Improvement in Visual Acuity by Refraction in a Low Vision Population

Abstract

Purpose: : Refraction may often be overlooked in low vision patients, since the main cause of vision decrease is not refractive but rather due to the underlying ocular disease. This retrospective study was done to determine how frequently visual acuity is improved by refraction in a low vision population.

Methods: : A database with all new low vision patients seen from November 2005 to June 2008 recorded presenting visual acuity using an ETDRS chart; it also recorded the best-corrected visual acuity if it was two or more lines better than the presenting visual acuity. Retinoscopy was done on all patients, followed by a manifest refraction.

Results: : 739 new low vision patients were seen, with median acuity of 20/80-2, and the 25^th to 75^th percentile range was 20/50 to 20/200. There was an improvement of >=2 lines of visual acuity in 81 patients (11% of all patients), with 22 patients (3% of all patients) improving by >=4 lines. There was no significant difference in age or in presenting visual acuity between the group that did not improve by refraction and the group that did improve. When stratified by diagnosis, the only two diagnoses with a significantly higher rate of improvement than the AMD group were myopic degeneration and progressive myopia (odds ratio 4.8 [3.0-6.7]) and status post retinal detachment (odds ratio 7.1 [5.2-9.0]). For 5 patients (6% of those with improvement), the eye that was >=1 line worse than the fellow eye at presentation became the eye that was >=1 line better than the fellow eye after refraction.

Keywords: low vision • visual acuity • refraction