Randomized Crossover Trial Evaluating the Impact of Senofilcon A Photochromic Lens on Driving Performance.

Significance: The first contact lens to incorporate a photochromic additive was cleared by the U.S. Food and Drug Administration last year. Because any ophthalmic lens that absorbs visible wavelengths will reduce retinal illuminance, it is important to understand the impact of this new photochromic contact lens on vision and both daytime and nighttime driving performance.

Purpose: The purpose of this study was to evaluate the effect of senofilcon A photochromic contact lens wear on vision and driving performance under real-world conditions by comparison with a nonphotochromic contact lens and plano photochromic spectacles.

Methods: In this randomized four-visit bilateral crossover study, 24 licensed regular drivers and established wearers of soft contact lenses were enrolled. Subjects wore in random order each of three study lens types: the investigational photochromic soft contact lens (test), a nonphotochromic soft contact lens (control 1), and plano photochromic spectacle lenses (control 2). Driver performance was assessed on a closed-circuit driving track under challenging controlled conditions. The primary endpoint was overall driving performance score calculated as a composite Z score of six objective metrics.

Results: All 24 subjects (mean age, 29.8 years) completed the study. For nighttime driving, the adjusted mean differences in Z score (95% confidence interval) between test and control 1 and between test and control 2 were 0.069 (-0.045 to +0.183) and 0.117 (0.003 to 0.231), respectively. For daytime driving, mean differences were 0.101 (-0.013 to +0.216) between test and control 1 and 0.044 (-0.070 to +0.158) between test and control 2. Results demonstrated noninferiority of the test lens relative to controls for nighttime and daytime driving performance using a noninferiority margin of -0.25 Z score. Noninferiority was also demonstrated on all logMAR and contrast threshold testing. No adverse events were reported during the study.

Conclusions: Study results revealed no evidence of concerns with either driving performance or vision while wearing photochromic contact lenses.