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Abstract

The primary purpose of this thesis was to investigate the effect of the normal human menstrual cycle on visual performance.

Optimum experimental design was established for the serial measurement of the peripheral visual field by automated perimetry using program 30/60-2 of the Humphrey Field Analyser (HFA). A proportion of subjects demonstrated learning effects over the first two sessions. In subsequent investigations the first two field plots were discarded from the data set.

A pilot study investigated the effect of the menstrual cycle on central 30-2 and peripheral 30/60-2 fields of the HFA on 11 normally menstruating women. Subjects attended two to three times weekly for 10 weeks. There was much inter- and intra-subject variability. Although mean sensitivity of the visual field decreased over the first cycle, this was not repeated in a second cycle. The large degree of variability and noise inherent in the data may be masking any menstrual cycle fluctuation. Self-reported symptomatology was assessed using the Moos Menstrual Distress Questionnaire (MDQ). Subjects prospectively reported few fluctuations in symptomatology associated with the menstrual cycle.

The main study, using a protocol design taking into account conclusions drawn from the pilot study, investigated the effect of the menstrual cycle on the central 24-2 field of the HFA, contrast sensitivity at five spatial frequencies (0.75, 1.5, 4, 8 and 14cpd), logMAR high and low contrast visual acuity, and pupil diameter. Subject groups comprised 18 normally menstruating women (F), and control groups of eight women taking oral contraceptives (P) and four men (M). Subjects attended two to three times weekly for six to 10 weeks and were unaware of the purpose of the study. Daily self-report questionnaires assessed mood and physical symptomatology. There was a large degree of inter- and intra-subject variability with overall no significant repeatable fluctuation in any visual field performance measure across the menstrual cycle in P or F, or across a randomly allocated 28 day cycle in M. Curve-fitting techniques identified a significant cosine curve in mean sensitivity of the visual field in group F over the three cycles as a whole (F(l,245)=4.62, p=0.03), suggesting peaks in sensitivity around mid-cycle with low points paramenstrually. However, when repeated on individual cycles, a significant cosine curve was identified in one cycle alone, thus highlighting inter-cycle differences. The extent of fluctuation was 0.5dB and thus not clinically significant. These significant curve fits in the F accounted for less than 10% of the variance in mean sensitivity, with a spurious curve in one 'cycle' of the M control group accounting for about 50% of the variance. Any conclusions must therefore be drawn cautiously.

Publication Type:	Thesis (Doctoral)
Subjects:	R Medicine > RZ Other systems of medicine
Departments:	School of Health & Psychological Sciences > Optometry & Visual Sciences School of Health & Psychological Sciences > School of Health & Psychological Sciences Doctoral Theses Doctoral Theses

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