To investigate the correlation of macular retinal thickness and refractive error using spectral-domain optical coherence tomography (SD-OCT).

A total of 120 eyes with no posterior abnormalities were enrolled in the present study. Subjects were divided into 3 groups based on their spherical equivalent. Visual acuity, refraction, slit lamp examination, tonometry and fundus examination were performed. Retinal thickness between the RPE and IS/OS junction was measured at the fovea, 1 mm (inner ring) and 2 mm (outer ring) superiorly, inferiorly, nasally and temporally using SD-OCT. Overall average thickness, average foveal thickness, and the inner and outer ring macular thickness were measured.

The average foveal thickness was significantly greater in the high myopic eyes than in the low to moderate myopic and emmetropic eyes ( p = 0.001). However, the RPE-IS/OS junction thickness of the foveola and the outer macular thickness were significantly lower ( p = 0.001, p = 0.002) in the high myopic eyes. There was a weak, but significant negative correlation between refractive error and average foveal thickness (r = -0.38, p = 0.001). A positive correlation was found between refractive error and the RPE-IS/OS junction thickness (r = 0.40, p = 0.001).

Macular retinal thickness is related to refractive error in normal subjects. Effects of eyeball elongation are more apparent in high myopic eyes than in low to moderate myopic eyes. A significant decline in the RPE-IS/OS junction thickness suggests the photoreceptor outer segments in the foveola are damaged in high myopic eyes.