scleral lens on keratoconus with dry eyes and piguecula case study

Case Study Scleral Lens on Keratoconus associated with Dry Eyes and Piguecula Abstract Patient had a history of bilateral keratoconus, he was submitted to post-intrastromal rings implants and then he underwent to a reverse procedure to extract the intracorneal rings as he had a extrusion of one segment; He also was submitted to Collagen Crosslinking with Riboflavin under UV Rays in both eyes. His vision was never improved with both the previously procedures. He visited several practitioners in Brazil and in the US where he lived for a year studying. He was fit in the US with hybrid lenses and it worked for a some months until he developed intolerance to the lens, presenting hyperemia and burning sensation after 7 to 8 hours of continued wear and decreasing time until he just could not wear them anymore .

Back in Brazil the patient was not able to wear his hybrid contact lenses and was fit with Rose K2 which he could tolerate up to 5 to 6 hours of continued wear or making interruptions so he could rest his eyes and get the lens back to wear so he could work.

He was fit with scleral GP lenses and the results were an optimal fitting relationship, great comfort, increased wearing time and an optmal visual acuity.

Introduction The patient came from Sao Paulo to see us at IOSB in south Brazil, he informed us that he just had given up to find a solution for his problem and was about to submit himself to a corneal transplant until he heard about our work in south Brazil and thought giving a last shot, he told us exactly these words: “You guys are my last hope.”

It is a real challenge when a patient say something like that, we told him that we were up to give our best to resolve his problem and that he could count on us. The real difficulties in this case is the long history of failures and the complications that arose from previous treatments and contact lens fittings. This case was conducted by Dr. Marcelo Bittencourt, MD and me in respect to the clinical consultation and lens customization. Beyond that, we had only five week days to resolve the fit as the patient works in a large multinational and his presence was required after that time.

Case Report Patient R.P.A., male, 32 years old, Engineer, bilateral keratoconus, underwent intrastromal ring implants, another procedure to extract the rings and then submitted to corneal crosslinking (CXL). He developed lens intolerance after six months of hybrid lens wear, he described that during the time he was in the US he was able to wear the lens for 12 to 13 hours a day and suddenly had an episode of redness and the wearing time decreased rapidly until he could not tolerate the hybrid lens wear anymore. He also referred burning sensation during lens wear. Back in Brazil he was fit with Rose K2 in both eyes and wearing time was up to 5 to 6 hours daily until the redness appear. The patient became very sensitive and he presents redness occasionally and spontaneously, we attributed this due to lacrimal deficiency as a probable cause.

Contact Lens Examination and Fit Evaluation - Day one In the first examination the patient presented a tear break-up time (T-But) of 5 to 6 seconds and we also observed a bilateral pinguecula. He was previously instructed to interrupt the GP lens wear for four days prior to examination so we could make sure there was no influence of corneal topography. Despite the crosslinking procedure and also to the fact that at his age the cornea is already more stable keratoconic eyes commonly have an altered corneal hysteresis and a weaker biomechanical resistance.

His Ks readings were:

OD OS

46.62 x 49.12 @ 135° 52.12 x 45.87 @ 57°

Rx readings were:

OD OS

-6.25 = -2.75 @ 118° -8.00 = -4.12 @ 48°

UCVA

OD OS

20/80 20/200

Images below show the initial examination, figures 1a and 1b are front and slitlamp 45째 cross section views of right eye and 2a and 2b are of the left eye. The patient is prone to conjunctival hyperemia and he relates that this occurred about one year after the CXL procedure done a few years back.

Fig. 1a: Right eye front view, note redness.

Fig. 1b: Slitlamp 45째 cross section turned right.

Fig. 2a: Left eye front view.

Fig. 2b: Slitlamp 45째 cross section turned right.

The images above show a less irregular surface at the right eye and a more prolate, ectasic cornea at left eye.

We obtained both corneal topography and anterior segment tomography (Pentacam, Oculus) for both eyes. It is interesting that we obtained similar patterns from both exams but corneal topography only cover about 8 to 9 mm of the central cornea and it seems that is tends to exaggerate the steeper values specially at the center cornea. On the other hand the Pentacam exam covered 12 mm. of the cornea and also supply the white-to-white measure which in turn is a benefic information if you plan to fit scleral lenses. See these exams below in figures 3a and 3b.

Fig. 3a: White-to-white measurement.

Fig. 3b: Scheimpflug and a graded 3D cornea.

In the images below the Anterior Sagital Curvature topography obtained with the Pentacam covering 12 mm of the cornea which represents a major help predicting the initial trial scleral lens to each individual eye, figures 4a and 4b.

Figures 4a and 4b: Anterior Sagittal Curvature along 12.0 mm of both corneas

First Contact Lens Test The first attempt was to fit RGP lenses was with the Ultracone Nipple model manufactured by Ultralentes. This design has an overall diameter from 8.2 up to 9.2 mm. and with a progressive aspheric transition zone (Figures 5a and 5b). The patient asked us to try this type of lens first as he was wearing similar lenses and this was his only pair. We succeed to fit the patient with this GP lens design but again we discussed about the scleral lens due to his tear film instability which would cause again discomfort after continued wear.

The patient agreed to give a try and we moved forward to initial scleral lens tests.

Note the staining with fluorescein due to a tear film instability. We used a flurescein strip but even though, the amount of the contrast mixed with a viscous solution may induce one that the fit is fine, but after a few hour you will not find these patterns and the patient will need to instill artificial tears and it will not be as good as a permanent hidratation during waking hours.

Fig. 5a: OD fit with Ultracone Nipple.

Fig. OS fit with Ultracone Nipple.

Testing the Scleral Bastos Lens We used the analysis of the topographic maps generated by anterior segment tomography of the Pentacam and also corneal assessment of the slit lamp cross-section view we were able to determine the initial trial scleral lens. We observed that the right eye had a less irregular overall surface compared with the left eye and then it was relatively easy to find the correct scleral lens design, base curve, diameter and sagittal value to the trial lens.

Initial trial lenses were the Scleral Bastos model in AO, lens parameters were:

OD BC 43.00 Power -5.00 OS BC 47x43 Power -6.00

OAD 18.5 mm. SAG 5.701 ULTRAFLAT SB Optimum Extra OAD 18.0 mm. SAG 5.791 ULTRACONE SB Optimum Extra

At the right eye the Ultraflat Scleral Bastos design allowed us to obtain a good alignment with a good corneal and limbal clearance resting smoothly on the sclera. This design has a larger optical zone than other scleral lenses and has a wide field of aplications from flatter, surgical corneas to the mild to moderated corneal ectasias. The Ultracone SB model has two base curves, being the optical zone also larger than usual it allows to achieve even greater sagital values than usual with scleral lenses. Both designs have a technology we called Spline Wave Technology which allow tear or liquid lens reservoir exchange.

We believe that tear exchange plays an important roll in providing sufficient oxygen transmission to the cornea, avoiding hypoxia due to the large area covered by the lens and the fact that scleral lenses are thicker than corneal RGPs. Oxygen transmissibility is inversely proportional to lens thickness so we believe that if the lens allow even a slow liquid replacement this is good for the overall physiological health of the eye surface but especially to the cornea. The imprisonment of the liquid reservoir seen in sealed scleral lens fit may cause the exhaustion of the oxygen supply, depending of other factors this may happen even with the super-high oxygen permeable materials, this may vary from case to case, from a specific design to other. Below images from initial trial lens evaluation in figures 6a to 6f.

Fig. 6a: Slit lamp front view, Ultraflat SB (OD)

Fig. 6b: Cross section view, turned right (OD)

Fig. 6c: Slit lamp front view, Ultracone SB (OS)

Figure 6d: Cross section view, turned right (OS)

The corneal clearance was obtained and we could determine minor modifications to improve clearance at the limbus. Both eyes presented an optimal clearance and sagitall depth with slow but effective lacrimal exchange. Images below show the fluorescein after 5 to 7 minutes being instilled over the trial lenses within a lubricated fluorescein strip.

Fig. 6f: Left eye, trial lens evaluation.

Fig. 6e: Right eye, trial lens evaluation.

Final Scleral Lens - Day Two Obtaining the desired corneal and limbus clearance was not a problem, we just planned a larger optical zone with a larger transition to avoid it. The major difficult was yet to come as you can see next. The final scleral lens parameters were:

OD BC 42.75 OS BC 46.50 x 42

Pwr. -3.50 Pwr. -6.50

OAD 18.8 mm.

OAD 18.8 mm.

SAG 5.913 SAG 5.943

Optimum Extreme DK 125 Optimum Extreme DK 125

BCVA with the sclerals: Right eye 20/20 and Left eye 20/25 Note that despite the fact we programmed a flatter base curve, the sagittal value was increased by the changes done at the optical zone an overall diameter in order to achieve a better alignment and guarantee clearance at the limbus. We were able to dispense and educate the patient to insertion, removal, handling and cleaning of his scleral lenses. The lens was very satisfactory for both patient and us at the moment, but we did noticed what seemed to be a mild haptic compression at the pinguecula, nasally so we need time to re-evaluate.

Scleral and conjunctiva evaluation - RIGHT EYE

Fig. 7a: Temporal sclera

Fig. 7b: Upper sclera

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Fig. 7c: Nasal sclera

Nasal pinguecula

Fig. 7d: Underlying sclera

Scleral and conjunctiva evaluation - LEFT EYE

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Fig. 8a: Nasal sclera

Nasal pinguecula

Fig. 8b: Upper sclera

Fig. 8c: Temporal sclera

Fig. 8d: Underlying sclera

Dealing with unexpected difficulties - Day Three As we had only five days to resolve the fitting because the patient had to come back home and to work, we asked him to wear his sclerals for an entire day and we saw him after 9 hours of continued wear. This is plenty of time to check initial symptoms of any clear complication. We observed that the patient had a localized redness exactly where the pinguecula was in both eyes. The patients referred comfort with both lenses despite the redness, he just mentioned that the redness was localized nasally and he was worried about that, he usually have both eyes red with or without wearing lenses. The main difference was that when he manifested redness with the hybrid lens a year before it was the entire eyes and now it was a very localized problem.

After 9 hours of consecutive scleral lens wear of his new lenses he presented these aspect shown in figures 7 and 8. We also made an interesting new approach to the obstacle which was preventing an ideal fit, the pinguecula.

A comprehensive approach to the pinguecula We made a careful examination of both nasal conjunctiva to check the elevation of each pinguecula to have a better understanding of how it was affecting the lens fit. The figures 9a and 9n shows a slit lamp cross section view of the problem. It is important to mention that sometimes the front view simply will not give you a real idea of what is really happenning under the lens or even at the sclera alone. With these slit lamp cross section white beam with the patient turning his eyes temporally you may observe and estimate the conjunctival elevation (Figures 9a and 9b). I also made an attempt to obtain a 3D like image of the pinguecula at the left eye which in this case was the worst problem (Figure 10).

Figure 9a: Nasal scleral elevation (OD)

Fig. 9b: Nasal scleral elevation (OS)

At this time I remembered the article I read from my friend and inspirer Dr. Gregory W. Denaeyer in which he wrote about how to avoid obstacles going around them. I had the idea to go round but over it and not by side. It is interesting but after start fitting scleral lens in 2008 and today with several scleral and semi-scleral lens fitting after I read Dr. Denaeyer article we faced new challenging cases which I hope I will be able to share in the near future.

Adopting this new approach to understand the scleral and conjunctival irregularities became an obsessive part of the case, the idea was to study it deeply and find out the best way to overcome this obstacle, be it working around or over it without compromising the ideal lens fit. Unfortunately there is no technology available to achieve such information so you can only count with what you see and the ideas that may come up from guessing, but it is possible to estimate what is necessary based on the images you take and the scleral lens design if you know exactly the parameters.

The image of fig.10 was taken with a special macro lens adjusted to obtain a perspective view of the area beyond the cornea from the point of view of the cornea apex. I used a 13.6 megapixel camera with full capacity and tried to keep the light and filters at its best to acquire the best possible view of the valley beyond the cornea in a perspective line of view from the cornea apex.

Fig. 10: An attempt to estimate the necessary measures to contour the obstacle.

Final ajustments to the scleral lenses - Day four We decided to make a few adjustments to the lens at the laboratory. The idea was to make a new lens with a non-rotationally symetrical haptic which would overcome and gently countour the pinguecula without constricting it. It is important to say that without the help of our team at IOSB and also from the Ultralentes team this task would be never possible. It is of somewhat importance to have a good support and relationship with the technicians as great part of the fitting success will come from them. Figures 11a and 11 b shows the modifications done.

Fig. 11a: Elevated haptic with a dot mark.

Fig. 11b: A non-rotationally symetrical design

Testing the customized haptic scleral lens - Day five The patient received his lens back at the end of day four and wore them 7 hours the next day, came to a last follow-up before going to the airport. He presented a better conjunctival response, both lenses were working. It is important to mention again that this patient had spontaneous redness even before his visit with us and scleral lens fitting. The scleral lens presented a better vision, great comfort and his hyperemia was reduced significantly. The only problem we faced was the localized constriction of the pinguecula which was corrected using an ultra-customized approach to overcome and contour the obstacle. Both lenses have minimal movement, allow ventilation through the high permeable material and the renovation of the preservative free, saline solution of the liquid lens reservoir by spontaneous fluid exchange. Figures 12a to 12d shows the new design fit at the day five after 7 hours of continued wear. His eyes were still a bit red from the day before at this final day.

Fig. 12a: Right eye, nasal side

Fig. 12b: Left eye, nasal side.

Fig, 12c: Front view of lens, acceptable (OD).

Fig. 12d: Front view of the lens, acceptable (OS)

The final lens were perfectly acceptable for the patient, he insisted to get his flight wearing his lenses but we discourage him in order to slowly increase wearing time and then come to a follow-up visit which happened one month after his visit.

Follow-up visit - 15 days after initial day The patient came for a follow-up visit 15 days after the lens dispensing, he reported to be fine wearing his lenses for about 14 hours a day, he also reported that the right eye still presents a light redness which disappear 30 to 45 minutes after lens removal. He mentioned also that he not instilling the preservative free tears that was prescribed accordingly, he said he only used the lubricants when he thought he would need, we reinforced the need of using it more often even if he thought that it would not be necessary.

Fig. 13: Right eye, after 15 days wearing the customized Ultraflat SB

Fig. 14: Left eye, after 15 days wearing the customized Ultracone SB.

This was really a challenge case due to the short space of time to find out a solution for the patient. When he first contact us by telephone and email we never thought about any obstacle to scleral lens if the case. Dr. Marcelo and I never imagined that this would turn into this because we had access only to his topography and history before his visit

Conclusion It is possible to overcome most obstacles with scleral lenses when you face irregular cornea conditions but in cases like this when you face scleral obstacles it may be necessary to go further and make significant modifications to the lens design in order to customize and create a solution that will allow the fit. You need in cases like this to create a solution based on what you see, observing from other angles every details need to be come up with the best possible solution. It is very time consuming, not only chair time but evaluation of the case images and the time you will spend talking to the technician at the lab.

It is also important to adjust the fees you charge, these cases may not be solved by the doctor next door so you can and you deserve to be paid accordingly. The patient will be willing to pay the fees you charge no matter what if you come up with a solution. This is the case in which he count on you as a light on the tunnel, you only need to be sure that the light is not a train coming in your direction.

Luciano Bastos, FSLS Dr. Marcelo Bittrencourt, OD Ultralentes Rua Dr. Flores, 323 - Sobreloja Centro - Porto Alegre - RS + 55 51 3227.4410 / + 55 51 3028.7710 ultralentes@ultralentes.com.br

Bearwalden Business Park Wendens Ambo Saffron Walden Essex CB11 4JX Great Britain Tel: +44(0) 1799 544400 Fax: +44(0)1799 543000 professionalservices@contamac.com

806 Kimball Avenue Grand Junction, CO 81501 Tel: 1-(970) 242 3669 Fax: 1-(970)243 5501 Toll Free: 1-866 US CONTAMAC (1-866 872 6682) professionalservices@contamac.com

Notes

Bearwalden Business Park Wendens Ambo Saffron Walden Essex CB11 4JX Great Britain Tel: +44(0) 1799 544400 Fax: +44(0)1799 543000 professionalservices@contamac.com

806 Kimball Avenue Grand Junction, CO 81501 Tel: 1-(970) 242 3669 Fax: 1-(970)243 5501 Toll Free: 1-866 US CONTAMAC (1-866 872 6682) professionalservices@contamac.com