Optical amplification effect of optical coherence tomography on measurement of macular retinal thickness of children and adolescents with mild-to-moderate myopia

AIM:To evaluate the effect of optical amplification on macular retinal thickness measurements in myopic eyes of children and adolescents using optical coherence tomography(OCT).METHODS:A total of 68 cases(126 eyes)of children and adolescents aged 6 to 18 years old attending our optometric center from April 2023 to January 2024 were selected. They were divided into 44 cases(83 eyes)in the mild myopia group(-0.50 D<SE≤-3.00 D)and 24 cases(43 eyes)in the moderate myopia group(-3.00 D<SE≤-6.00 D)according to the spherical equivalent(SE). The macular retinal thickness was measured using OCT, and the measurements were corrected for optical amplification to compare the differences in macular retinal thickness before and after correction, and to analyze the relationship between the macular retinal thickness and axial length(AL)and the SE before and after correction.RESULTS:In the mild myopia group, there was no statistically significant difference between the retinal thickness in each quadrant of the macular area before and after correction and the mean retinal thickness(all P>0.05). In the moderate myopia group, the differences between the retinal thickness in each quadrant of the macula and the mean retinal thickness before and after correction were statistically significant(all P<0.001). Before correction, there was a significant difference in retinal thickness on the temporal side of the outer ring and above the outer ring of the macula in both groups(P=0.019, 0.035). However, retinal thickness in the other quadrants was not statistically different between the two groups(all P>0.05). There were significant differences between the two groups in the macular fovea, the nasal side of the inner ring, the temporal side of the inner ring, the upper inner ring, the lower inner ring, the nasal side of the outer ring, and the mean retinal thickness after correction(all P<0.05). Before correction for optical amplification, retinal thickness of the outer ring of the macula was positively correlated with SE(all P<0.05)and negatively correlated with AL(all P<0.05). By correction, a significant negative correlation was found between the macular fovea, the inner ring, and the mean retinal thickness with SE(all P<0.05). In addition, retinal thickness in all quadrants of the macula was positively correlated with AL(all P<0.001).CONCLUSION:The optical amplification affects the accuracy of retinal thickness measurements in the macular region of myopic eyes of children and adolescents, and the effect becomes more significant as the AL increases.