Cross-sectional study of the retinal nerve fiber layer thickness at 7 years after an acute episode of unilateral primary acute angle closure

The purpose of this article is to investigate the long-term retinal nerve fiber layer (RNFL) status and determinants of RNFL thinning after an episode of unilateral primary acute angle closure (AAC). This cross-sectional study analyzed the medical records of consecu- tivepatientswithasingleepisodeofunilateralAACfrom1999to2009in Hong Kong. The peripapillary RNFL thickness was correlated with age, gender, presenting intraocular pressure (IOP), time to laser iridotomy, time to cataract extraction, follow-up duration, as well as the last IOP, vertical cup-to-disc ratio (CDR), and vision. The fellow uninvolved eye was used as a proxy comparison of RNFL loss in the attack eye. In 40 eligible patients, the mean age was 68.3 � 8.7 years with a male-to-female ratio of 1:7. The mean presenting IOP was 49.2 � 14.0 mm Hg and the time from presentation to laser iridotomy was 6.7 � 6.9 days. Forty percent of subjects received a cataract extraction at 3.2 � 2.9 years after the attack. The last IOP, CDR, and LogMAR vision were 16.0 � 3.8 mm Hg, 0.6 � 0.2, and 0.6 � 0.6 LogMAR units, respectively, at 7.9 � 2.4 years. The RNFL thickness in the attack eye (69.2 � 19.1 mm) was 25.2 � 17.9% thinner than the fellow eye (93.0 � 17.8 mm) at 7.5 � 2.9 years post-AAC. Using univariate analysis, the last vertical CDR (odds ratio (OR) ¼17.2, P ¼0.049) and LogMAR visual acuity (VA) (OR ¼6.6, P ¼0.03) were the only significant pre- dictors for RNFL thinning whereas none of the other covariates showed significant associations (P >0.1). At 7.5 years following unilateral AAC, the RNFL thickness was 25% thinnerthanthefelloweye.CDRenlargementandpoorVAweretheonly significant predictors for RNFL loss.