Evidence of a possible impact of the menstrual cycle on the reproducibility of scotopic ERGs in women

The purpose of this study was to investigate the impact of gender and menstrual cycle on the electroretinogram (ERG). Photopic and scotopic ERGs were obtained in 14 females during the luteal and follicular phases of their menstrual cycle and compared to those obtained on two separate (7 days or 14 days apart) sessions from seven age-matched control male subjects. Our results confirm that the amplitude of the photopic ERGs of females is significantly (P < 0.05) larger than males, and this, irrespective of the cycle phase. In comparison, scotopic ERGs revealed significant male-female differences only during the follicular phase. While in males, no significant (P > 0.05) intersession (7 day or 14 day intervals) variability could be demonstrated, significant (P < 0.001) intersession (luteal-follicular) variability was observed in the scotopic ERGs of our female participants, with 8 of the 14 women, demonstrating a marked increase of 20.17 +/- 4.8% in the follicular ERG compared to the luteal. Our data suggests there should be separate normal ERG values for men and women and that the phase of the menstrual cycle should be taken into consideration when interpreting the ERG results from women.