The relationships between mesopic light sensitivity and macular inner and outer retinal layer thicknesses in older healthy adults

Abstract

AbstractPurpose: Structural and functional markers are important for the early detection of neurodegenerative diseases of the eye. This study investigates the relationships between macular layer thicknesses and mesopic light sensitivity (MLS) in older healthy eyes.Methods: Measurements were made in 38 eyes of 38 healthy individuals of mean age 67 ± 5.6 years (range 60–80 years) and good visual acuity. MLS was measured with macular integrity assessment (MAIA) microperimetry at the central 10° diameter circle. MLSs at the central subfield (1° radius) and at four regions (temporal, nasal, superior, inferior) of the parafoveal ring (3°–5° radius of eccentricity) were registered. Total, inner, and outer retinal layer (IRL and ORL) thicknesses were measured in the macular region through spectral‐domain optical coherence tomography (SD‐OCT). Relationships between MLS and the retinal thickness in the corresponding macular region were examined using forward stepwise multiple linear regression analyses.Results: ORL and IRL thickness in the inferior parafoveal ring were significant contributing factors to the inferior MLS (ORL: p < 0.0001; IRL: p = 0.0003; R2 model = 51%). Increased ORL thickness and decreased IRL thickness correlated with worse MLS. The total retinal thickness, age, sex, refractive error, axial length, retinal illuminance or visual acuity variables were not found to be significant predictors of MLS.Conclusions: ORL and IRL thicknesses predict inferior parafoveal MLS in healthy older eyes. The measurement of MLS in combination with macular layer thicknesses may be useful for detecting loss of sensitivity caused by early degenerative diseases of the retina.