Sleep Quality in Age-Related Macular Degeneration (AMD)

Abstract

Purpose: To assess the effect of AMD on sleep quality. Photosensitive retinal ganglion cells (pRGCs) relay the light signal to entrain the body’s circadian clock. The effect of AMD on pRGCs, and the non-visual responses to light that pRGCs mediate, is unknown.

Methods: Patients attending medical retina clinics with AMD and no other significant ocular comorbidity completed the Pittsburgh Sleep Quality Index (PSQI). A global PSQI score (0-21) is calculated from seven components: sleep quality; latency; duration; habitual sleep efficiency; sleep disturbance; use of sleep medication; and daytime dysfunction. A global score of >5 reflects disturbed sleep. PSQI scores were assessed in relation to best visual acuity (VA) across both eyes and stage of AMD (early vs late).

Results: 81 patients participated in this study (four patients were excluded due to existence of ocular comorbidities). Thus data from 77 eligible patients were analysed with a mean age of 78 years. Mean global PSQI was 5 (range 1-14) and 31 patients (40%) had a score suggestive of a sleep problem (i.e. PSQI >5), though this did not correlate with logMAR visual acuity in AMD patients (r = -0.005). There was no significant difference in global PSQI between groups of patients according to stage of AMD (p = 0.222).

Conclusions: No relationship was found between global PSQI score and best VA across both eyes, or disease stage, in our study population of AMD patients. This implies that sleep is not affected by age-related macular degeneration. Although 31 patients (40%) had a global PSQI of >5 and mean global PSQI across the group was 5, suggesting prevalent sleep disturbance, this cannot be attributed to AMD. Indeed, sleep disturbance in healthy older people has been previously reported. pRGCs are distributed in a reticular fashion over the entire retina and receive input from rods and cones. Thus, compensatory mechanisms due to rod and cone survival, as well as peripheral pRGC survival, may allow a normal sleep phenotype to persist despite AMD. Our data support the idea that central retinal degeneration is unlikely to affect sleep and circadian entrainment.

Keywords: 458 circadian rhythms • 412 age-related macular degeneration • 648 photoreceptors