Authors: Harrison Watt, Ali Salimi, Cody Li, John Galic, John Chen, Jesia Hasan, Hady Saheb. McGill University.

Author Disclosure Block: H. Watt: None. A. Salimi: None. C. Li: None. J. Galic: None. J. Chen: None. J. Hasan: None. H. Saheb: None.

Abstract Body:

Purpose: The prevalence of primary angle closure glaucoma (PACG) in patients with central retinal vein occlusion (CRVO) is reported to be between 0% and 9%. Multiple studies have attempted to establish the directionality of this potential association, but there is yet to be a consensus in the literature. To that end, the purpose of the current study is to compare the prevalence of angle-closure in eyes with retinal vein occlusion (RVO) to control eyes, as well as to assess the possible association between angle-closure and RVO.

Study Design: This prospective, blinded case-control study included patients with a history of RVO (case group) and patients with other retinal diagnoses (control group), matched by age (within the same decade) and manifest refraction (within 1 Diopter of spherical equivalent).

Methods: Clinical characteristics and angle-based structures derived from anterior segment ocular coherence tomography (AS-OCT)were assessed and statistically compared between the two groups, with alpha set at 0.05 for statistical significance.

Results: According to an a priori sample size calculation, a total of 64 patients (32 per group) were included. The average age of the RVO and control groups was 58.09±12.20 years and 59.41±9.62, respectively (p=0.634). There were no significant differences between the clinical characteristics of the two groups, including intraocular pressure(p=0.535) and Shaffer gonioscopy grading (p=0.632). None of the AS-OCT-derived angle characteristics were significantly different between the two groups. The number of angle-closure diagnoses did not significantly differ between the two groups. Comparison of the AS-OCT-derived angle characteristics of RVO eyes to their contralateral non-RVOeyes did not reveal any significant differences.

Conclusions: The present prospective, blinded, matched case-control study did not evidence any significant differences in clinical and AS-OCT-derived structural measures between the RVO and control eyes. Additionally, there were no structural differences between the RVO eyes and their contralateral non-RVO eyes. Collectively, these findings refute the evidence suggesting an association between primary angle-closure mechanisms and RVO.