Decreased sleep quality in patients suffering from retinitis pigmentosa

The purpose of this study was to assess the prevalence of sleep disturbance in subjects diagnosed with retinitis pigmentosa (RP), as well as the influence of age and gender. Sleep quality was assessed, by means of the Pittsburgh Sleep Quality Index (PSQI), in people with RP (n=177) and gender-and age-matched normally sighted individuals (n=491). The population was divided, according to their age, in eight decade groups. People on shift-work, with affective disorders or with visual impairment other than RP, were excluded. The influence of cataracts in sleep quality was also studied in non-RP people (n=57), with cataracts significantly impairing visual acuity. Another group of healthy controls (n=190) was studied in different seasons of the year for a possible seasonality in sleep disturbance. Global sleep quality decreased in an age-dependent manner in RP-patients, especially from the second decade of life. Retinitis pigmentosa-patients showed, in relation to age-matched controls: lower subjective sleep quality and efficiency, longer sleep latency, shorter sleep duration, higher daytime dysfunction and a higher use of sleeping medication. No significant differences in sleep quality were found among RP-patients or controls depending either on their gender or on the presence of cataracts. Normal sighted individuals did not show seasonality in their sleep quality. We conclude that the sleep quality of RP-patients decreases in an age-dependent manner and points to the probably degeneration of photoreceptors mediating the photic input to the suprachiasmatic nuclei of the hypothalamus in this disease.