Drivers' ability to recognize pedestrians at night is degraded by common visual impairments, even when the drivers' mean visual acuity meets licensing requirements. To maximize drivers' ability to see pedestrians, drivers should wear their optimum optical correction, and cataract surgery should be performed early enough to avoid potentially dangerous reductions in visual performance.

ABSTRACT.Purpose: To investigate the age range for which cycloplegia provides additional information compared with non-cycloplegic refraction in teenagers and young adults. Methods: Data for 1295 subjects (704 female; 591 male) from the Twins Eye Study in Tasmania (TEST) and the Brisbane Adolescent Twin Study (mean age: 19.65 AE 3.56, range: 13-26 years) were included. For all participants, cycloplegia was induced by instillation of either one drop of 1% cyclopentolate (13-14 years) or one drop of 1% tropicamide (15-26 years). Pre-and post-cycloplegic refractive errors for both eyes were measured using a Humphrey-598 automated refractor and spherical equivalents of refractive error were calculated. Generalized Estimating Equations (GEE) were used to model the spherical equivalent refraction (SER) for each eye against age (by year) and axial length (in the given eye). Results: The mean group difference between pre-and postcycloplegic SER (post minus pre) was 0.17 AE 0.52 D and 0.12 AE 0.51 D for the right and left eyes, respectively, indicating that postcycloplegic refraction was generally more hyperopic/less myopic. The mean difference between pre-and postcycloplegic SER decreased from 0.36 AE 0.41 D in the 13-year-olds to 0.06 AE 0.50 D in people aged 25 years. After adjusting for family-relatedness, the difference between pre-and postcycloplegia SER was significant in all age groups up until the age of 20 years. Conclusions: Non-cycloplegic autorefraction can result in group mean SER differences of greater myopia than cycloplegic autorefraction and occurs in teenagers (13-19 years of age), but not in adults 20-26 years. These data suggest that cycloplegia is not required in population estimates of refractive error for young adults once they reach approximately 20 years of age.

Bicycling at night is more dangerous than in the daytime and poor conspicuity is likely to be a contributing factor. The use of reflective markings on a pedestrian's major joints to facilitate the perception of biological motion has been shown to greatly enhance pedestrian conspicuity at night, but few corresponding data exist for bicyclists. Twelve younger and twelve older participants drove around a closed-road circuit at night and indicated when they first recognized a bicyclist who wore black clothing either alone, or together with a reflective bicycling vest, or a vest plus ankle and knee reflectors. The bicyclist pedalled in place on a bicycle that had either a static or flashing light, or no light on the handlebars. Bicyclist clothing significantly affected conspicuity; drivers responded to bicyclists wearing the vest plus ankle and knee reflectors at significantly longer distances than when the bicyclist wore the vest alone or black clothing without a vest. Older drivers responded to bicyclists less often and at shorter distances than younger drivers. The presence of a bicycle light, whether static or flashing, did not enhance the conspicuity of the bicyclist; this may result in bicyclists who use a bicycle light being overconfident of their own conspicuity at night. The implications of our findings are that ankle and knee markings are a simple and very effective approach for enhancing bicyclist conspicuity at night.