Abstract
Purpose :
To gain a broader understanding of the effect on visual function, through the evaluation of contrast sensitivity, of the glare caused by exposure to different light sources at nighttime.
Methods :
An experimental study was carried out to evaluate contrast sensitivity (CS) at low (1.5 cycles/degree) and high (12 cycles/degree) spatial frequency using the FACT test in a mesopic environment under three light conditions: no glare (baseline) and two glare sources of different intensity: 0.17 lux (glare condition 1) and 0.23 lux (glare condition 2), which are within the spectrum car interior ambient lighting. In addition, measurements were made to evaluate pupil diameter without glare (baseline). The de Boer questionnaire was also used for the subjective assessment of discomfort glare. Subjects over 18 years old without eye diseases were included.
Results :
Forty subjects were recruited with a mean age of 43.39 years and a mean spherical equivalent of -1.37 diopters. The mean mesopic pupillary diameter was 6.83 millimeters. High-frequency CS scores were larger than low-frequency CS scores in the baseline and glare 2 conditions. Although no overall significant differences in high- or low-frequency CS scores were found among no glare, glare 1 and glare 2 conditions, age was found to significantly explain differences in high-frequency CS scores between the no glare and glare condition 1 (p = 0.027), and in high-frequency CS scores between no glare and glare 2 condition (p = 0.046). No significant differences in discomfort glare measured by the de Boer scale were found between glare condition 1 and 2.
Conclusions :
Low-intensity illuminations, typical of ambient car lighting, appear not to cause either considerable visual impairment nor perceived discomfort glare globally. However, the role of disabling glare caused by ambient lighting in elderly drivers should be further investigated.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.