Morphological Assessment of the Retina and Optic Nerve Head in Healthy Individuals in Erzurum via Optical Coherence Tomography

Purpose: To assess the effects of age and sex on ocular optical biometric parameters, including the retinal nerve fiber layer (RNFL), optic nerve hypoplasia (ONH), retinal thickness, and ganglion cell complex (GCC), in healthy individuals via spectral-domain optical coherence tomography (SD-OCT) with a Spectralis device (Optovue, Inc., Fremont, CA). Methods: Structural measurements of the retina and posterior segment were obtained from healthy participants at the Ophthalmology Department of Erzurum City Hospital. This anatomical study incorporated measurements from both eyes of each individual for analysis. OCT was employed to assess macular thickness and retinal layer parameters via both macular map and line scan protocols. The conformity of the numerical data to a normal distribution was assessed via the Mann–Whitney U test, with the significance level set at 0.05 for all the statistical analyses. Results: The study population consisted of 165 healthy individuals ranging in age from 18--80 years. Among the 165 participants, 54 (33%) were male. In terms of age distribution, 67 individuals (41%) were aged 18–30 years, 57 (34%) were between 31–40 years, 23 (14%) were in the 41–50 years, 10 (6%) were aged 51–60 years, and 8 (5%) were between 61–80 years. Age-related thinning in the RNFL was observed in both eyes, but the changes were not statistically significant ( p >0.05). ONH parameters showed significant age-related changes. The cup-to-disc area and volume ratios increased, whereas the rim area decreased significantly ( p <0.05). The disc area remained stable. The periosteal thickness and volume significantly decreased with age in both eyes ( p <0.05), whereas the central macular thickness did not significantly change. Parafoveal thinning was significant only in the left eye ( p =0.033). Inferior GCC thickness decreased significantly in individuals over 50 years of age ( p <0.05). FLV and GLV increased with age, suggesting early structural alterations. Conclusions: This study provides evidence that the process of aging is associated with structural changes in the optic nerve head and retinal layers. Notable age-related increases in the cup-to-disc ratios and decreases in the rim area are indicative of alterations to the optic nerve. Significant thinning in the perifoveal and inferior GCC regions, particularly in individuals over 50 years of age, suggests early neurodegenerative changes. Increased focal loss volume (FLV) and global loss volume (GLV) values may be indicative of subclinical retinal damage, highlighting the necessity of accounting for age when interpreting OCT parameters.