Induced glare testing — an underutilized test in evaluating visual disability in patients presenting with symptomatic cataracts

Abstract

Background: Cataract increases intraocular light scatter which affects the retinal image contrast and sensitivity. Symptomatic patients with cataract complain of a drop in the quality of vision or glare affecting daily routine even with preserved visual acuity. This study was aimed to quantify the drop in the glare induced visual acuity (VA) and contrast sensitivity (CS) in different morphological types of cataracts. Material and methods: This was an observational study on a prospective cohort, conducted at a tertiary-care centre in South-India. Patients admitted for cataract surgeries between March and September 2017 with BCVA ≥ 6/60 (Snellen) and ≥ 40 years were enrolled. LogMAR VA and CS were measured pre and post-operatively, with and without glare induction using brightness acuity tester. Patients were sub-categorised based on morphology and the presence of glare as a symptom. Paired-t test for the pre- and post-operative values and analysis with Bonferroni’s adjustment were the statistical methods used. Results: Data of 78 patients were sub-categorised and analysed. Glare induction with high glare was significant in all the studied groups. LogMAR VA was affected most in group 3 (0.20, 10 letters, p < 0.05) and the CS in group 2 (0.62, 4.1 step drop, p < 0.05). Patients who had glare as a symptom had an average greater drop in LogMAR VA (0.30, p = 0.01) and CS (–0.29, p = 0.03) when induced with a high glare. Conclusions: All morphological types of cataracts affect VA and CS to a greater extent in conditions of bright lighting. Glare induced VA and CS testing is a sensitive and an adjunct tool to traditional high contrast VA testing, in evaluating the visual dysfunction of patients presenting with symptomatic cataracts.