Abstract
Purpose :
Primary angle-closure glaucoma (PACG) affects 20 million people worldwide. People classified as primary angle closure suspects (PACS) have a higher but poorly quantified risk of developing glaucoma. Laser peripheral iridotomy (LPI) is widely practiced as prophylaxis against PACG but its efficacy is unproven.
Methods :
In this randomized controlled trial, 11,991 participants aged between 50 and 70 years were screened in the community from Guangzhou, China. People with bilateral PACS were enrolled and received LPI in one randomly selected eye, with the fellow remaining untreated. The primary outcome was incident primary angle closure disease as a composite endpoint of elevation of intraocular pressure, or peripheral anterior synechiae, or acute angle-closure during 72 months of follow up.
Results :
Of the 889 subjects who underwent randomization, 889 treated and 889 untreated eyes were included in the intention-to-treat analysis. The incidence rate of primary outcome was 4.2 per 1,000 eye-years in treated eyes versus 8.0 per 1,000 eye-years in untreated eyes (HR 0.53, 95%CI: 0.30–0.92). A primary outcome event occurred in 19 treated eyes and 36 untreated eyes with a statistically significant difference using pair-wise analysis (p=0.004). No serious adverse events were observed during follow up.
Conclusions :
The risk of incident angle-closure disease was very low among individuals with PACS identified through community-based screening. LPI had a modest, albeit significant, prophylactic effect. In view of the low incidence rate of outcomes that have no immediate threat to vision, the benefit of prophylactic LPI is limited and thus it should only be offered to those with the highest risk of PACG. (ISRCTN45213099).
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.