Abstract
Abstract: :
Purpose: Aim of the study was to develop a valid rapid assessment technique, designed to be a cost– and time effective tool to evaluate changes in eye health status and behaviour affecting public eye health promotion campaigns. Methods: A small number of key indicator rates were selected. The sample size calculation was based on sufficient power (80%) to detect a 50% reduction in the prevalence of undiagnosed glaucoma, the least frequent of the key indicators. Participation was volunteer–based and recruitment was by mail. Selected participants were representative of the socio–economic structure of Melbourne. Participants with VA<6/12 best–corrected VA were auto refracted. Anterior segments and fundi were photographed with a digital non–mydriatic fundus camera. Visual fields were tested with Frequency Doubling Technology. Glaucoma diagnosis was based on history, visual field analysis (two or more points missed) and optic nerve head assessment (C/D ratio >0.6). Outcomes were compared with the Melbourne Vision Impairment Project (VIP). For each binary outcome, the percentages and their confidence intervals in the studies were calculated by fitting the logistic regressions without covariates for this outcome to the data. Results: Of the 1695 participants (aged 70–79 years), 8% were visually impaired, compared to 10% in the VIP for the same age group. The main causes of visual impairment were un– or under corrected refractive error (73%, VIP 66%; p=0.34), AMD (13%; VIP 8%; p=0.38), cataract (11%, VIP 10%; p=0.82), DR (2%, VIP 0%; NS) and glaucoma (1%, VIP 2%; p=0.48). The overall prevalence of glaucoma was the same in both studies (24%). Two Hundred Forty Fife people (64%) with glaucoma were previously undiagnosed. Conclusions: The rapid assessment was designed to be highly cost–effective and rely on less specialist personnel. While the prevalence rates for the main causes of visual impairment are comparable to the conventional VIP, costs of this assessment were only approximately 10% of the total VIP costs. This valid and highly effective technique will be repeated in two years to evaluate changes following the public awareness campaigns.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • low vision