| Abstract: | Objective: To determine the normative values of macular and optic nerve head parameters measured by optical coherence tomography (OCT) in healthy schoolchildren and to analyze the possible influence of individual factors on the main parameters of OCT. Methods: This cross-sectional study was part of a cohort study on refractive development in children and adolescents. Nine hundred thirteen students from the age of five to fifteen were recruited at three schools in Liling City, Hunan Province, and Yichang City, Hubei Province. Retinal thickness, retinal nerve fiber thickness (RNFL) and optic nerve head parameters were measured by OCT (DRI OCT Triton, Japan, Topcon). The normal value range was defined by P2.5-P97.5 or Mean±1.96 SD. Then the relationships between age, sex, refractive error, axial length and the main parameters were analyzed by a Spearman's correlation and multiple linear regression analysis. Results: The EDTRS for the foveal region, the normal values of retinal thickness and RNFL thickness in the central area were 193.72-262.68 μm and 0.67-8.18 μm, respectively. In the inner ring region, the retina was thickest in the superior quadrant (288.07-340.29 μm), followed by the nasal (283.89-340.53 μm) and inferior quadrants (283.85-337.21 μm), then the temporal quadrant (275.32-326.32 μm), while the RNFL was thickest in the inferior (24.40-33.01 μm) and superior quadrants (24.52-33.24 μm), followed by the nasal (20.89-28.35 μm) and temporal quadrants (20.54-24.45 μm). In the outer ring region, the retina was thickest in the nasal quadrant (266.97-323.27 μm), followed by the superior (254.81-305.03 μm) and inferior quadrants (241.54-292.42 μm), then the temporal quadrant (238.45-286.59 μm), while the RNFL was thickest in the nasal quadrant (42.38-63.03 μm), followed by the inferior (36.35-53.74 μm) and superior quadrants (36.19-53.64 μm), then the temporal quadrant (21.37-26.52 μm). In the optic disc, the retina was thickest in the superior (286.13-378.29 μm) and inferior quadrants (283.20-375.82 μm), followed by the temporal quadrant (256.90-325.30 μm), then the nasal quadrant (235.40-309.79 μm). The RNFL was thickest in the inferior quadrant (122.07-193.79 μm), followed by the superior (113.48- 188.28 μm), temporal (71.51-146.15 μm), and nasal quadrants (45.99-112.26 μm). The normative values of the disc area (DA), rim area (RA), cup volume (CV), C/D area ratio (CDAR), linear C/D ratio (LCDR) and vertical C/D ratio (VCDR) were 1.37-3.16 mm2 , 0.79-2.64 mm2 , 0.01-0.51 mm3 , 0.03- 0.64, 0.17-0.80 and 0.15-0.78, respectively. Multiple linear regression analysis showed that the spherical equivalent refractive error was correlated with the RNFL thickness of the macular central area, the nasal quadrant of the outer ring, the nasal quadrant of the optic disc, the inferior quadrant of the optic disc and DA, CV, VCDR (r=-0.197, -0.317, 4.458, 1.633, 0.069, 0.020, 0.040, all P<0.05). A significant negative correlation was found between age and the RNFL thickness of the macular central area, DA, CV, VCDR (r=-0.099, -0.020, -0.005, -0.007, all P<0.05), and a positive correlation was found between age and the RNFL thickness of the nasal quadrant of the outer ring (r=0.141, P=0.046). A positive correlation was found between the axial length and RNFL thickness of the macular central area and the nasal quadrant of the outer ring and CV, VCDR (r=0.414, 1.486, 0.022, 0.045, all P<0.001), and a negative correlation was found between the axial length and inferior quadrant of the optic disc (r=-2.192, P=0.012). Moreover, there was no correlation between gender and the other parameters, except for the RNFL thickness of the nasal quadrant of the outer ring (r=-1.066, P=0.002). Conclusions: This study provides the normative values of macular and optic nerve head parameters in healthy children. Meanwhile, we find that gender, age, refractive error and axial length all have a certain influence on the examination results of OCT. Thus, these factors should be taken into account when using OCT to evaluate and diagnose the fundus diseases of young children in clinical practice. |
