Rapid assessment of avoidable blindness: Prevalence of blindness, visual impairment and diabetes in nuevo leon, Mexico 2014

Purpose: To estimate the prevalence of blindness, visual impairment, diabetes mellitus, and diabetic retinopathy in patients aged 50years and older in the State of Nuevo Leon, Mexico. Methods: Ninety-one clusters of 60 people aged 50+ were selected randomly and a rapid assessment of avoidable blindness (RAAB) was conducted. Participants had their visual acuity and cause of visual impairment assessed, underwent a random glucose test and fundoscopy under mydriasis if they had diabetes. The diabetic retinopathy (DR) degree was classified according to the Scottish diabetic retinopathy grading scheme. Results: From the sample 5,055 (92.6%) people were examined. The blindness prevalence was 1.7% (95% Confidence Interval: 1.3-2.1%). Cataract (32.6%), DR (29.1%) and glaucoma (16.3%) were the leading causes of blindness. The prevalence of severe, moderate, and early visual impairment was 1.0%, 5.1%, and 7.7%, respectively. Among respondents, 31% had diabetes and 8.1% of them was not diagnosed prior to the study. Of all participants with diabetes, 50% had glucose levels of 200 mg/dl or higher and 15.7% had sight-threatening diabetic retinopathy. Conclusions: Besides strengthening of cataract intervention activities, more ophthalmic services for diabetic retinopathy and glaucoma control are needed in Nuevo Leon to provide timely intervention to prevent blindness.