Abstract
Purpose :
Myopia progression might alter the morphology of the posterior eye, particularly the neural retina and the choroid. In this work we investigated whether, and eventually to what extent, the amplitude of myopia correlates with both retinal and choroidal thickness measured with a commercial swept-source optical coherence tomography (OCT) instrument.
Methods :
Retinal OCT images from 42 myopes (25 females and 17 males; mean age: 27.1±4.0 years) were acquired around the fovea. Subjects were distributed into three groups according to their objective refraction: low myopia (>-1D), moderate myopia (-1D to -4,5D] and high myopia [-4,5D to -12D]. The OCT images were digitally processed, correcting geometrical distortions and curvature, with a custom MATLABTM software adopting the Bruch membrane as the reference plane for intra-retinal distances. From the so-processed images, retinal and choroidal thicknesses were semi-manually obtained at four different eccentricities along the horizonal meridian (fovea, 2.25mm nasal; 2.25 and 3.38mm temporal from fovea) using ImageJTM. Three measurements were obtained from each location.
Results :
Thicknesses of both retina and choroid followed a normal distribution (Shapiro-Wilk test). Foveal retinal thickness did not correlate with refraction in any group. On the opposite, certain linear correlation (R=0.45) appeared for sub-foveal choroidal thickness. When the groups were considered, the mean sub-foveal choroidal thickness was statistically different in the high myopia group (ANOVA test). Nasal and temporal retinal thickness exhibited a moderate association with refraction, with significant differences between low-moderate myopia and high myopia groups. Neither nasal nor temporal at 3.38 mm choroidal thickness correlated with ocular refraction. Nevertheless, significant differences between low and high myopia groups were found at 2.25-mm temporal location.
Conclusions :
A significant decrease in sub-foveal choroidal thickness was found in the high myopia group with no variations in foveal thickness between groups. Retinal thickness correlated with refraction at 2.25mm eccentricity, nasal and temporal locations, with high myopes exhibiting lowest values. Retinal and choroidal thicknesses show differences as a function of refraction and eccentricity, which might be a marker for myopia evolution, also serving to evaluate current treatments.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.