Temporal vision adaptation and restoration in achromatopsia

Temporal vision is stronger under photopic conditions, as cones respond faster than rods, quantifiable via the temporal contrast sensitivity function (tCSF). We examined how the visual system adapts to congenitally slowed input in complete CNGA3/B3 achromatopsia (ACHM), a cone dysfunction forcing lifelong rod reliance, and whether gene therapy restoring cone function improves temporal resolution. Temporal vision was measured in 8 controls, 7 untreated ACHM, and 4 treated ACHM (3 adults and 1 child) under photopic and scotopic conditions, assessing tCSF maximal sensitivity, peak frequency, and flicker fusion frequency (FFF). Controls showed higher values under photopic than scotopic conditions. In untreated ACHM, photopic maximal sensitivity and FFF resembled controls’ scotopic values, while peak frequency matched controls’ photopic tuning. Among treated ACHM, only the child showed FFF approaching control levels. These findings suggest adaptive peak temporal tuning despite rod-limited resolution and indicate that treatment in childhood may restore temporal resolution.