Recovery time from glare and contributing factors determined using a screening instrument in vehicle drivers.

Abstract

PURPOSE: To quantify recovery time (GRT) and assess the factors that affect this variable. METHODS AND MATERIALS: The study population was comprised of 117 subjects aged 18 to 86 year. The following optometric measurements were made in each subject using the Ergovision instrument from Essilor. GRT, static, dynamic, photopic and mesopic visual acuity (VA), contrast sensitivity, colour vision and binocular vision. GRT was determined by 10s of exposure to a glare source followed by measurement of the time taken to recover normal vision. Photopic and mesopic VA were measured at 100 cd/m2 and 2 cd/m2 respectively. Dynamic measurements for VAs of 0.1, 0.2 and 0.3 were taken at 30, 60 and 120 m/S. Colour discrimination was estimated using the Ishihara test, contrast sensitivity using sinusoidal gratings and binocular vision was assessed by establishing phorias, fusion and stereopsis. Sbujects used their habitual correction to perform the tests. The sample was stratified by age for the statistical analyses performed using Stratgraphics v5.1 sofware. RESULTS: The mean GRT was 35, with values for the different age groups. The visual factor found to affect the GRT were: the different VA measures and contrast sensitivity, all these showing significant differences. CONCLUSION: The recovery time from glare is influenced by age, VA and contrast vision.