillo opcional y una combinación de filtros.

Resultado: El tiempo de la exposición de seguridad para evitar la lesión de UVR en el cristalino y en la córnea resultó ser 2 h sin el filtro, 4 h con el filtro de UVR, 200 h con el filtro amarillo y 400 h con la combinación del filtro. El tiempo de la exposición de seguridad para evitar la lesión fotoquímica retiniana resultó ser 3 minutos sin el filtro y con el filtro de UVR, 10 minutos con el filtro amarillo y 49 minutos con la combinación de filtros. El límite de la exposición para evitar la lesión termal retiniana no fue excedido.

Conclusión: El peligro originado por el componente de UVR del microscopio quirúrgico no es crítico y el tiempo de la operación se puede prolongar con seguridad con el uso de filtros apropiados. El peligro fotoquímico retiniano aparece crítico sin los filtros apropiados, permitiendo sólamente algunos minutos de tiempo de la exposición de seguridad. Los tiempos de la exposición de seguridad calculados están para los casos que tengan las peores condiciones, la iluminación máxima del microscopio, e incluyen un factor 10 de seguridad.

Publicación: Michael R1, Wegener A2.

Estimation of safe exposure time from an ophthalmic operating microscope with regard to ultraviolet radiation and blue-light hazards to the eye.

J Opt Soc Am A Opt Image Sci Vis. 2004 Aug;21(8):1388-92.

1 Institut Universitari Barraquer, Barcelona, Spain 2 Department of Ophthalmology, Rheinische Friedrich-Wilhelms-University, Bonn, Germany

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Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

4. ACTIVIDADES DOCENTES

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

4. Actividades docentes 4.1. Transparency Club Meetings - Anterior Segment Research Group Cada mes se ha organizado una reunión llamada "Transparency Club" o "Club de Transparencia".

El nombre es debido a una de las características más importantes de la córnea y del cristalino.

Participan los oftalmólogos especializados en segmento anterior, los residentes y alumnos máster interesados en el segmento anterior y el equipo del departamento de cirugía refractiva. Se tratan temas clínicos y experimentales en forma de discusión, "brain storming" y ponencias.

Meetings 2004: Tuesday, 30. November 2004, 20:00 at Research Department, COB José & Julia: Posterior Capsular Opacification - Prevention in Phaco Ersatz Tuesday, 16. November 2004, 20:00 at Research Department, COB Preparation of research proposals for Masters and Residents Tuesday, 2. November 2004, 20:00 at Research Department, COB First results form the EU Glare project and discussion about how to compare the data Tuesday, 5. October 2004, 20:00 at Research Department, COB Experiences and News from the congresses EVER, Portugal and SEO, Cordoba.

Tuesday, 29. June 2004, 20:00 at Research Department, COB Changes of the human lens capsule thickness between 30 and 100 years of age.

(Topic, important for accommodation and Phaco-Ersatz) Tuesday, 25. May 2004, 20:00 at Research Department, COB - Information about progress with Phaco Ersatz - Information about EU Glare project - First experiences with TRACEY Tuesday, 20. April 2004, 20:00 at Research Department, COB Selecetion of an apparatus to study the anterior eye segment: Oculus Pentacam - OQAS - TRACEY - NAVEX Tuesday, 24. February 2004, 20:00 at Research Department, COB IOL power calculation in patients with prior corneal refractive surgery Home: www.catedrabarraquer.org Página actualizada: 25 febrero 2005

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

4. Actividades docentes 4.2. Actividades en el European Association for Vision and Eye Research Dr. Ralph Michael trabaja en la junta de la organización European Association for Vision and Eye Research como Board Member y Chair of the Lens and Cataract section.

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www.EVER.be

Special Interest Symposium: Accommodative IOL part 1 Moderators for this session Rafael I. BARRAQUER, Ralph MICHAEL Time and place of session This session will take place on Monday 27 September 2004 from 14:00 till 15:30 in room Fenix III. Abstracts assigned to this session (5) 14:00

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3361

Restoring accommodation in pseudophakic eyes

TASSIGNON MJ

14:18

18'

3362

Hydrogels as potential lens replacement material

RAVI N

14:36

18'

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Model of IOL with changeable optical power

SERGIENKO N

14:54

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3364

Optical and Mechanical Design for Human Implantation of the Sarfarazi Elliptical Accommodating Intraocular Lens (EAIOL)

SARFARAZI FM

15:12

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What is there to be learned about accommodation and presbyopia from in vitro mechanical stretching studies?

GLASSER A

Accommodative IOL part 1 ■ 3361 Restoring accommodation in pseudophakic eyes

■ 3362 Hydrogels as potential lens replacement material

TASSIGNON MJ Ophthalmology, Antwerp

RAVI N Departments of Ophthalmology & Chemical Engineering, St. Louis, Missouri

Purpose Under “restoring” one could ironously understand that accommodation is fully understood. This is currently not the case. Furthermore, the capsular bag and more precisely its healing process after cataract surgery, is still not fully understood making it difficult for the surgeon to predict the final position of the intraocular lens (IOL) in the anterior chamber of the operated eye.

Purpose To develop an injectable accommodating intra-ocular lens for the preservation of accommodation after cataract surgery

Methods An overview of all parameters influencing accommodation will help to better understand the importance of the complexity of the accommodation function.

Specifically for the pseudophakic eye, the healing process of the capsular bag plays a crucial role in the final position of the IOL within the eye. Within that healing process, the LECs play the most important role and are the cells that should be controlled.

Results Intraocular lenses (IOLs) that have their accommodation effect based on the so-called anterior movement of the vitreous gel will loose all benefit in case the position of the intraocular lens is not well aligned according to the visual axis.

Conclusion The final place of the intraocular lens in the eye is crucial. For this purpose we developed a new way of fixation called the bag-in-the-lens implantation. This lens has the advantage that it will not rotate and not defocus. It is therefore possible to develop a customized IOL depending on the corneal aberrations: “corneal optical coupling IOL”.

■ 3363 Model of IOL with changeable optical power SERGIENKO N Purpose A biometry measuring enables objective assessment of IOL forward movement as a result of the pilocarpine-induced contraction. This fact serves an indirect evidence of the vitreous pressure over the posterior lens capsule during accommodative function.Purpose. To develop an IOL model stimulating by vitreous pressure for increasing an optical power of the implant.

Methods A model of the accommodative IOL (A-IOL) is designed with following characteristics: length-10.5 mm, width- 6.5 mm, optical part diameter- 4.75 mm.A developed model of eyeball imitates a capsular bag after performing the circular capsulorhexis. The model is hermitic and allows to control pressure on capsular bag from behind. After placing the A-IOL model in-the-bag of the eyeball it is possibility to observe increasing of the optical power of the implant.

Results Design of the A-IOL allows securing quality of the optical system and degree of the altering of optical power. Demonstration of work of the A-IOL model is presented on video.

Conclusion A possibility of increasing of optical power of IOL following vitreous pressure over the posterior lens capsule is proved. The next step may be developing the IOL model for clinical trial.

Methods As proof of concept, acrylamide derivaties were copolymerized with disulphide containg crosslinkers. The hydrogel was extensively washed with water to remove unreacted monomers and other excipients. The swollen copolymer was liquified to yeild copolyacrylamide containing thiol functional groups. Various concentrations of these copolymers were introduced into pre-evacuated porcine lens capsular bags. The hydrogel formed spontaneously in the presence of oxygen at physiological pH. The mechanical properties were determined using a dynamic mechanical analyzer, and a custom-designed multi arm radial stretcher. Biocompatibility tests were performed on porcine lens epithelial cells in tissue culture medium.

Results The aqueous copolyacrylamide solujtion gelled spontaneously under physiological conditions to form a clear and stable hydrogel. The modulus of the gels ranged from 0.47 -1.1 KPascals, the refractive index varied from 1.35-1.42, and the relaxation time constant from 50-100 milliseconds. The copolymers showed minimum contact toxicity in the thiol form but no toxicity was observed in the disulfide form.

Conclusion We have successfuly developed a hydrophillic phaco-ersatz material that appears to have the right range of optical, mechanical and biocompatible properties.

Animal studies are being planned.

■ 3364 Optical and Mechanical Design for Human Implantation of the Sarfarazi Elliptical Accommodating Intraocular Lens (EAIOL) SARFARAZI FM Harvard Medical School, Carlsbad, CA Purpose The purpose was to improve the design of the three dimensional accommodating IOL designs used for implantation in a human eye.

Methods The Sarfarazi EAIOL is an accommodating IOL composed of two optics and three haptics. The anterior optic is a biconvex plus lens, and the posterior optic is a concave convex minus lens. It is designed to achieve a true accommodation through the natural contraction and relaxation of the capsule by the ciliary muscle. This one-piece foldable lens was molded from a silicone material and implanted in a monkey eye. The mold has been re-designed, optically and mechanically re-calculated and adjusted for the human eye.

Results This newly design EAIOL will be implanted in the human eye through a small incision and the result will be reported. As previously demonstrated, the Sarfarazi EAIOL was implanted in the three monkey eyes. The lens was easily inserted in the eye with a lens folder using relatively small incision surgery. The UBM images confirmed that the Sarfarazi EAIOL fit the entire capsule. Long-term follow-up shows that the EAIOL is very stable and is providing accommodation. No decentration or misalignment has been observed. Implantation in the live monkeys indicated that the lens achieved 7-8 diapers of accommodation in repeated tests utilizing various testing techniques. Surgical technique and slit lamp examinations after implantation were very similar to those of traditional IOLs. Conclusion Initial tests indicate that the Sarfarazi twin-optic Elliptical Accommodating IOL can emulate the performance of the natural lens and can achieve a significant degree of accommodation. Implantation in the monkeys has demonstrated that the lens is safe enough to be implanted in the human eye.

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Accommodative IOL part 1 ■ 3365 What is there to be learned about accommodation and presbyopia from in vitro mechanical stretching studies?

GLASSER A College of Optometry, University of Houston, Houston, TX Purpose Due to the relative inaccessibility of the accommodative structures of the eye there are still many unanswered questions about accommodation and presbyopia. In vitro studies using mechanical stretching of the lens with radially directed forces have provided important insights. The history of these studies since their inception from Fisher’s (1977) pioneering study to testing of new accommodative intraocular lenses and the insights and limitations of this approach, will be detailed.

Methods Fisher (1977), Pierscionek (1993; 1995), Glasser & Campbell (1998) and Glasser (1999); Roorda & Glasser (2004) have used mechanical stretching devices to study the accommodative changes in the natural crystalline lens. These studies and the results obtained have provided the groundwork for new studies in this area such as those

by Koopmans, et al (2003), testing of new accommodative IOLs, and towards the development of a new generation of these devices such as those by Parel, Ravi and Barraquer and colleagues.

Results Mechanical stretching studies support the capsular basis of accommodation, have allowed estimations of the force of contraction of the ciliary muscle, have led to observations that aged human lenses fail to undergo accommodative changes, provided descriptions of the accommodative optical changes that the lens undergoes and provided insight into the lenticular basis of presbyopia. These devices also allow a cost effective method for testing the performance of new accommodative intraocular lenses.

Conclusion While mechanical stretching does not duplicate the accommodative mechanism of the living eye, and suffers from inherent limitations, the results from this line of experimental work has validated mechanical stretching as a reliable and useful approach to investigate some aspects of accommodation, presbyopia and accommodative IOLs.

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Special Interest Symposium: Accommodative IOL part 2 Moderators for this session Ralph MICHAEL, Rafael I. BARRAQUER Time and place of session This session will take place on Monday 27 September 2004 from 17:30 till 19:00 in room Fenix III. Abstracts assigned to this session (4) 17:30

18'

3461

Manual lens stretching apparatuses for optical properties analysis of natural lens, iols and refilled lens capsule (phaco-ersatz)

ACOSTA AC, LAMAR PD, LEE W, DENHAM DB, ABRI A, NOSE I, ZIEBARTH N, BORJA D, OROZCO M, MANNS F, HO A, PAREL JM

17:48

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3462

In vivo experiments of polymer refilling of the capsular bag for presbyopia

KOOPMANS SA, TERWEE T, KOOIJMAN AC, GLASSER A, WENDT M

18:06

18'

3463

Phaco-Ersatz 2004 update: Ex-vivo pre-post lens capsule refilling optomechanical accommodative evaluation.

PAREL JM, LAMAR PD, ACOSTA AC, BILLOTTE C, FERNANDEZ V, ABRI A, DENHAM DB, LEE W, ZIEBARTH N, BORJA D, OROZCO M, MANNS F, HO A, WATLING T, HUGHES T, MANOR B, SWEENEY D, AUGUSTEYN R, HOLDEN B

18:24

18'

3464

Computer controlled lens stretching device

BARRAQUER R, MICHAEL R, CARRETIE R

Accommodative IOL part 2 ■ 3461 Manual lens stretching apparatuses for optical properties analysis of natural lens, iols and refilled lens capsule (phaco-ersatz)

■ 3462 In vivo experiments of polymer refilling of the capsular bag for presbyopia

ACOSTA AC (1, 2), LAMAR PD (1, 3), LEE W (1), DENHAM DB (1), ABRI A (1, 4), NOSE I (1), ZIEBARTH N (1), BORJA D (1, 5), OROZCO M (1, 5), MANNS F (1, 5), HO A (6), PAREL JM (1, 5, 4) (1) Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami, Miami, FL (2) Hospital Oftalmológico Dr P. Lagleyze, Buenos Aires, Argentina (3) Rudolf Foundation Hospital Department of Ophthalmology and Ludwig Boltzmann Institute for Retinology and Biomicroscopic Laser Surgery, Vienna, Austria (4) Rudolf Foundation Hospital Department of Ophthalmology and Ludwig Boltzmann Institute for Retinology and Biomicroscopic Laser Surgery, Vienna (5) Department of Biomedical Engineering, University of Miami, College of Engineering, Miami, FL (6) Vision CRC, University of New South Wales, Sydney

KOOPMANS SA (1), TERWEE T (2), KOOIJMAN AC (1), GLASSER A (3), WENDT M (3) (1) Department of Ophthalmology, Groningen (2) Pfizer, Groningen (3) College of Optometry, Houston, TX

Purpose To design a compact portable instrument to measure and compare the accommodative optical properties of crystalline, implanted IOLs and refilled lens (PhacoErsatz).

Conclusion Objective measurements of refractive- and lens thickness changes are required to demonstrate accommodation in rhesus macaques.

Purpose Demonstration of accommodation in refilled primate eyes.

Methods Polymer refilling of the capsular bag is carried out after removal of the lens nucleus and cortex in iridectomised eyes of rhesus macaques. Accommodation is stimulated with pilocarpine or carbachol iontophoresis and the result is measured with a Hartinger coincidence refractometer and A-scan ultrasound.

Results Accommodative changes are recordable as changes in refraction and changes in lens thickness.

Methods MLSA are hand-held devices to stretch the sclera-ciliary body-zonular apparatus–lens section. MLSA I has 8 independent spring activated segments whereas MLSA II is equipped with a cam system that activates all 8 segments simultaneously by rotating a lever. The devices straddle the globe at the level of the lens. Different segments were built to accommodate different globe diameters. After conjunctival, muscle and fat tissues removal, the globe is glued to the 8 segments using cyanoacrylate adhesive. The posterior pole is sectioned, manual vitrectomy performed and the tissue section flipped over for cornea removal. Dissection of the sclera between the 8 segments is made using thin scissors and the iris is removed. Optical power (+/-0.5D) and zonules/lens diameter (+/-25um) measurements can be obtained using a Scheiner system and a 45o slit-lamp mounted on an operating microscope equipped with CCD and digital camera. The MLSA are also used with the BPEI-Miyake-Apple morphology system and a non-contact optical lens capsule thickness measuring system. Once measurements have been completed, the lens is removed for shadowphotogrammetric assessment and/or the tissue is fixed for histopatology.

Results MLSA was used in human and monkey eyes. An analysis on the effect of tissue preservation and showed a ~5% lens diameter change due to stretch over 3 days when tissues where immersed in BSS at 3oC, whereas no measurable changes occurred after 24 hrs with 0.3% formalin. In an ongoing study, MLSA showed >8% changes occurring in a refilled lens capsule (Phaco Ersatz) but no changes in 4 eyes implanted with conventional IOLs. Conclusion MLSA is a useful tool for accommodation studies.CR: NONE. Support: NIH EY14225; Florida Lions Eye Bank; Vision CRC, Sydney Australia; Fight for Sight; Research to Prevent Blindness, NY, NY; Henri and Flore Lesieur Foundation, Palm Beach, FL.

■ 3463 Phaco-Ersatz 2004 update: Ex-vivo pre-post lens capsule refilling optomechanical accommodative evaluation.

PAREL JM (1, 2, 3), LAMAR PD (4, 1), ACOSTA AC (1, 5), BILLOTTE C (6, 1), FERNANDEZ V (1), ABRI A (4, 1), DENHAM DB (1), LEE W (1), ZIEBARTH N (1, 2), BORJA D (1, 2), OROZCO M (1, 2), MANNS F (1, 2), HO A (7), WATLING T (8), HUGHES T (8), MANOR B (7), SWEENEY D (7), AUGUSTEYN R (7), HOLDEN B (7) (1) OBC/Bascom Palmer Eye Institute University of Miami School of Medicine, Miami (2) Dept of Biomedical Engineering, Univ of Miami College of Engineering, Coral Gables (3) University of Liege Department of Ophthalmology CHU Sart-Tillman, Liege (4) Dept of Ophthalmology, Rudolf Foundation Hospital and Ludwig Boltzmann Institute for Retinology and Biomicroscopic Laser Surgery, Vienna (5) Hospital Oftalmológico Dr P. Lagleyze, Buenos Aires (6) Centre Hospitalier Universitaire de Caen, Caen (7) Vision Cooperative Research Centre, University of New South Wales, Sydney (8) CSIRO, Melbourne Purpose Evaluate the potential of Phaco-Ersatz at restoring accommodation.

Methods Phaco-Ersatz is a lens capsule refilling technique designed to restore accommodation after presbyopia and cataract surgery via a 2mm self-sealing clear corneal incision. Procedure safety, anti-LEC proliferative treatment and polymer biocompatibility were tested in rabbits while effectiveness was assessed using lens stretching apparatus EVAS to measure radial stretching forces, changes in lens diameter, thickness, and optical power. Simulated accommodation in human, rhesus, cynomolgus, baboon and pig cadaver eyes were studied.

Results The effect of radially stretching the circular ciliary muscle by 2 mm only affected the results by less than 10%, accommodation forces ranged from 3 to 13 g and accommodation amplitude from 0 to 1.5D in 40 to 90 year old presbyopic human eyes (avg 0.3D, n=10), to 2.8D in a 5month old pig, to over 20D in young primates eyes (avg 14D, n=44). Up to 13D of accommodation was restored by Phaco-Ersatz in primates (avg 10D, n=10).

Conclusion Lens refilling can restore accommodation

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EVER 2004 - Abstract book

Accommodative IOL part 2 ■ 3464 Computer controlled lens stretching device BARRAQUER R, MICHAEL R, CARRETIE R “Joaquín Barraquer” Chair of Eye Research, Barraquer University Institute, Autonomous University of Barcelona, Barcelona Purpose To design an instrument to measure the mechanical and dynamic optical properties of human donor lenses and refilled lenses during simulated accommodation ex-vivo.

Methods Based on previous designs by Fisher, Glasser, Campbell and Parel the Computer Controlled Lens Stretching Device (CCLSD) consists of a rigid bench for holding and stretching coronal eye sections including the ciliary-lens zone, while allowing front and back axial, as well as oblique observation and measuring. Circumferential stretching is created by a stepper motor coupled to a digital outside micrometer for linear displacement and distance measurement, and a digital balance for load measuring.

This is attached to the specimen through 8 Prolene sutures and plastic plates glued to the sectioned sclera. One web cam is placed above the crystalline lens to monitor the coronary diameter changes and another web cam will be rebuilt to take low resolution Scheimpflug images to monitor sagittal diameter changes during stretching.

Results The CCLSD is a compact, portable lens stretching device with direct measurement of displacement with a precision of 1.25 µm (one step movement of the stepper motor), and of load with precision of 0.1 mN (0.01g). All operating and measuring parts have data output and are computer controlled through LabView routines with a single program, also integrating image acquisition. The apparatus can be used in horizontal or vertical position, for measurements with either laboratory or clinical-design (topography, aberrometry, ray tracing) instruments.

Conclusion The CCLSD offers precision, integrated control and measurement, and portability for lens accommodation studies.

EVER 2004 - Abstract book

219

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

5. PUBLICACIONES

Càtedra de Recerca en Oftalmologia "Joaquim Barraquer" Departament d'Investigació

5. Publications 2004 Michael R1, Wegener A2.

Estimation of safe exposure time from an ophthalmic operating microscope with regard to ultraviolet radiation and blue-light hazards to the eye.

J Opt Soc Am A Opt Image Sci Vis. 2004 Aug;21(8):1388-92.

1 Institut Universitari Barraquer, Barcelona, Spain 2 Department of Ophthalmology, Rheinische Friedrich-Wilhelms-University, Bonn, Germany

Congress presentations 2004 Barraquer RI, Michael R, Carretie R. Computer controlled lens stretching device.

Congress of the European Association for Vision and Eye Research (EVER) 2004, Vilamoura, Portugal Institut Universitari Barraquer, Barcelona, Spain Michael R1, Abreu R1, Tresserra F2, Barraquer RI1.

Changes of the human lens capsule thickness between 30 and 100 years of age.

Congress of the European Association for Vision and Eye Research (EVER) 2004, Vilamoura, Portugal 1 Institut Universitari Barraquer, Barcelona, Spain 2 Institut Universitari Dexeus, Barcelona, Spain Abreu González R1, Michael R1, Tresserra F2, Barraquer Compte RI1.

Grosor de la cápsula cristaliniana humana en función de la edad y la localización a lo largo del borde sagital del cristalino.

80 Congresso de la Sociedad Española de Oftalmologia 2004, Cordoba, Spain 1 Institut Universitari Barraquer, Barcelona, Spain 2 Institut Universitari Dexeus, Barcelona, Spain Home: www.catedrabarraquer.org Página actualizada: 25 febrero 2005

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J. Opt. Soc. Am. A / Vol. 21, No. 8 / August 2004

R. Michael and A. Wegener

Estimation of safe exposure time from an ophthalmic operating microscope with regard to ultraviolet radiation and blue-light hazards to the eye Ralph Michael Institut Universitari Barraquer, Laforja 88, 08021 Barcelona, Spain

Alfred Wegener Department of Ophthalmology, Rheinische Friedrich-Wilhelms-University, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany Received November 6, 2003; revised manuscript received March 2, 2004; accepted March 23, 2004 Hazards from the optical radiation of an operating microscope that cause damage at the corneal, lenticular, and retinal levels were investigated; we considered, in particular, ultraviolet radiation (UVR) and blue light.

The spectral irradiance from a Zeiss operation microscope OPMI VISU 200 was measured in the corneal plane between 300 and 1100 nm. Effective irradiance and radiance were calculated with relative spectral effectiveness data from the American Conference for Governmental and Industrial Hygienists. Safe exposure time to avoid UVR injury to the lens and cornea was found to be 2 h without a filter, 4 h with a UVR filter, 200 h with a yellow filter, and 400 h with a filter combination. Safe exposure time to avoid retinal photochemical injury was found to be 3 min without a filter and with a UVR filter, 10 min with a yellow filter, and 49 min with a filter combination. The effective radiance limit for retinal thermal injury was not exceeded. The hazard due to the UVR component from the operating microscope is not critical, and operation time can be safely prolonged with the use of appropriate filters. The retinal photochemical hazard appears critical without appropriate filters, permitting only some minutes of safe exposure time. The calculated safe exposure times are for worstcase conditions and maximal light output and include a safety factor. © 2004 Optical Society of America OCIS codes: 170.4470, 170.3890.

1. INTRODUCTION Ultraviolet radiation (UVR) with wavelengths below 295 nm is completely absorbed by the cornea. Therefore it can cause injury only to the cornea (photokeratitis) and to the directly exposed conjunctiva. Longer wavelengths of UVR reach the crystalline lens and are known to have the potential to induce cataracts.1,2 UVR with wavelengths above approximately 350 nm passes the lens and may reach the retina. This UVR wave band and blue light are postulated to cause age-related macular degeneration.3,4 With age, the lens absorbs more and more UVR and blue light and, in this way, protects the retina. After removal of the crystalline lens during a cataract operation, aphakic patients and patients with artificial intraocular lenses exposed to UVR and blue light are again at higher risk for retinal hazards due to optical radiation.

There are a number of publications describing clinical cases of retinal damage attributed to the use of ophthalmic instruments including operating microscopes.

One report describes two cases of light-induced damage of the retina after slit-lamp photography, both of them in pseudophakic patients.5 Central macular defects, similar to a photocoagulation, are described. More frequently, light-induced maculopathy or retinopathy is reported after cataract extraction6–8 or prolonged retinal exposure during other ocular surgery.9 Khwarg et al.7 1084-7529/2004/081388-05$15.00

states an incidence of 7% for operating-microscope lightinduced retinopathy in a study of 135 consecutive cataract operations. Fortunately, such lesions after cataract surgery have usually no effect on central visual acuity, and the lesions are above or below the macula.6,7 To our knowledge, there are no publications attributing UVR from the light sources in ophthalmic instruments to ocular injury. However, manufacturers of surgical microscopes, ophthalmic surgeons, and the public are concerned about the effects of UVR in ocular surgery. This might be triggered by the public attention to the general health risk due to UVR. There are a few reported cases in which people received significant UVR doses from artificial sources and subsequently developed cataracts that could be correlated to that exposure.10,11 Today, ophthalmic operating microscopes have several features to reduce the potential hazards of the microscope illumination to the patient and the surgeon. Halogen lamps with built-in UVR filters are used in modern operating microscopes. The microscopes may also include optional yellow filters that reduce the exposure to blue light.

Specific filter combinations are discussed in the literature, which reduce the amount of blue light even more.12 Today’s fiber-optic illumination systems have a more homogeneous illumination spot at the retina as compared with older systems using incandescent lamps that pro© 2004 Optical Society of America

R. Michael and A. Wegener

Vol. 21, No. 8 / August 2004 / J. Opt. Soc. Am. A

duce inhomogeneous illumination at the retina with local bright spots. The Zeiss operation microscope OPMI VISU 200 (Carl Zeiss, Germany) has the option of a retinal protection device that delivers less illumination in the central illumination area (patented in Germany as DE 33 39 172 C2, published May 15, 1985). The same instrument also has a field stop to reduce intraocular glare and hence gives more contrast for the surgeon’s view (patented in Germany as G 91 03 433.7, published August 1, 1991).

Previous studies evaluating the risk of light damage during the use of ophthalmic instruments include a publication by Calkins et al.13 They made thorough geometrical calculations of the light reaching the retina in patients treated with several ophthalmic instruments but did not apply spectral-resolved radiation data. Sliney and Armstrong14 are probably the first who analyzed the hazards from several operating microscopes by using spectral-resolved radiation data weighted against sensitivity functions. Stiller and Rassow15 and the Health Council of the Netherlands16 evaluated the risk of thermal and blue-light damage by using spectral functions but did not specifically include UVR hazards from operating microscopes. Van den Biesen et al.17 calculated threshold exposure times for endoillumination during vitrectomy by using spectral data from the International Commission on Non-Ionizing Radiation Protection.

In the present study, spectral irradiance was measured from a Zeiss OPMI VISU 200 operating microscope to estimate the hazards of causing damage at the corneal, lenticular, and retinal levels. We considered different types of optical radiation, in particular UVR and blue light.

The guidelines of the American Conference for Governmental and Industrial Hygienists18 (ACGIH) are applied.

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2. METHODS Spectral irradiance from an operating microscope OPMI VISU 200 was measured in the plane of the patient’s eye

Fig. 1. Illumination light path of the Zeiss operating microscope OPMI VISU 200 with a two-mirror illumination system consisting of a switchable mirror (⫹2° and ⫺2°) and a main mirror at 6° illumination angle (above) and mirror assembly as seen by the patient’s eye (below).

Table 1. Safe Exposure Times and Integrated Radiance and Irradiance Data from the Zeiss Operating Microscope OPMI VISU 200a Measurement Safe exposure time to avoid UVR injury to lens and cornea (ACGIH)18 (h) Safe exposure time to avoid retinal photochemical injury (ACGIH)18 (min) Safe exposure time to avoid aphakic retinal photochemical injury (ACGIH)18 (min) Integrated spectral irradiance weighted against the peak of the spectral effectiveness curve for UVR (ACGIH)18 (180–400 nm) in W/cm2 Integrated spectral radiance weighted against the blue-light hazard function (ACGIH)18 (305–700 nm) in W/(cm2 sr) Integrated spectral radiance weighted against the retinal thermal hazard function (ACGIH)18 (385–1100 nm) in W/(cm2 sr) UVR-A integrated irradiance (315–400 nm) in mW/cm2 Visual integrated irradiance (400–770 nm) in mW/cm2 Infrared integrated irradiance (770–1100 nm) in mW/cm2 Illuminance (400–770 nm) in lux a

Without Filter

UVR Filter

UVR ⫹ Yellow Filter

UVR ⫹ Filter Combination12

1.9

4.0

200

400

3.0

3.1

9.7

49

2.2

2.8

9.6

48

0.45

0.21

0.0042

0.0021

0.550

0.530

0.170

0.034

10.7

10.5

6.9

2.2

0.98

0.19

0.0038

0.0019

82.3

81.6

74.9

22.6

13.7

13.7

13.7

12.7

224,000

224,000

222,000

57,000

For worst-case conditions and maximal light output and including a safety factor.

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and was between 300 and 1100 nm (spectrometer modules MCS 400 and MMS1, Carl Zeiss, Germany). The microscope illumination was operated with maximal light output and the voltage setting to 12.7 V. The light source inside the operating microscope was a fiber-optic system (Retrolux CS, Carl Zeiss, Germany) with a halogen lamp (Philips, The Netherlands). The irradiance was measured with and without a UVR filter.

Spectral irradiance was calculated for a combination of the irradiance from the OPMI with a built-in UVR filter and the optional yellow filter (GG 475, thickness of 1 mm, Schott, Mainz, Germany), which is a long-pass filter with 50% cutoff at 475 nm. The theoretical spectral irradiance output of the OPMI with a UVR filter and a filter combination suggested by Landry et al.12 was also calculated. These additional filters included 2.5-mm-thick Hoya glass filters: G-550, V-30, and Y-46.

Spectral radiance outside the patient’s eye was calculated on the basis of the geometry of the apparent light source and the measured spectral irradiance. The OPMI has a two-mirror illumination system (patented in Germany as DE 40 28 605 C2, published March, 12 1992) (Fig. 1). The apparent solid angle of both mirrors was carefully calculated and checked by experimental projection through a pinhole and found to have a value of 0.0154 sr. Radiance is then calculated as irradiance divided by the solid angle. Effective irradiance and radiance were calculated with relative spectral effectiveness data from the ACGIH18 for UVR injury, retinal photochemical injury, and retinal thermal injury (Table 1).

Safe exposure time to avoid UVR injury is calculated as 0.003 J/cm2 divided by the integrated spectral irradiance weighted against the peak of the spectral effective curve for UVR.18 In addition, unweighted integrated irradiance in the UVR-A (␭ ⫽ 315– 400 nm) should not exceed 1.0 mW/cm2 for exposure periods lasting 1000 s or more.18 Safe exposure time to avoid retinal photochemical injury is calculated as 100 J/(cm2 sr) divided by integrated spectral radiance weighted against the blue-light hazard function for phakic and aphakic conditions.18 Integrated spectral radiance weighted against the retinal thermal hazard function is compared with the limit calculated for a 10-s exposure: 17 W/(cm2 sr).18

3. RESULTS The spectral irradiance of the OPMI at the plane of the patient’s eye is given in Fig. 2. Irradiance without UVR filter and with UVR filter represents measured data. Irradiance with UVR and yellow filter and with UVR and filter combination are calculated with the transmission spectra of the respective filters. UVR below 350 nm is not measurable for all filter options. The UVR filter absorbs radiation below 380 nm, and the yellow filter absorbs radiation below 450 nm. The filter combination reduces the amount of blue light as well as other components of the visible spectrum (Fig. 2).

Applying the ACGIH guidelines to the calculations for the OPMI, safe exposure time to avoid UVR injury to the lens and cornea was found to be 2 h without UVR filter, 4 h with UVR filter, 200 h with UVR and yellow filter, and 400 h with UVR and filter combination. In addition, the

R. Michael and A. Wegener

Fig. 2. Spectral irradiance from the Zeiss operating microscope OPMI VISU 200 for different filter options at the plane of the patient’s eye. (Filter combination from Landry et al.12)

ACGIH limit of 1.0 mW/cm2 unweighted integrated UVR-A irradiance for periods lasting 1000 s or more is not exceeded for all filter options (Table 1). Safe exposure time to avoid retinal photochemical injury was found to be 3 min without UVR filter and with UVR filter, 10 min with UVR and yellow filter and 49 min with UVR and filter combination. These values are for individuals without cataract surgery (phakic conditions). To protect an individual having a crystalline lens removed (aphakes) against retinal photochemical injury, safe exposure time was 2.2 min without a UVR filter. For all other filter combinations, the results were practically equal to the phakic conditions (Table 1). The effective radiance limit for retinal thermal injury was not exceeded for all filter options.

There was no measurable output of UVR-C (␭ ⫽ 180– 280 nm) and UVR-B (␭ ⫽ 280– 315 nm) from the OPMI for all filter options. Measured and calculated irradiance of UVR-A (␭ ⫽ 315– 400 nm) is given in Table 1 along with data for the visible and near-infrared radiation. Illuminance (visible radiation considering the human spectral luminous efficiency) is considerably lower for the UVR and filter combination option (Table 1).

4. DISCUSSION The calculated safe exposure times are for worst-case conditions and maximal light output and include a safety factor. They are based on measured spectral irradiance produced by the OPMI VISU 200 and on the recommendations and spectral weighting functions by the ACGIH.18 The ACGIH recommendations consider the conditions in the working environment and are not explicitly established for the situation of ophthalmic operations.

However, specific standards by the International Organization for Standardization (ISO) for ophthalmic instruments (ISO Committee Draft 17856) and for operation microscopes (ISO Final Draft International Standard 10936) are still in a draft form that is inadequate for application here.

The hazard due to the UVR component of the illumination from the OPMI is not critical, and operation time can be safely prolonged with the use of appropriate filters.

However, ACGIH guidelines on UVR consider damage to the lens and cornea, which absorb this radiation to a large

R. Michael and A. Wegener

extent. In aphakic or pseudophakic conditions, UVR could reach the retina and induce damage there.

The threshold value for retinal thermal injury was not exceeded by the OPMI with all described filter options.

The ACGIH guidelines give this threshold value only for exposures up to 10 s because in the working environment there is a normal adverse eye response. The Health Council of the Netherlands16 had developed guidelines for retinal thermal injury for exposure times exceeding 10 s.

They applied their guidelines to a typical operating microscope and found that the threshold value is not exceeded for all exposure times. Stiller and Rassow15 calculated the retinal thermal injury via the retinal temperature rise, which was found to be less than 5 °C for most operating microscopes.

Retinal photochemical hazard (or blue-light hazard) from the illumination system of the OPMI appears to be critical without appropriate filters, permitting only some minutes of safe exposure time. In aphakic conditions, the crystalline lens no longer serves as a natural UVR filter, and the safe exposure time becomes even shorter for the operating-microscope illumination without UVR filter (Table 1). These calculations are for worst-case conditions and maximal light output and include a safety factor. The ACGIH guidelines do not state the safety factor, which is usually between 5 and 10. The Health Council of the Netherlands16 mentions a safety factor 33 for photochemical damage. Our results are comparable with other similar operating microscopes investigated in the literature. According to their own calculations, Stiller and Rassow15 found the safe exposure time to avoid retinal photochemical injury from different operating microscopes under worst-case conditions between 4 and 7 min.

The Health Council of the Netherlands16 had published a time interval of 17 min to avoid retinal photochemical injury from halogen lamps used in operating microscopes.

Safe exposure time for the OPMI can be prolonged to 49 min with the use of the filter combination suggested in the literature12 according to our calculations. However, the amount of visible light is only 57 000 lx as compared with 220 000 lx with all other filter options (Table 1).

Whether this lower illuminance level together with an altered color balance is practical for the work of the surgeon must be tested.

One may wonder why there are relatively few clinical reports about retinal injury after ophthalmic operations with safe exposure times of only a few minutes as reported in the literature and in this study. First, the estimations are for worst-case situations with maximum lamp voltage, and they include a safety factor. They also assume that the same spot of the retina is exposed continuously, which is probably not the case because of eye movement, instrument movement, and surgeons’ hands interrupting the illumination path. Light-induced retinopathy after cataract surgery has usually no effect on central visual acuity, and the lesions are above or below the macula6 and may be difficult to detect.

A recent study by Lund19 suggests that the eye’s damage threshold to short exposure of blue-laser light is approximately 16 times higher than the previously published data indicated. To our knowledge, this new finding has not yet been published in a peer-reviewed

Vol. 21, No. 8 / August 2004 / J. Opt. Soc. Am. A

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journal and probably needs more investigation before any changes of the current safety standards are made.

It could be concluded that a UVR filter should always be used, furthermore because UVR is not prerequisite for ophthalmic surgery. Yellow filters are also highly recommended to reduce the risk of UVR and blue-light hazards.

They do not alter the visible light output significantly (Table 1); however, the influence on the color balance of illuminating light has to be studied. It might be also interesting to consider such filters in artificial intraocular lenses to protect the retina in pseudophakic eyes. Intraocular lenses with yellow filters are, in fact, currently being tested by some pharmaceutical companies. Filter combinations that filter out even more blue light from the operating-microscope illumination are other interesting options to reduce the risk to damage the retina during ophthalmic operations.

Corresponding author Ralph Michael’s e-mail address is ralph.michael@web.de.

REFERENCES 1.

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6.

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R. Michael, ‘‘Development and repair of cataract induced by ultraviolet radiation,’’ Ph.D. thesis (Karolinska Institutet, Stockholm, 2000). Published in Ophthalmic Res. 32 (Suppl.

1), 1–44 (2000).

D. H. Sliney, ‘‘How light reaches the eye and its components,’’ Int. J. Toxicol. 21, 501–509 (2002).

H. R. Taylor, B. Munoz, S. West, N. M. Bressler, S. B. Bressler, and F. S. Rosenthal, ‘‘Visible light and risk of agerelated macular degeneration,’’ Trans. Am. Ophthalmol.

Soc. 88, 163–178 (1990).

S. Beatty, H. Koh, M. Phil, D. Henson, and M. Boulton, ‘‘The role of oxidative stress in the pathogenesis of age-related macular degeneration,’’ Surv. Ophthalmol. 45, 115–134 (2000).

S. Kohnen, ‘‘Light-induced damage of the retina through slit-lamp photography,’’ Graefes Arch. Clin. Exp. Ophthalmol. 238, 956–959 (2000).

H. R. McDonald and A. R. Irvine, ‘‘Light-induced maculopathy from the operating microscope in extracapsular cataract extraction and intraocular lens implantation,’’ Ophthalmology 90, 945–951 (1983).

S. G. Khwarg, F. A. Linstone, S. A. Daniels, S. J. Isenberg, T. A. Hanscom, M. Geoghegan, and B. R. Straatsma, ‘‘Incidence, risk factors, and morphology in operating microscope light retinopathy,’’ Am. J. Ophthalmol. 103, 255–263 (1987).

G. Kleinmann, P. Hoffman, E. Schechtman, and A. Pollack, ‘‘Microscope-induced retinal phototoxicity in cataract surgery of short duration,’’ Ophthalmology 109, 334–338 (2002).

K. O. Karp, T. P. Flood, A. L. Wilder, and R. J. Epstein, ‘‘Photic maculopathy after pterygium excision,’’ Am. J. Ophthalmol. 128, 248–250 (1999).

S. Lerman, ‘‘Human ultraviolet radiation cataracts,’’ Ophthalmic Res. 12, 303–314 (1980).

U. Mu¨ller-Breitenkamp, O. Hockwin, H. Siekmann, and V. Dragomirescu, ‘‘Ultraviolet radiation as cataract risk factor—a case report,’’ Dev. Ophthalmol. 27, 76–80 (1997).

R. J. Landry, S. A. Miller, and G. A. Byrnes, ‘‘Study of filtered light on potential retinal photic hazards with operation microscopes used for ocular surgery,’’ Appl. Opt. 41, 802–804 (2002).

J. L. Calkins, B. F. Hochheimer, and S. A. D’Anna, ‘‘Potential hazards from specific ophthalmic devices,’’ Vision Res. 20, 1039–1053 (1980).

D. E. Sliney and B. C. Armstrong, ‘‘Radiometric evaluation of surgical microscope lights for hazards analyses,’’ Appl.

Opt. 25, 1882–1889 (1986).

H. Stiller and B. Rassow, ‘‘Light hazards to the patient’s

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16.

17.

J. Opt. Soc. Am. A / Vol. 21, No. 8 / August 2004 retina from ophthalmic instruments,’’ Appl. Opt. 30, 2187– 2196 (1991).

Health Council of the Netherlands, ‘‘Health-based exposure limits for electromagnetic radiation in the wavelength range from 100 nanometer to 1 millimeter,’’ Rep. 1993/09E (Health Council of the Netherlands, Den Haag, The Netherlands, 1993).

P. R. van den Biesen, T. Berenschot, R. M. Verdaasdonk, H. van Weelden, and D. van Norren, ‘‘Endoillumination during

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19.

vitrectomy and phototoxicity thresholds,’’ Br. J. Ophthamol.

84, 1372–1375 (2000).

American Conference of Governmental Industrial Hygienists, Documentation of the Threshold Limit Values for Physical Agents, 7th ed. (American Conference of Governmental Industrial Hygienists, Cincinnati, Ohio, 2001).

D. Lund, ‘‘Retinal injury thresholds for blue wavelength lasers,’’ presented at the International Laser Safety Conference, Jacksonville, Florida, March 10–13, 2003.

EVER

Page 1(1)

i3464 - Computer controlled lens stretching device

Topics Lens - Clinical sciences - Other Additional information Use of Powerpoint Session information This abstract has been assigned to session Accommodative IOL part 2.

This session will take place on Monday 27 September 2004 from 17:30 till 19:00 in room Fenix III.

Abstract Author 1

BARRAQUER R "Joaquín Barraquer" Chair of Eye Research, Barraquer University Institute, Autonomous University of Barcelona (Barcelona)

Author 2

MICHAEL R "Joaquín Barraquer" Chair of Eye Research, Barraquer University Institute, Autonomous University of Barcelona (Barcelona)

Author 3

CARRETIE R "Joaquín Barraquer" Chair of Eye Research, Barraquer University Institute, Autonomous University of Barcelona (Barcelona)

Purpose

To design an instrument to measure the mechanical and dynamic optical properties of human donor lenses and refilled lenses during simulated accommodation ex-vivo.

Methods

Based on previous designs by Fisher, Glasser, Campbell and Parel the Computer Controlled Lens Stretching Device (CCLSD) consists of a rigid bench for holding and stretching coronal eye sections including the ciliary-lens zone, while allowing front and back axial, as well as oblique observation and measuring. Circumferential stretching is created by a stepper motor coupled to a digital outside micrometer for linear displacement and distance measurement, and a digital balance for load measuring. This is attached to the specimen through 8 Prolene sutures and plastic plates glued to the sectioned sclera.

One web cam is placed above the crystalline lens to monitor the coronary diameter changes and another web cam will be rebuilt to take low resolution Scheimpflug images to monitor sagittal diameter changes during stretching.

Results

The CCLSD is a compact, portable lens stretching device with direct measurement of displacement with a precision of 1.25 µm (one step movement of the stepper motor), and of load with precision of 0.1 mN (0.01g). All operating and measuring parts have data output and are computer controlled through LabView routines with a single program, also integrating image acquisition. The apparatus can be used in horizontal or vertical position, for measurements with either laboratory or clinical-design (topography, aberrometry, ray tracing) instruments.

Conclusions

The CCLSD offers precision, integrated control and measurement, and portability for lens accommodation studies.

http://www.ever.be/view_abstract.php?abs_id=991&action=print

03/11/2004

EVER

Page 1(1)

i1431 - Changes of the human lens capsule thickness between 30 and 100 years of age

Topics Lens - Cell / tissue culture - Morphology Additional information Oral presentation / Use of Powerpoint / Rapid fire welcome Session information This abstract has been assigned to session Free Paper Session: Lens Clinical.

This session will take place on Saturday 25 September 2004 from 17:30 till 19:00 in room Pegasus.

Abstract Author 1

MICHAEL R Institut Universitari Barraquer (Barcelona)

Author 2

ABREU R Institut Universitari Barraquer (Barcelona)

Author 3

TRESSERRA F Institut Universitari Dexeus (Barcelona)

Author 4

BARRAQUER R I Institut Universitari Barraquer (Barcelona)

Purpose

To verify the anterior peripheral thickening of the human lens capsule (Fincham 1937) and the change in thickness with age (Fisher 1988).

Methods

Altogether 25 human donor lenses (age between 30 and 100 years) were fixed in 3.6 % buffered formaldehyde and paraffin embedded. Sagittal sections were stained for collagen with periodic acid-Schiff (PAS) stain. Images of the lens border were taken with a Zeiss Photomicroscope, a 25x objective and a digital camera. Capsule thickness was measured every 250 µm along the sagittal lens border and the data was evaluated by regression analysis.

Results

Capsular thickness at the posterior pole (2 µm), posterior periphery (4 µm) and equator (7 µm) is not changing with age. There was an increase in the thickness at the anterior pole from the youngest to the oldest lenses (10 to 15 µm). Anterior peripheral thickening of the lens capsule was seen in all age groups and was increasing with age (13 to 16 µm).

Conclusions

The human lens capsule shows an anterior peripheral thickening at the age of 30 years.

This thickening is increasing with age. There is no change in capsular thickness at posterior pole, posterior periphery and equator for the investigated age groups. Anterior peripheral thickening of the lens capsule was found to be very similar to that described by Fincham 1937, but less pronounced changing with age as described by Fisher 1988.

However, the posterior peripheral thickening was found minor as described by Fincham, comparable to Fisher 1988. Interesting is the steep increase of capsular thickness between the equator and the anterior periphery.

http://www.ever.be/view_abstract.php?abs_id=1067&action=print

03/11/2004

Abreu R.

Grosor Cápsula Cristaliniana

GROSOR DE LA CÁPSULA CRISTALINIANA HUMANA EN FUNCIÓN DE LA EDAD Y LA LOCALIZACIÓN A LO LARGO DEL BORDE SAGITAL DEL CRISTALINO. ABREU GONZÁLEZ RODRIGO. MICHAEL RALPH. TRESSERRA FRANCISCO. BARRAQUER COMPTE RAFAEL. PROPÓSITO: Comprobar el grosor de la cápsula cristaliniana humana (Finchan 1937) y el cambio en el grosor con la edad (Fisher 1988).

MÉTODO: Se estudiaron 26 cristalinos humanos procedentes de donantes del banco de ojos con un rango de edad de 12-103 años. Se fijaron en una solución de formaldehído y parafina al 3.6%. Los cortes sagitales se fijaron con tinción PAS. Se tomaron imágenes con un fotomicroscopio. La cápsula cristaliniana se midió cada 250 micras a lo largo del borde sagital del cristalino en impresiones de papel magnificadas 1000 veces.

RESULTADOS: El grosor de la cápsula cristaliniana anterior fue similar a la descrita por Fincham 1937, pero el cambio con la edad fue menos pronunciado que el descrito por Fisher 1988. Sin embargo el grosor de la cápsula posterior fue menor al descrito por Fincham, siendo comparable a Fisher.

CONCLUSIONES: La cápsula cristaliniana humana va sufriendo un engrosamiento que va aumentando con la edad. No hay cambios con la edad en el grosor del polo posterior, periferia posterior y del ecuador para los grupos de edad estudiados.

13