Photochromic contact lenses do not impair driving performance
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The use of senofilcon A photochromic contact lens did not impair or diminish driving performance or vision, according to findings from a randomized, single-center, crossover study published in Optometry and Vision Science.
John R. Buch, OD, MS, FAAO, of Johnson & Johnson Vision Care, and colleagues enrolled 24 licensed drivers and habitual soft contact lens wearers in this study from September 2017 to December 2017. A nonphotochromic soft contact lens (Acuvue Oasys, Johnson & Johnson Vision Care) and plano photochromic spectacle lenses (Transitions Optical) were used as controls. The study lens types were worn at random by participants
“Acuvue Oasys with Transitions is just as safe for daytime and nighttime driving as other commercially available devices (non-photochromic contact lenses and photochromic spectacles),” Buch told Primary Care Optometry News. “In fact, it may provide a benefit with night driving by being able to detect a road sign at a further distance.”
Driving performance evaluation included pedestrian recognition distance, percent hazard avoidance, percentage of road signs identified correctly, sign recognition distance, percentage of time within the driving lane and lap time. Researchers assessed driving performance in a closed-circuit track in controlled conditions.
For night driving performance score, the mean difference between photochromic and the control soft contact lens was 0.069. The mean difference for daytime driving performance was 0.101 between photochromic and nonphotochromic soft contact lens and 0.044 between photochromic soft contact lens and the plano photochromic spectacle lens.
Because the mean differences were above –0.25, researchers concluded that photochromic soft contact lens were noninferior to the control lenses for nighttime and daytime driving performance. These findings were consistent on all logMAR and contrast threshold testing.
“Clinical data did not reveal any evidence of impaired or diminished driving and vision performance among participants wearing the senofilcon A-based contact lens with photochromic additive assessed during nighttime and daytime driving sessions,” Buch and colleagues wrote. “Senofilcon A lenses containing a photochromic additive may therefore be considered substantially equivalent to clear Acuvue Oasys soft contact lenses but with the benefit of light attenuation.”
Buch told PCON that doctors can prescribe the lens without concerns about driving, “just as they have with photochromic spectacles for more than 20 years.” – by Erin T. Welsh
Disclosures: Buch and his co-authors are employed by Johnson & Johnson Vision Care, which provided financial and material support in this study.
Perspective
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Clarke D. Newman, OD, FAAO
The present clinical trial evaluating a novel photochromic soft contact lens’s performance vs. a non-photochromic contact lens or a pair of photochromic spectacle demonstrated that the photochromic contact lens was noninferior to both controls in all metrics except two. In those two cases the photochromic contact lens was superior to one or both controls. In the Mesotest II test, the photochromic contact lens was superior to the photochromic spectacle control. In the nighttime sign recognition at distance test, the photochromic contact lens was superior to both controls.
These findings are important in addressing fears of adverse effects caused by decreased illuminance through a photochromic contact lens. Driving at night with a lens that might have a reduced transmission would increase driving hazards, and this evaluation of many pertinent driving metrics during day and nighttime conditions demonstrates that the photochromic lens seems not to have these drawbacks.
An important limitation of this study is that it was performed and underwritten by the manufacturer of the test contact lens. Nonetheless, this study appears to be free of bias.
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