Glare visual performance in young subjects under night driving conditions



Purpose Purpose: Under night driving conditions visual performance is compromised and become worse with disability glare, age and certain ocular pathologies. The aim of this study was to analyze mesopic visual function of young subjects.

Methods Methods: The sample included 37 right eyes of healthy young adults (22.2 ± 1.8 years). The selected criteria were: Best-corrected VA of at least 0.04 logMAR, and refraction ≤± 3.75. Under mesopic (0.1 to 0.2 cd/m2) luminance conditions and with the best-optical correction in the right eye, the logMAR VA was measured using high-contrast (HC-96%) and low-contrast (LC-10%) logMAR Bailey-Lovie letter charts, and the mesopic contrast sensitivity (CS) without / with glare was assessed with Mesotest II. The intraocular straylight was measured with the C-Quant.

Results Results: Under mesopic conditions, the HC and LC logMAR VA was 0.28 ± 0.1 and 0.70 ± 0.1 respectively, showing a significant correlation between them (Pearson’s correlation = 0.75; p< 0.00); The mesopic log CS without glare was 0.19 ± 0.1 and with glare was 0.11 ± 0.1. Disability glare induced a 42% decrease in mesopic log CS (p < 0.00). LC logMAR VA was significant correlated with mesopic log CS without and with glare (Pearson’s correlation = 0.4, p< 0.02, and 0.42, p< 0.02 respectively). The intraocular straylight Log (s) was 0.87 ± 0.1, but did not show any significant association with logMAR VA nor the log CS without and with glare under mesopic luminance conditions.

Conclusion Conclusions: The results indicated that mesopic assessment of the low contrast logMAR VA and log CS without and with glare might potentially predict the glare visual performance under night driving conditions.