Use of Spectral-Domain Optical Coherence Tomography to Analyze Macular Thickness According to Refractive Error

ABSTRACT

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