Various, and conflicting, findings have been reported about complex ocular changes that can occur during women’s menstrual cycle, as the eye is believed to also respond to sex hormones. In a recent study, researchers evaluated the effects of the menstrual cycle on the retinal vascular status of healthy women with regular natural menstrual cycle of 28 to 30 days.

A total of 62 right eyes of 62 women were included. The women’s retinal vascular status was measured by OCT angiography at three time points: the early follicular, ovulatory and midluteal phases of the menstrual cycle. The main outcome measures were foveal avascular zone parameters, and perfusion density in the superficial retinal capillary plexus as well as in the deep retinal capillary plexus. The mean arterial pressure, spherical equivalent best-corrected visual acuity, intraocular pressure and axial were also measured.

The study showed perfusion in the deep retinal capillary plexus decreased in the nasal and inferior ETDRS subfields during the ovulatory phase, while the superficial capillary plexus was unchanged.

Previous research suggested that the deep capillary plexus might be the primary site of venous outflow for the entire retinal microvasculature, leading the researchers of this current study to believe that “the physiologic differences in structure and function between the [superficial] and [deep plexuses] might cause them to be affected differently in the menstrual cycle.”

“As the menstrual cycle spans a relatively long period of time in women and the hormones cyclically fluctuate, we tend to consider these findings as normal physiologic fluctuations without adverse effects on ocular function,” the authors concluded in their study. “Therefore, the menstrual phase must be taken into consideration if any significant changes are detected in the partial subfields of the deep capillary plexus by OCT-A in women, especially in the nasal and inferior ETDRS subfields.”

Guo L, Zhu C, W Ziqi, et al. Retinal vascular changes during the menstrual cycle detected with optical coherence tomography angiography. Journal of Ophthalmology. Epub ahead of print.