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Baskaran Mani, Rajesh Sasikumar, Hon Tym Wong, Paul Chew, Paul J Foster, David S Friedman, Tin Aung; The Singapore Asymptomatic Narrow Angles Laser Iridotomy Study (ANA-LIS): 5-year results. Invest. Ophthalmol. Vis. Sci. 201657(12):.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the 5-year progression rate to primary angle closure (PAC)/primary angle closure glaucoma (PACG) for subjects with bilateral asymptomatic narrow angles who were randomized to prophylactic laser peripheral iridotomy (LPI) in one eye versus no treatment in the fellow eye.
This multi-center (3 Singapore sites), interventional RCT (NCT00347178, Clinical trials.gov) enrolled 476 subjects over the age of 50 years who were diagnosed as bilateral asymptomatic primary angle closure suspects (PACS), with ≥2 quadrants of appositional angle closure on gonioscopy. Each subject underwent prophylactic LPI in one randomly selected eye, while the fellow eye served as a control. Outcome measures included progression to symptomatic angle closure, or the development of PAC (defined as presence of peripheral anterior synechiae (PAS), and/or raised intraocular pressure) and/or PACG (with glaucomatous optic disc changes and corresponding visual field loss on automated perimetry). Cox proportional-hazards regression was performed after adjusting for variables such as age, sex, cataract surgery and retinal vascular occlusive events.
Of the 476 subjects randomized, the majority were Chinese (93.5%) and female (76.3%) with mean age of 62.8±6.9 years. At the end of 5-years of follow up, progression was found to be significantly higher in the non-LPI eyes [46 (9.8%, 95% CI: 7.2, 12.7) vs 23 (4.8%, 95% CI: 3.1,7.2) LPI eyes, p<0.0001, McNemar test]. Overall, eyes with progression included, PAC - 56 (PAS – 34; PAS/raised IOP – 22), acute attacks – 2, PACG – 7 and symptomatic angle closure – 4. Both the acute attacks occurred in the non-LPI eyes. The adjusted hazards ratio for progression to angle closure disease was 1.98 (95% CI: 1.2, 3.25, p=0.008) in non-LPI eyes compared to the eyes that underwent LPI. Older subjects (HR: 1.07, 95% CI: 1.04, 1.1, p<0.0001) and female sex (HR: 1.8, 95% CI: 1.1, 2.95, p=0.02) had higher risk of progression. The number needed to treat (NNT) in order to prevent progression was 20.7 (95% CI: 12.33, 64.43).
In subjects with bilateral narrow angles, eyes that underwent prophylactic LPI had significantly less progression compared to those who did not undergo LPI over 5 years.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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