Aging leads to impaired visual function, which can affect driving—a very visually demanding task—and has a direct impact on an individual’s quality of life if their license is withdrawn. This study examined the associations between age-related vision changes and simulated driving performance. To this end, we attempted to determine the most significant visual parameters in terms of evaluating elderly drivers’ eyesight. Twenty-one younger drivers (aged 25–40) were compared to 21 older drivers (aged 56–71). Study participants were assessed for visual acuity, contrast sensitivity, halos, and intraocular straylight, which causes veiling luminance on the retina and degrades vision. Driving performance was evaluated using a driving simulator. The relationships between simulated driving performance and the visual parameters tested were examined with correlation analyses and linear regression models. Older drivers presented impairment in most visual parameters (p < 0.05), with straylight being the most significantly affected (we also measured the associated effect size). Older drivers performed significantly worse (p < 0.05) in the simulator test, with a markedly lower performance in lane stability. The results of the multiple linear regression model evidenced that intraocular straylight is the best visual parameter for predicting simulated driving performance (R² = 0.513). Older drivers have shown significantly poorer results in several aspects of visual function, as well as difficulties in driving simulator performance. Our results suggest that the non-standardized straylight evaluation could be significant in driver assessments, especially at the onset of age-related vision changes.

In the last decade, the use and development of objective optical devices, such as aberrometers and double-pass devices, have expanded to evaluate the optical quality of the human eye. ^{1, 2, 3, 4, 5} With these devices, the aim is to achieve an objective evaluation of the observer's visual state, spending the least time possible in taking the data. This time savings is a great advantage in clinics, where time spent per patient is limited; also, for older patients, speed of examination avoids unnecessary fatigue in the observer. However, these optical devices were previously large and also costly, sometimes prohibitively so. Without these devices, the visual examination of the subject would be limited to the usual psychophysical tests as well as the study of the refractive state of the subject. Therefore, other subjective tests are needed that require the cooperation of the patient to characterize the visual performance of the subject. The discrimination capacity of the subject is an important visual function for this purpose, allowing us to evaluate the real state of vision of the subject and providing an easy tool for detecting potential visual dysfunctions. For these reasons, a new visual test for quantifying discrimination capacity was developed that needs no specific hardware, is free of charge, and is becoming an accessible and easy tool for clinical applications compared to former complex optical devices. On the other hand, the development of simple visual tests that evaluate visual function is an important task for the study, monitoring, and early diagnosis of different visual pathologies that develop asymptomatically to advanced stages of pathology, such as age-related macular degeneration (ARMD), and that could go unnoticed if not adequately tested. In this study, we check the visual test developed for quantifying discrimination capacity in subjects with different ocular pathologies and seek to determine whether these ocular pathologies, which affect the retinal-image quality, cause any deterioration in the discrimination capacity and, consequently, in visual performance.