Abstract

Aims/Purpose: Light‐adaptive lenses, known as photochromic, adjust dynamically light intake. We recently evaluated the effect of a new ultra‐responsive light‐adaptive lens on contrast sensitivity recovery during fade back compared to the older photochromic generation, showing that faster fadeback speed improves contrast sensitivity. However, data was lacking in varying light, specifically when moving from bright to dark environments, and in comparison to a static clear lens. This study assessed dynamic contrast sensitivity changes with the new light‐adaptive lens after exposure to a transient bright light, compared to the older photochromic lens and to a static clear lens. Methods: Ten healthy subjects (28.7 ± 3.4 years, spherical equivalent ‐1.8 ± 1.8 D, astigmatism < 1D) were trained to control contrast of a sinusoidal grating (24 cycles/degree) at 3 m. Three lenses were used in a double‐blind cross‐over design; a clear lens, a photochromic TO2, and a new light‐adaptive TO1, twice as fast as TO2 in returning to clear state. Subjects were exposed to a bright light (8000 lux) for 30 seconds, then transitioned to darkness where contrast sensitivity was measured dynamically for 100 seconds. Recovery times for first contrast perception and 90% contrast sensitivity were recorded for each lens, tested three times. MANOVA with Tukey tests were performed. Results: TO1 recovered 90% contrast sensitivity 35% faster than clear lens ( p < 0.01) and 23% faster than TO2 ( p < 0.01). Initial contrast perception recovery was 55% faster with TO1 compared to clear lens ( p < 0.001). Conclusions: The new light‐adaptive lens TO1 significantly improves visual performance in dynamic light conditions compared to the older photochromic lens TO2 and the static clear lens. This performance enhancement reduces light stress and improves visual function under normal viewing conditions.