Visual outcome of retinal vein occlusion in patients residing at high altitude.

OBJECTIVE: To study visual outcome in patients of high altitude retinopathy presenting with retinal venous occlusion. METHODS: The randomised clinical trial study was conducted at the Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan, from January 2013 to December 2015, and comprised eyes of lowlanders. Patients staying at high altitude (>8,000 feet above sea level) as part of their service duty and presented with retinal venous occlusive disease were included. Patients with history of diabetes, hypertension, glaucoma, any pre-existing retinal disease or age-related conditions responsible for decreased vision were excluded. Detailed ocular as well as systemic examination was carried out to establish the diagnosis of retinal venous occlusion. Patients were divided into two groups. First group was observed over a period of 6 months and labelled as control group, whereas the second group was treated with intravitrealbevacizumab and labelled as intervention group. Complete ocular examination was carried out in all patients at 4 weeks, 3 months and 6 months. SPSS 21 was used for data analysis. RESULTS: A series of 32 eyes of 28 male patients were included. The overall mean age was 31.40±3.40 years. The mean altitude of their temporary stay was 4,120±941 metres above sea level and the mean duration of stay was 6.80±4.13months. Besides, 21(75%) subjects were smokers. Moreover, 26(81.25%) eyes had central retinal vein occlusion while branch retinal vein occlusion was seen in 6(18.75%) eyes. The mean visual acuity in the control group was 0.70±0.56 on Logarithm of the Minimum Angle of Resolution chart at the presentation while it was 0.26±0.87, 0.20±0.32 and 0.15±0.23 after 4 weeks, 3 months and 6 months, respectively. The mean best corrected visual acuity in intervention group was 0.68 ± 0.46 before treatment and 0.15±0.11, 0.12±0.11 and 0.10±0.08 at 4 weeks, 3 months and 6 months, respectively. Significant post-intervention change was observed in best corrected visual acuity at 6 months (p<0.05) in patients who presented with severe visual loss. CONCLUSIONS: Treatment with intravitrealbevacizumab may be considered in patients with severe visual loss at presentation.