Rapid Assessment of Avoidable Blindness and Diabetic Retinopathy in Gilan Province,Iran

Purpose: To conduct an assessment of avoidable blindness and diabetic retinopathy (DR) in Gilan, 2014.

Methods: A cross-sectional population-based survey was performed on a representative sample of urban and rural individuals aged ≥50 years of the province. Blindness was defined as presenting visual acuity (PVA) <3/60 in the better eye. Moderate visual impairment (MVI) and severe visual impairment (SVI) were defined as 6/60 ≤ PVA <6/18 and 3/60 ≤ PVA <6/60 in the better eye, respectively. Diabetes mellitus (DM) was determined based on random blood sugar (RBS) levels ≥200 mg/dL or a previous diagnosis. We used the Scottish grading system to grade DR.

Results: We invited 2975 individuals from 85 clusters. Age- and sex-adjusted prevalence and 95% confidence interval (CI) of blindness, SVI, MVI, and DM in 2587 participants (response rate: 86.9%) were 1.5% (95% CI: 1.1–2.0), 1.5% (95% CI: 0.9–2.0), 11.3% (95% CI: 9.9–12.7) and 21.4% (95% CI: 19.2–23.7), respectively. The leading causes of blindness were cataract (47.1%), age-related macular degeneration (14.7%) and DR (8.8%). Cataract surgery (CS) coverage was 69.3%. The main challenges for CS were cost and unawareness. The outcome of CS was good in 66.9% of operated eyes. Any DR and/or maculopathy were observed in 25.3% (95% CI: 21.0–29.5) of subjects including 12.6% (95% CI: 9.7–15.6) sight-threatening DR. In previously known DM cases, 215 (41.7%) had never undergone an eye examination for DR.

Conclusion: The proportion of avoidable blindness and DR is considerable in Gilan Province.