Defective Temporal Window of the Foveal Visual Processing in High Myopia

PURPOSE: To investigate the temporal characteristics of visual processing at the fovea and the periphery in high myopia. METHODS: Eighteen low (LM, ≤ −0.50 and > −6.00 D) and 18 high myopic (HM, ≤ −6.00 D) participants took part in this study. The contrast thresholds in an orientation discrimination task under various stimulus onset asynchrony (SOA) masking conditions were measured at the fovea and a more peripheral area (7°) for the two groups. An elaborated perceptual template model (ePTM) was fit to the behavioral data for each participant. RESULTS: An analysis of variance with three factors (SOA, degree of myopia and eccentricity) was performed on the threshold data. The interaction between SOA and degree of myopia in the fovea was significant (F (4, 128) = 2.66, P = 0.036), suggesting that the masking effect had different temporal patterns between the two groups. The temporal profiles for the two groups were derived based on the ePTM model. The peak and the spread of the temporal window in the fovea were much lower and wider, respectively, in the HM group than that in the LM group (both Ps < 0.05). There was no significant difference in the peripheral temporal window between the two groups. CONCLUSIONS: High myopia is associated with defective temporal processing in the fovea, captured by a flattened temporal window.