The Relationship of Photopic and Mesopic Contrast Sensitivity to Retinal-Choroidal Structural Characteristics in...

This study aimed to compare photopic and mesopic contrast sensitivity (CS) between low-to-moderate myopia (LMM) and high myopia (HM) groups, and to evaluate the associations between CS and chorioretinal structural and vascular parameters.

In this cross-sectional study, 108 participants were divided into an LMM group (n = 53, mean age = 21.0 years, mean SE = -4.25 diopters [D]) and an HM group (n = 55, mean age = 24.0 years, mean SE = -8.25 D). CS was tested under photopic (85 cd/m²) and mesopic (3 cd/m²) conditions. Chorioretinal parameters were measured using swept-source optical coherence tomography/optical coherence tomography angiography (SS-OCT/OCTA). Associations were assessed using univariate and stepwise multiple linear regression analyses.

The HM group exhibited significantly reduced CS under both photopic (1.07 ± 0.11 vs. 1.19 ± 0.09 in the LMM group, P < 0.001) and mesopic (median = 0.64 vs. 1.04 in the LMM group, P < 0.001) conditions. Compared to the LMM group, the HM group had a significantly thinner choroid and a higher choroidal vascularity index (CVI). Mesopic CS (CSm) demonstrated stronger and more extensive associations with chorioretinal parameters than photopic CS (CSp).

Chorioretinal alterations in high myopia appear to have a more profound impact on visual function under mesopic than photopic conditions. Given its sensitivity to both choroidal and retinal alterations, mesopic CS is a parameter that warrants further investigation for its potential in assessing functional impairment in myopia.

Measuring mesopic contrast sensitivity offers a superior functional indicator of underlying chorioretinal health in myopia, allowing for earlier and more comprehensive assessment of visual decline in clinical practice.