[Validation study on self-reported visual impairment among undergraduate students at the Federal University of...

The objectives of the study were to assess the prevalence of self-reported visual impairment among undergraduate students between 18 and 39 years of age at the Federal University of Pelotas, and to validate a question about visual impairment in a subsample of the participants. A cross-sectional study was conducted by asking the question "Do you have any difficulty seeing up close and/or in the distance?" As the gold standard for the validation study, visual acuity (VA) was measured using the Snellen chart. Patients with VA less than 20/40 in either eye were considered to have reduced VA. The prevalence of self-reported visual impairment was 37.3% (95% CI: 35.1-39.6) and VA less than 20/40 in either eye was 6.9% (95% CI: 5.3-8.9). The question revealed sensitivity of 71.4% (95 CI: 57.8-82.7), specificity of 66.9% (95% CI: 63.4-70.2), positive predictive value of 13.8% (95% CI: 10.0-18.3), and negative predictive value of 96.9% (95% CI: 95,1-98.2). The results indicated a high prevalence of self-reported visual impairment among university students. The question showed reasonable sensitivity and specificity and high negative predictive value and may be used for screening for ophthalmological evaluation among young adult university students.