Abstract
Purpose :
Adaptation to high- or low-contrast is a known process of the visual system. Moreover, adaptation, guided by retinal mechanisms, also influences refractive development. So far, central contrast adaptation has been measured centrally or peripherally after peripheral adaptation, however not centrally after peripheral adaptation. Therefore, this study aimed to investigate the short-term influence of different levels of peripheral optical scattering on central visual performance, by assessing chromatic and achromatic contrast sensitivity (CS).
Methods :
In total, 19 participants were included in the study. Each participant performed three blocks of scattering conditions: control, 0.4 and 0.8 Bangerter foil, each with a clear central aperture of 8.0 mm. For each block, CS was tested monocularly at three different adaptation times (at 0 min, 30 min and 90 min) using a 2IFC-modified version of the Tuebingen CS test for 3 cpd and 12 cpd, while the fellow eye was covered. Chromatic stimuli were designed to match the cone type sensitivities of S-, M- and L-cones using the method of silent substitution. During CS testing, pupil size was controlled to ensure a smaller pupil size than the clear central zone of the Bangerter foils. CS changes were analyzed using linear mixed models.
Results :
The sensitivity of cone-types differed significantly from each other (all p<0.05), except the achromatic and L-cone type (p=0.87), where the S-cone type showed the minimum sensitivity across all testing conditions and M-cone CS exhibited the maximum, see Figure 1. Overall, CS was also influenced by the level of peripheral contrast reduction, while the 0.4 Bangerter foil showed a significant reduction compared to the control condition (p=0.04) and the 0.8 Bangerter foil condition (p=0.0008). Moreover, no central contrast adaptation to peripheral scattering was found, but reversely, a reduction of 0.11 log(CS) after 90 min and of 0.08 log(CS) between 30 min and 90 min (both p<0.0001).
Conclusions :
Central visual performance depends on the level of peripherally imposed scattering, which affects all cone types equally and non-selective. Adaptation to scattering was not found, but a decrease in CS over the time. Further research is required to determine whether peripheral contrast reduction leads to long-term retinal driven refractive changes.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.