Role of sex in retinal nerve fiber layer and macular thickness measurement by spectral domain optical coherence tomography

Purpose The aim of this study was to investigate the role of sex on retinal nerve fiber layer (RNFL) thickness and macular thickness measurement by spectral domain optical coherence tomography (SD-OCT). Patients and methods In this prospective observational study, 200 participants who fulfilled the inclusion and exclusion criteria were scanned three times as per predefined guidelines at 0, 30, and 60 min on the same day, by the same investigator using SD-OCT for measurement of RNFL and macular thickness. The observations were statistically analyzed and correlated. Results The RNFL thickness was greatest in the superior quadrant and thinnest in the temporal quadrant. The mean value of average RNFL thickness was 87.90±6.12 μm in females and 93.18±4.04 μm in males (range=74.33–99.67 μm). A statistically significant difference was found between males and females in all quadrants and in average RNFL thickness ( P <0.0005). The macular thickness was thinnest at the central zone (innermost 1-mm ring), thickest within the inner 3-mm ring, and diminished peripherally. The mean macular thickness was 272.95±8.40 μm in females and 289.42±12.32 μm in males. A statistically significant difference was found between males and females in all macular zones and in the mean macular thickness ( P <0.0005). Conclusion RNFL thickness and macular thickness were significantly thicker in males compared with females in healthy eyes. Sex should be used as an additional parameter in commercially available OCT machines, in addition to age, because of its potential in improving the existing RNFL thickness and macular thickness norms.