Abstract
Purpose: :
Sleep disturbances have been reported both in individuals with visual impairment as well as in individuals with pineal gland damage, however the relationship between aberrant photoreception and pineal gland dysfunction to sleep-wake cycle remains unclear. Stargardt’s disease (STGD) is an inherited macular degeneration due to excessive lipofuscin accumulation and retinitis pigmentosa (RP) is a genetically heterogeneous disorder that is characterized primarily by abnormal photoreceptor protein production. Retina specific gene mutations cause photoreceptor death, which leads to blindness. Some retinal genes, such as many of the RP genes, are expressed in the pineal gland and some are not, as in the case of STGD. If mutations cause death or dysfunction of photoreceptors, we hypothesize that they also cause pineal dysfunction, measurable by sleep disturbance. This study aims to compare the quality of sleep in patients with RP to those with STGD in order to explore whether sleep quality is affected unfavorably with gene expression in the pineal gland.
Methods: :
A total of 127 patients with STGD (N= 19; Mean age= 41.06; Range= 20-63) and RP (N= 108; Mean age =50.37; Range = 19-82) were interviewed by using the Epworth Sleepiness Scale and the Pittsburgh Sleep Quality Index (PSQI), a 19-question scale evaluating seven major components of sleep quality. Other possible explanations for sleep disturbances were assessed by using the Brief General Health Assessment Questionnaire (BGHA).
Results: :
Of the 127 interviewed patients, 8 RP and 3 STGD were excluded on the basis of their BGHA responses. On the remaining individuals, 53% of those with RP and 44% of those with STGD had a PSQI score of 5 or higher, indicating sleep disorder. The two groups differed only on one subscale, that of sleep disturbance, with the RP patients having more difficulties, t (38) = 2.665, p < .01.
Conclusions: :
The data collected to date in this study indicate that a significant proportion of people with inherited retinal dystrophies exhibit sleep disorders. Additional data are required to explore the possible links between specific gene expression (i.e., retina and/or pineal gland) and sleep disruption. Nonetheless, eye-care providers should consider exploring the question of sleep quality with their retinal-dystrophy patients
Keywords: retinal degenerations: hereditary • low vision • circadian rhythms