The purpose of this study was to investigate the two-dimensional peripheral refraction in fellow eyes of patients with isomyopia and anisomyopia.
Sixty-eight young adults were recruited, including 25 isomyopes with interocular differences (IODs) of foveal refraction 1.50 D. Peripheral refraction across an area of the visual field of 60° × 36° with a resolution of 1° was measured using a custom-made Hartmann-Shack wavefront sensor. The retinal area was divided into 3 × 3 zones for comparison between the fellow eyes.
There was no difference of refraction in all corresponding zones between the fellow eyes in the isomyopic group (all P > 0.05). The IODs between more myopic (MM) eyes and less myopic (LM) eyes in the anisomyopic group ranged from -1.40 to approximately -2.46 D (all P <0.001), which was flagged in the center and attenuated in peripheral zones by varied magnitudes. In the stratification analysis for different levels of anisomyopia, the nasal retina first presented significant relative hyperopic shifts compared to the center, followed by the temporal retina. In contrast, the superior and inferior periphery only differed from the center when the central IOD was greater than 3.00 D.
The two-dimensional peripheral refraction patterns showed a mirror symmetry between the fellow eyes of a patient with isomyopia. However, in the anisomyopic group, peripheral refraction showed significantly relative hyperopic shift when compared with the center and developed with a varied rate in different areas. These findings may indicate an asymmetrical variation in the peripheral refraction patterns during myopia progression.