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

Bhim B Rai,1,2 Phuntsho Dorji,2 Ted Maddess1 1John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia; 2Department of Ophthalmology, JDW National Referral Hospital, Thimphu, BhutanCorrespondence: Bhim B Rai, Building 131, Garran Road, John Curtin School of Medical Research, Australian National University, Canberra, ACT, 2601, Tel +61 2 61259253, Email [email protected]: 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, fluorescein 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.Keywords: anti-VEGF, avoidable blindness, complications of diabetes and hypertension, retinal vein occlusion in Bhutan, risk factors of retinal vein occlusion, vitreoretinal disease in Bhutan