Structural Alterations in Choroid Noted During Menstrual Cycle

OCT has previously revealed cyclical variations in choroidal thickness and optic disc morphology during the menstrual cycle in reproductive-aged women, and in recent years, OCT-A has proven to be a valuable modality for evaluating intraocular blood flow and identifying microvascular alterations within the macula during the menstrual cycle. Taking it one step further, Turkish researchers recently used OCT-A to investigate how hormonal fluctuations during the menstrual cycle affect the microvasculature of the retina and choroid. They found structural alterations in the choroid, most notably in both peri­papillary thickness and choriocapillaris microvasculature in the inferior and temporal regions.  Estrogen surge may enhance microvascular perfusion, whereas hormon­ally suppressed states, such as oral contraceptives, may reduce it—highlighting the hormonal sensitivity of retinal and choroidal microcirculation. The researchers advised clinicians to be mindful of the influence of menstrual dynamics when evaluating OCT-A findings. Photo: Ozbek M, et al. BMC Ophthalmology. July 1, 2025. Click image to enlarge. A total of 31 healthy women with regular menstrual cycles were enrolled. Swept-source OCT-A imaging was performed during three standardized menstrual phases: early follicular (day 3), ovulatory (day 14) and mid-luteal (day 21). Macular and peripapillary regions were evaluated using 3x3mm and 4.5x4.5mm scan protocols, respectively. Vessel density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris was automatically quantified using the device’s software. Choroidal thickness was manually measured in all quadrants, and the foveal avascular zone (FAZ) area was manually delineated by two independent graders.In alignment with characteristics of the ovulation phase—i.e., elevated estro­gen and reduced progesterone levels—the peripapillary region exhibited a notable increase in VD measurements between menstrual cycle phases. This was particularly evident in the superior quadrant of the SCP, as well as in the inferior DCP and in the inferotempo­ral choriocapillaris, the authors noted. Post-hoc analysis revealed a pronounced increase in vessel density during the ovula­tory phase relative to both the follicular and mid-luteal phases.There was no statistically significant difference in SCP and DCP in the macular area, but a significant VD alteration was observed in the inferior quadrant of the choriocapillaris layer, possibly because the choroidal circulation exhibits a compara­tively limited capacity for autoregulation in comparison to the retina. “The choroid is more directly influenced by systemic conditions and exhibits reduced capacity to maintain constant blood flow during fluctuations in ocular perfusion pressure,” the authors explained in their article.These find­ings are consistent with recent studies that explor­ed hormonal influences on posterior ocular structures, including one reporting reduced deep capillary plexus vessel density in women using combined oral contraceptives—suggesting a hormone-mediated modulation of retinal microvas­culature detectable by OCT-A. Similarly, another study observed a significant decrease in choroidal vascular index values in individuals who used oral contraceptives, in compari­son to those who did not use them, suggesting there are alterations in the luminal component of the choroid.“These findings are complementary to our observation of increased VD during the ovulatory phase, suggesting that the physiological estrogen surge may enhance microvascular perfusion, whereas hormon­ally suppressed states such as (combined oral contraceptives) use may attenuate it, thereby highlighting the hormonal sensitivity of retinal and choroidal microcirculation,” the researchers suggested in their paper.To ensure optimal diagnostic accuracy and treatment planning, the authors recommend that clini­cians take the menstrual cycle phase into account when interpreting OCT-A data in women of reproductive age.Click here for the journal source. Ozbek M, Ozcaliskan S, Asri S, et al. OCTA-based assessment of macular and peripapillary vessel changes during the menstrual cycle. BMC Ophthalmology. July 1, 2025. [Epub ahead of print.]