Pattern and Prevalence of Retinal Vein Occlusion in Bhutan: A 3-Year National Survey at Vitreoretinal Clinics

Purpose: We conducted this study to determine the pattern and prevalence of retinal vein occlusion (RVO) in Bhutan to inform national health policy as no data has been compiled previously. Methods: A retrospective cross-sectional survey was conducted over 3 years, including all new RVO cases. For patients with bilateral RVO, one eye was chosen randomly. Demographic, clinical, and diagnostic details, including optical coherence tomography, f luorescein angiography, and fundus photography, were collected. Results: Of 141 RVO new patients included, aged 50.5 ± 20.2 years, there were more males (62.4%) than females (37.6%) significantly (p = 0.031), and 59.6% of total patients were from an urban setting. Farmers were the most affected group (44, 31.2%), followed by housewives (34, 24.1%), and the working group (33, 23.4%). Blurry vision (64, 45.5%), sudden loss of vision (17, 12.1%), including unsatisfactory cataract surgery (8, 5.7%) were common presenting complaints. Systemic hypertension (HT) (36, 25.5%), and diabetes mellitus (DM) (17, 12.1%), were associated systemic diseases. The prevalence of RVO was 4.8% (141/2913 all new retinal patients over the survey). Branch RVO (BRVO) was the most common type (77, 54.6%), followed by central RVO (CRVO) 56, (39.7%), and hemi-central RVO (HCRVO) (8, 5.7%). Superotemporal BRVO was the most common subtype (30, 39%) followed by inferotempoal (19, 24.7%). Best correct visual acuity (BCVA) was worse than 6/60 in 38 eyes (25.5%). BCVA was not significantly different between BRVO and CRVO eyes. Intraocular pressure was significantly lower in HCRVO eyes (p = 0.015) compared to BRVO and CRVO eyes. Conclusion: In Bhutan, 8.5% of RVO patients were bilateral. HT was associated significantly as a risk factor. Incidental findings of RVO during routine eye check-up and evaluating for unsatisfactory cataract surgery were common. Therefore, Bhutan needs to control noncommunicable diseases such as diabetes and HT to reduce RVO, and RVO-related blindness and complications.