Abstract
Abstract: :
Purpose:To describe the effect of amblyopia on educational level and occupational class, the 5–year incidence of visual impairment in the non–amblyopic eye, and its effect on acuity in amblyopic eyes from a population–based cohort study. Methods:3654 participants aged 49 years or older participated in the Blue Mountains Eye Study (BMES I, 1992–1994), and 2335 (75.1% of survivors) were re–examined after 5 years between 1997–1999 (BMES II). All participants underwent detailed eye examination. Amblyopia was defined in 118 participants (3.2%) in BMES I, of whom 73 were re–examined in BMES II. Occupation and educational classifications used were definitions of the Australian Bureau of Statistics. Results:Amblyopia did not affect lifetime occupational class (p=0.5), but fewer persons with amblyopia completed higher university degrees (p=0.05). The 5–year incidence of visual impairment worse than 20/40 in the better–seeing eye was 33.3% in persons with amblyopia compared with 12.5% in persons without amblyopia (RR: 2.7, 95% CI: 1.6–4.6). Cases not correctable by refraction accounted for 11.1% and 1.7% respectively. Improvement in visual acuity of the poorer–seeing eye after a 2–line (10 logMAR letter) visual loss in the better–seeing eye was significantly higher in persons with amblyopia (p=0.007), where 9.1% of persons with amblyopia improved more than 2 lines compared to 3.6% of persons without amblyopia. Conclusions:This study further documents the natural history of amblyopia. We found borderline significant effect of amblyopia on persons completing higher university degree qualifications. Consistent with recent UK data, we found a significant difference in the five–year incidence of visual impairment, and the proportion with improved acuity in the poorer–seeing eye after significant vision loss in the better–seeing eye in persons with and without amblyopia.
Keywords: amblyopia • clinical (human) or epidemiologic studies: natural history • clinical (human) or epidemiologic studies: prevalence/incidence