GLAUCOMA
Assoc Prof Dr Sushil Kumar Vasudevan Faculty of Medicine Universiti Teknologi MARA
GLAUCOMA: A GLOBAL VIEW Prevalence1,2,3 • Glaucoma affects between 60-70 million people worldwide • Glaucoma is responsible for 12% of global blindness • Patients often diagnosed too late • Certain ethnic populations at high risk
1.
Awareness • Awareness of risk factors is low • Most people are not proactive about eye health • Glaucoma not a priority among media compared to other chronic conditions
Treatment • Challenging to diagnose and treat before vision loss has occurred • Late diagnosis has health and economic implications • Link between IOP and optic nerve damage emphasizes need for ongoing risk assessment
2.
World Health Organization. Bulletin of the World Health Organization. In Focus. Nov 1, 2004. Available at: http://www.who.int/bulletin/volumes/82/11/feature1104/en/. Accessed July 16, 2007. Congdon NG, Friedman DS, Lietman T. Important Causes of Visual Impairment in the World Today. JAMA. 2003; 290: 2057-2060.
3.
Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006; 90: 262–267 .
PEOPLE ARE LEAVING THEIR VISION TO CHANCE
1. 2.
•
50% of people with open-angle glaucoma in the developed world are unaware they have it1
•
More than 50% of people with angle-closure glaucoma are unaware they have it2
Tielsch JM, Sommer A, Katz J et al. Racial Variations in the Prevalence of Primary Open-angle Glaucoma: The Baltimore Eye Survey. JAMA 1991; 266: 369-374. Thomas R, Sekhar GC, Parikh R. Primary angle closure glaucoma: a developing a world perspective. Clinical & Experimental Ophthalmology 2007; 35(4): 374-378(5)
1. 2.
•
50% of diagnosed glaucoma patients are not treated1
•
50% of people globally have not had their eye pressure checked2
•
Nearly 50% of people over 60 have not had their eye pressure checked2
Tielsch JM, Sommer A, Katz J et al. Racial Variations in the Prevalence of Primary Open-angle Glaucoma: The Baltimore Eye Survey. JAMA 1991; 266: 369-374. All Eyes on Glaucoma Global Survey sponsored by Pfizer Ophthalmics
GLAUCOMA Second most common cause of blindness worldwide. Prevalence : 1.4 - 3.2% in population >40years Prevalence increased with age Estimated that 4.5 million persons globally are blind due to glaucoma
World Health Organization data from www.who.int/blindness/causes/priority/en/
Individuals suspected of having glaucoma or undiagnosed, far exceed the number who have already been diagnosed (substantial proportion).
Most patients present late
Causes irreversible blindness
ď‚
Up to 50% of affected persons in the developed countries are not even aware of having glaucoma, due to the silent progression of the disease (at least in its early stages)
This number may rise to 90% in underdeveloped parts of the world.
Sommer et al. Relationship between intraocular pressure and primary open angle glaucoma among white and black Americans. The Baltimore Eye Survey. Arch Ophthalmol 1991; 1090-1095
Magnitude of the problem is expected to increase in future as the population ages
Africa – largest ratio of glaucoma to population over age 40 overall, but China will have the largest absolute number
ď ś In Malaysia, the National Eye Survey of 1996 found that of 18,027 individuals, 1.77% people were blind from glaucoma and 39% were blind as a result of cataract. ď ś In Mongolia, based on population based surveys, 35% of blindness in adults was due to glaucoma (cataract cause 36% of blindness).
ANATOMY OF THE EYE
DEFINITION A progressive optic neuropathy, characterized by a characteristic optic nerve head (cupping) and visual field changes.
RISK FACTORS
PREVALENCE
Family history
0.4% < 60 years of age
Diabetes
1.3% 60 -69 years or age
Myopia (short sighted)
4.7% 80 years or older
Migraine (vasospasm) Injury or infection Race >40 yrs of age
Mitchell et al1998, Blue Mountains Study
AQEOUS HUMOUR PRODUCTION
AQUEOUS DRAINAGE
a)
Trabecular route (90%)
b)
Uveoscleral /unconventional route (10%)
-
IOP
UNDETECTABLE DISEASE MAY PROGRESS TO FUNCTIONAL IMPAIRMENT
Weinreb et al. Risk assessment in the management of patients with ocular hypertension. Am J Opthalmol. 2004;138:458-467
CLASSIFICATION Pathogenesis
Causes
Presentation
Open Angle
Primary
Acute
Closed Angle
Secondary
Chronic
Acute on chronic
OPEN ANGLE
ANGLE CLOSURE
PRIMARY
PRIMARY
SECONDARY
SECONDARY
AC angle at gonioscopy SL biomicroscopy ONH findings VF defects
Compromised TM function
Mechanical blockage at the angle
SECONDARY OAG
Pseudoexfoliative glaucoma
Pigment dispersion glaucoma
Angle recession glaucoma
Inflammatory glaucoma
Steroid induced glaucoma
Neovascular glaucoma (early)
Glaucoma associated with increased episcleral venous pressure
ISGEO CLASSIFICATION
PACS
• ITC (iridotrabecular contact) in 3 or more quadrants • Normal IOP, disc and field • No evidence of PAS
PAC
• ITC in 3 or more quadrants • Either raised IOP and/or primary PAS • Disc and field are normal
PACG
• ITC in 3 or more quadrants • Evidence of glaucomatous damage to disc and visual field
optic
MECHANISM OF ANGLE CLOSURE
SECONDARY ACG Mechanisms Pulling from anteriorly
Pushing from posteriorly
Proliferation of membrane over the angle
Iris-lens diaphragm ± peripheral iris pushed forward
Contracting membrane
Pulled iris towards angle Angle closed
± Pupillary block
Angle closed Lens induced (intumescent) Intraocular tumors (CB , iris)
NVG ICE syndrome Inflammatory
Ciliochoroidal effusion (PRP, CRVO, uveal effusion synd, choroidal h’ge, post scleral buckling, drug induced) Contracting retrolental membrane Malignant glaucoma
DETECTION & MONITORING OF GLAUCOMA
Measurement of IOP
Examination of optic nerve head
Examination of the angle
Examination of visual field
INTRAOCULAR PRESSURE MEASUREMENT
Goldman Applanation tonometer
GONIOSCOPY
ANGLE ASSESSMENT: TORCH METHOD
GRADING OF ANGLE WIDTH Essential part of the assessment of glaucomatous eyes Main aims to evaluate the functional status of angle its degree of closure risk of future closure
DIAGNOSIS AND MONITORING 1.
Structural changes (optic disc/RNFL)
2.
Functional changes (Visual field defect/changes)
TYPES OF GLAUCOMA INVESTIGATION 1. Structural - Imaging ( Optic disc, RNFL, anterior segment imaging 2. Functional - Perimetry ( SAP, SWAP, FDT)
OPTIC DISC EVALUATION Structural damage is frequently apparent before identifiable visual field loss (structural damage precedes visual loss) ď&#x201A;&#x17E;Methods : 1. Direct ophthalmoscope 2. Indirect lens (eg. 90 D/78D - stereoscopic view) 3. Stereoscopic photography
EXAMINATION OF ONH/RNFL Methods: Slit- lamp biomicroscopy with indirect lens
(stereoscopic view, dilated pupil)
Stereoscopic photography Red- free filter to view RNFL striations Direct ophthalmoscope (only assess optic nerve head)
ANATOMY OF THE OPTIC NERVE HEAD
IMAGING
Pros • Objectivity/ lack of learning effects • Repeatability/reproducibility • Usability • Quantitative Cons • Monochromatic • Largely dependent on software • Compatibility between devices
PERIMETRY
Types
Manual (Bjerrum, Goldmann)
Automated a. Static
Humphrey /Octopus
SAP (gold standard) / SWAP/ FDT
b. Kinetic
PERIMETRY ï&#x201A; Assess functional deficit of glaucoma = visual field defect
VISUAL FIELD LOSS PATTERN
Glaucomatous VF defects follow the pattern of nerve fiber loss
Characteristic VF defects because of the unique anatomy of RNFL
Paracentral
Siedel scotoma
Peripapillary atrophy
PRINCIPLE OF TREATMENT 1.
Reduce the production of the aqueous fluid
2.
Increase the drainage of aqueous through the trabecular meshwork
TREATMENT
Beta blocker Prostaglandin analogue Alpha agonist Carbonic anhydrase inhibitor
LASER TREATMENT : INCREASE THE DRAINAGE
Argon laser trabeculoplasty Selective laser trabeculoplasty
SURGERY: TRABECULECTOMY (WHEN MEDICAL THERAPY FAILS TO CONTROL IOP)
THANK YOU FOR YOUR KIND ATTENTION