Mood, pain and the menstrual cycle: potential confounding factors in automated perimetry?

Abstract

The main purpose of this study was to investigate the effect of the normal human menstrual cycle on the central visual field as measured with program 24-2 of the Humphrey Field Analyser. Subject groups comprised 18 normally menstruating women (F), and control groups of eight women taking oral contraceptives (P), and four men (M). Subjects attended 2–3 times weekly for 6-10 weeks and were unaware of the purpose of the study. Daily self-report questionnaires were used to aid the study's disguise and to assess mood and physical symptomatology. Overall, there was a large degree of inter- and intrasubject variability. Analysis of variance failed to identify repeatable fluctuations in visual field performance across menstrual cycle phase in P or F, or across a randomly allocated 28-day cycle in M. However, curve-fitting techniques identified a significant cosine curve in mean sensitivity of the visual field in group F over three cycles as a whole (P = 0.03), suggesting peaks of sensitivity around mid-cycle with low points paramenstrually. The extent of this fluctuation was 0–0.5 dB and therefore within normal limits and not clinically significant. Physical symptoms of abdominal pain and backache were greater paramenstrually in all women, with no repeatable cyclical pattern in symptoms of mood in either group of women. Overall, men reported higher scores of both mood swings and positive mood, and similar scores of irritability as women. Mean sensitivity and short-term fluctuation of the visual field were not found to be dependent upon mood and physical symptomatology, or with day of the week. In conclusion, it is unlikely that fluctuations in performance associated with the menstrual cycle, mood and physical symptoms are sufficient to confound interpretation of the results of automated perimetry.