Sleep Patterns Linked to Macular Disease

Diana Phillips

February 22, 2016

Too much sleep may be tied to retinal problems, a new study suggests.

Adult patients of a retina practice with a diagnosis of geographic atrophy secondary to age-related macular degeneration (AMD) were significantly more likely than those without the condition to report sleeping more than 8 hours per night. Further, patients who reported sleeping more than 8 hours per night had a sevenfold increased risk for geographic atrophy secondary to AMD, Rahul N. Khurana, MD, from Northern California Retina Vitreous Associates, Mountain View, California, and colleagues report in an article published in the February issue of Retina.

"It is important to emphasize that association does not imply causation, as longer sleeping times will not directly cause atrophy," the authors stress.

Previous studies have demonstrated a relationship between duration of sleep and cardiovascular disease and hypertension, both of which have been associated with AMD. In this clinic-based, cross-sectional study, the researchers explored the relationship between sleep patterns and advanced AMD in 1003 consecutive patients in a community retina practice who were surveyed about sleep histories with a standardized questionnaire.

Of the patients included in the study, 500 (mean age, 63 years) did not have AMD, 126 (mean age, 78 years) were diagnosed with early AMD, 316 (mean age, 83 years) had neovascular AMD, and 61 (mean age, 84 years) had evidence of geographic atrophy secondary to AMD.

The mean sleep duration for patients without AMD was 7.97 hours, compared with 8.17 hours, 9.00 hours, and 7.97 hours, respectively, for those with early AMD, neovascular AMD, and geographic atrophy, the authors report. The proportion of patients who reported getting more than 9 hours of sleep nightly was 25%, 28%, 41%, and 51%, respectively, for patients without AMD, with early AMD, with neovascular AMD, and with geographic atrophy.

In a multivariate analysis adjusted for age, sex, and smoking history, sleep hours were significantly associated with geographic atrophy, the authors write, noting that the age-adjusted odds ratio for sleeping more than 8 hours per night was 7.09 for patients with geographic atrophy compared with those without AMD.

The researchers suggest possible explanations for the link between longer sleep durations and geographic atrophy, including higher rates of depression in patients with AMD. In particular, poor vision is associated with depression in AMD, and depression is associated with altered sleep patterns, they explain.

"Another explanation is that a recent study showed worse cognitive function and higher levels of cognitive impairment with geographic atrophy independent of visual acuity," they write. "The comorbidity of cognitive impairment and geographic atrophy limits the quality of life and exacerbates the disability of this population, which may be related to the altered sleep times observed in this study."

Finally, because patients with AMD had visual impairment, particularly in dim lighting, "they may go to sleep earlier in the evening," the authors hypothesize.

Although causation cannot be implied from the findings, "[t]he altered sleep patterns illustrate another morbidity that patients with AMD suffer from and merit further investigation," the authors conclude.

The authors have disclosed no relevant financial relationships.

Retina. 2016;36:255-258. Abstract


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