We measured the relationship between the occurrence of photopsias (spontaneous phosphenes), and retinitis pigmentosa (RP) subjects' level of vision, light exposure, and psychosocial factors to attempt to confirm RP patients' previous reports of these associations.
A total of 36 RP subjects self-administered PC-based binocular visual acuity, contrast sensitivity, and visual field tests at home twice a week, for 16 sessions in 2–3 months. After each session, subjects reported photopsias during the vision tests and completed questionnaires: Epworth Sleepiness Scale, Stanford Sleepiness Scale, Perceived Stress Scale, and Positive and Negative Affect Schedules.
Across all subjects, photopsias occurred during 47% of sessions. Five (14%) subjects never noted photopsias, while five others noted photopsias at every session. Two-thirds of subjects experienced photopsias frequently (>20% of sessions). On average, the odds of noticing photopsias increased by 57% for every 1-point increase in mean perceived stress (OR=1.57; 95% CI: 1.04, 2.4; P=0.03) or reduced by 38% for every 1-point increase in positive mood (OR=0.62; 95% CI: 0.39, 0.98; P=0.04), after adjusting for age, gender, and vision. Similarly, the odds of experiencing photopsias during a session increased by 16% for every 3-point increase in perceived stress and decreased by 17% for every 3-point increase in positive mood, after adjusting for age and gender (OR=1.16; 95% CI: 1.01, 1.33; P=0.048)(OR=0.83; 95% CI: 0.73, 0.94; P=0.004), respectively. Frequency of photopsias was not statistically significantly related to other factors measured.
Increased photopsias appear to be related to times when subjects report increased perceived stress and/or decreased positive mood, rather than RP patients' age, level of vision, reported light exposure, or sleepiness.