Assessing the contrast sensitivity function in myopic parafovea: A quick contrast sensitivity functions study

PurposeCompare peripheral contrast sensitivity functions (CSF) between myopes and emmetropes to reveal potential myogenic risks during emmetropization. Materials and methodsThis observational, cross-sectional, non-consecutive case study included data from 19 myopes (23.42 +/- 4.03 years old) and 12 emmetropes (22.93 +/- 2.91 years old) who underwent central and peripheral quick CSF (qCSF) measurements. Summary CSF metrics including the cut-off spatial frequency (cut-off SF), area under log CSF (AULCSF), low-, intermediate-, and high-spatial-frequency AULCSFs (l-, i-, and h-SF AULCSFs), and log CS at 19 SFs in the fovea and 15 peripheral locations (superior, inferior, temporal, and nasal quadrants at 6, 12, 18, and 24 degrees eccentricities, excluding the physiological scotoma at 18 degrees) were analyzed with 3-way and 4-way between-subjects analysis of variance (ANOVA) (alpha = 0.05). ResultsThree-way ANOVA showed that myopes had significantly increased AULCSF at 6 degrees (mean difference, 0.08; 95% CI, 0.02-0.13; P = 0.007) and 12 degrees (mean difference, 0.09; 95% CI, 0.03-0.14; P = 0.003). Log CS at all 19 SFs were higher in the myopia group compared to the normal group (mean differencesuperior, 0.02; 95% CI, 0.01-0.20; P = 0.02 and mean differenceinferior, 0.11; 95% CI, 0.02-0.21; P = 0.01) at 12 degrees. The h-SF AULCSF at 6 degrees (mean differenceinferior, 1.27; 95% CI, 0.32-2.22; P = 0.009) and i-SF AULCSF at 12 degrees (mean differencesuperior, 5.31; 95% CI, 4.35-6.27; P < 0.001; mean differenceinferior, 1.14; 95% CI, 0.19-2.10; P = 0.02) were higher in myopia vs. normal group. ConclusionWe found myopia increased contrast sensitivity in superior and inferior visual field locations at 6 degrees parafoveal and 12 degrees perifoveal regions of the retina. The observation of increased contrast sensitivities within the macula visual field in myopia might provide important insights for myopia control during emmetropization.