The effect of physiological changes in estradiol hormone during the follicular phase of the menstrual cycle in healthy women on retinal ganglion cell function, retinal and optic nerve vascularization and structure

PURPOSE: This study aimed to investigate the effects of estradiol changes occurring during the early follicular phase of the menstrual cycle on retinal ganglion cell function, retinal and optic nerve vascularity and structure in healthy adults using pattern electroretinography (PERG), optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA). METHODS: The study included 26 healthy subjects with a visual acuity of 1.0. Serum hormone levels, intraocular pressure (IOP), cycloplegic spherical equivalent (SE), PERG, retinal nerve fiber layer (RNFL) thickness and OCTA measurements were evaluated. PERG tests were performed using the Metrovision Monpack system. Spectral-domain OCT (Topcon Corporation, Tokyo, Japan); OCTA (Optovue, Inc, Fremont, CA) devices were used. All tests were conducted on the 1st and 14th days of the menstrual cycle, and the results were compared. RESULTS: The mean serum estradiol values on days 1 and 14 were 51 ± 19 ng/L and 304 ± 50 ng/L, respectively. PERG revealed no statistically significant differences in the amplitude or latency of the P50 and N95 waves between days 1 and 14. RNFL thickness did not differ significantly in the mean, superior, or inferior quadrants (p = 0.90, p = 0.85, and p = 0.39, respectively). OCTA analysis showed that peripapillary and macular vascular density values were similar between days 1 and 14 (p > 0.05). Correlation analysis revealed no significant relationship between electrophysiological parameters, RNFL thickness measurements, and retinal vascular densities (p > 0.05). CONCLUSION: In healthy women, no significant functional, vascular, or structural differences were observed in PERG, OCT, or OCTA parameters between low and high estradiol levels on days 1 and 14 of the menstrual cycle. Unlike the persistently low estradiol levels seen in menopause, physiological estradiol fluctuations during a healthy menstrual cycle do not cause functional, structural, or vascular changes in the optic nerve or retina.