Optometry Research Today is a free monthly online journal that collates and summarizes the latest research about Optometry, including details on myopia, optometric practice, therapy.

Glaucoma and fitness to drive: using binocular visual fields to predict a milestone to blindness.

Owen VM, Crabb DP, White ET, Viswanathan AC, Garway-Heath DF, Hitchings RA

Department of Optometry and Visual Science, City University, London, United Kingdom.

PURPOSE: To use binocular integrated visual field (IVF) measures to predict which patients will lose visual function to a level below the legal standard for driving. METHODS: Data from patients attending a glaucoma clinic were collected longitudinally. The time from baseline until failure to meet the criteria of the driver's license test was modeled with Cox regression. Visual field status at baseline and visual field deterioration rate at 2 years from baseline for various monocular and binocular VF indices were investigated as predictor variables. The model that provided the best fit to the data was validated using bootstrap resampling. RESULTS: Of the patients, 20% (60/299; 95% confidence interval, 16%-25%) failed to meet the visual field criteria to prevent driver's license loss during an average follow-up of 7 years. The median age of patients was 64 years. The binocular IVF measurements gave a better fit to the observed data than the monocular measurements. Initial average visual field sensitivity and rate of visual field loss of sensitivity were significant predictors of failure to meet driver's license test criteria. CONCLUSIONS: The IVF provides a method by which binocular visual fields can be incorporated into patient management and allows, for example, a prediction of future driver's license loss. The rate of binocular IVF sensitivity loss at 2 years of follow-up may help identify patients who could benefit from intensified intervention.

Published 2 June 2008 in Invest Ophthalmol Vis Sci, 49(6): 2449-55.
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