Purpose: To investigate the variation of macular light sensitivity (MLS) in myopic Chinese adults by using microperimetry.
Methods: MLS was recorded with the MP1 microperimeter (Nidek Technologies, Padova, Italy) in eyes affected by various degrees of myopia. Subjects were divided into group A (18-30 years) and group B (31-60 years). Subjects in both age groups were further divided based on refractive status: (1) high myopia (spherical equivalent, SE<-6.00 D); (2) low to moderate myopia (-6.00 D<or=SE<or=-1.00 D); and (3) no myopia (-1.00 D<SE<or=+0.50). All patients had corrected visual acuity greater than 20/20. The macular area covered by the MP1 grid contains nine areas. MLS was quantified in each part and correlated with the refractive data.
Results: MLS correlated significantly with SE or axial length (AL). Average MLS of the outer ring, total macula, and superior quadrant significantly decreased in the high and the low to moderate myopia eyes (both P<0.05) in both age groups. MLS in the temporal, inferior, and nasal quadrants decreased in the high myopia eyes, but not in the low to moderate myopia eyes, except in the temporal quadrant in group A and in the nasal quadrant in group B.
Conclusions: Axial myopia was associated with reduced total and quadrant-specific MLS, particularly in the superior quadrant. These findings emphasize functional differences in the macula between high, low to moderate, and no myopia. Any evaluation of MLS by MP1 microperimetry in the macula should be interpreted in the context of the degree of refractive error and the region of measurement.