Effect of fogging lenses on accommodation using an open-view portable wavefront autorefractor

Abstract

Purpose To investigate the effect of a + 2.00 D fogging lens on accommodative behavior during measurements with an open-view handheld wavefront autorefractor, considering refractive status and fogging duration. Methods Participants underwent six consecutive 10-second measurements per eye using an open-view autorefractor: three without and three with a fogging lens. Subjects were classified as myopic, emmetropic or hyperopic based on the mean spherical refraction of the right eye. Bland–Altman analysis assessed device repeatability and the effect of fogging (with vs without), both overall and by refractive group. The influence of acquisition time was evaluated by comparing the first 5 s with the full 10-second recordings. Results Sixty-one young adults (25.02 ± 6.16 years; spherical refraction -0.80 ± 2.21 D) were included: 34.4% myopes, 42.6% emmetropes and 22.9% hyperopes. Ten-second measurements showed excellent repeatability, with mean differences near zero and 95% limits of agreement within ±0.50 D, regardless of fogging. Shortening acquisition to 5 s maintained negligible bias but increased variability by ∼20%. The fogging lens induced heterogeneous responses across refractive groups. In myopic and emmetropic eyes, most showed no change (52% and 58%), and accommodative relaxation occurred infrequently (10% and 17%). In contrast, 43% of hyperopic eyes showed accommodative relaxation, with a mean refractive shift of 0.84 D, suggesting a clinically meaningful response. Conclusion The effect of a + 2.00 D fogging lens depends on refractive status. Routine use may provide limited additional benefits in myopic and emmetropic subjects, whereas hyperopic individuals appear more likely to benefit from its selective use.