Primary Angle Closure Mechanisms May Not Cause Retinal Vein Occlusion

Primary angle closure mechanisms are likely not associated with retinal vein occlusion (RVO), according to research published in the Canadian Journal of Ophthalmology. However, anterior chamber depth (ACD) is shallower in eyes with RVO compared with the contralateral eye in individuals with the condition, increasing the risk for intermittent or permanent pupillary block, the report shows.

Researchers included 88 patients recruited from 2 health care facilities in the prospective, case-control study and compared clinical characteristics and angle-based structures between individuals with RVO (n=44; mean age, 59.8 years; women, 24) and control group participants (n=44; mean age; 60.8 years; women, 26) who did not have RVO.

Among patients with RVO, 27 had branch RVO, 14 had central RVO, and 3 had hemi-RVO. Common diagnoses among control group participants included diabetic retinopathy (n=12), retinal tear (n=10), and posterior vitreous detachment (n=5). All study participants underwent ophthalmic assessment performed by a single glaucoma specialist and anterior segment optical coherence tomography (AS-OCT).

There were no significant differences in clinical characteristics between participants with RVO and control group individuals, the report shows, with both groups demonstrating similar intraocular pressure (P =.873), spherical equivalent (P =.681), best-corrected visual acuity (P =.482), cup-to-disc ratio (P =.399), and retinal nerve fiber layer (RNFL) thickness (P =.122). Similarly, anterior chamber width (P =.751), ACD (P =.367), and lens vault (P =.215) were comparable between the 2 cohorts.

While primary angle closure mechanisms did not demonstrate an association with RVO, eyes with RVO had a significantly smaller ACD compared with the contralateral eye (2.72 vs 2.76 mm; P =.014). The eye with RVO tended to have a smaller angle opening distance nasally at 750 mm (0.45 vs 0.51 mm; P =.051), greater RNFL thickness (98.61 vs 91.07 mm; P =.055), and smaller trabecular iris angle nasally at 750 mm (29.20° vs 32.30°; P =.057) compared with the contralateral eye.

“[W]hen comparing the AS-OCT-derived structural measures of RVO eyes with their contralateral non-RVO eyes, a shallower ACD was noted in the RVO eyes,” the study authors explain. “Although the findings suggest that an association between primary angle closure mechanisms and RVO is unlikely, the shallower ACD in RVO eyes could potentially put RVO eyes at higher risk for intermittent or permanent pupillary block.”

Study limitations include a small sample size.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.