ANGLE-CLOSURE GLAUCOMA: HOW TO APPROACH THE WORLD’S LEADING CAUSE OF IRREVERSIBLE BLINDNESS?

Nathan Congdon, MD, MPH

I. The Scope of the Angle-Closure Problem

A. Glaucoma the 2nd-leading cause of blindness in the world
B. ACG very common among very large Asian populations
C. Blindness rate 3-4X higher for PACG than for POAG
D. Due to these two factors, ACG may be second-leading cause of blindness in the world, leading cause of irreversible blindness7

II. Screening for Angle-Closure

A. Standard: Gonioscopy

1. Advantages: Relatively low tech, can be taught to non-physician, “gold standard”
2. Disadvantages: Expense (requires slit-lamp), highly subjective
3. Alternatives: “biometric gonioscopy”

B. Low tech: Flashlight test, Van Herrick

1. Both are inexpensive (though van Herrick requires slit lamp), relatively easy to learn
2. Controversy about whether these techniques are sufficiently accurate

C. “Intermediate tech”: Ultrasound A scan, pachymetry

1. Disadvantage: measuring only the central and not peripheral angle
2. Some evidence that screening performance still quite good11

D. High tech: UBM, Scheimpflug, OCT

1. The jury is still out on cost/benefit ratio for these devices

E. Need for population-based studies to demonstrate the benefit of screening and treatment

III. Treating Angle-Closure

A. Traditional approach: laser versus surgical PI

B. Various alternatives

1. Drop therapy
2. Lens extraction
3. Gonioplasty/iridopolasty15
4. Paracentesis

C. Need for more information on potential complications, cost-befit of traditional Rx (cataract, glare, etc.)

IV. Population Trends in Chinese Eyes and the Future of Angle-Closure

A. Evidence for a cohort effect in myopia among Chinese/Asiatic populations
B. Possible implications for ACG epidemiology in the future
C. Alternative explanations for the cross-sectional data we observe in Chinese populations today

 

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ENDNOTES

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