Purpose: To identify sex-related differences and age-related changes in individual retinal layer thicknesses in a population of healthy eyes across the lifespan, using spectral domain optical coherence tomography (SD-OCT).
Methods: In seven institutes in Japan, mean thicknesses of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor inner segment (IS), and photoreceptor outer segment (OS) were measured using SD-OCT with a new automated segmentation protocol in 256 healthy subjects.
Results: Interoperator coefficients of variability for measurements of each layer ranged from 0.012 to 0.038. The RNFL, GCL, IPL, and INL were thinnest in the foveal area, whereas the OPL+ONL and OS were thickest in this area. Mean thicknesses of the INL and the OPL+ONL were significantly greater in men (P = 0.002 and 0.001, respectively). However, mean RNFL thickness was greater in women (P = 0.006). Thicknesses of the RNFL, GCL, IPL, INL, and IS correlated negatively with age. Thickness of the OPL+ONL was not correlated with age, and thickness of the OS correlated positively with age. Inner retinal (RNFL+GCL+IPL) thickness over the whole macula correlated negatively with age (P < 0.001), but outer retinal (OPL+ONL+IS+OS) thickness did not. Thicknesses of layers did not correlate with axial length.
Conclusions: Macular layer thicknesses measured on SD-OCT images in healthy eyes showed significant variations by sex and age. These findings should inform macular layer thickness analyses in SD-OCT studies of retinal diseases and glaucoma.