Purpose:
To evaluate circadian rhythm patterns in patients with advanced glaucoma and ocular normals using wrist actigraphy.
Methods:
Glaucoma patients, ages 50 to 90 years, with a cup-to-disc ratio ≥ 0.9 in both eyes and glaucoma stage of ≥ 3 in both eyes using the Glaucoma Staging System and normal age-matched controls with no co-morbid conditions nor medications affecting sleep were consecutively recruited. Patients were required to wear a watch sensitive to movement (i.e. wrist actigraphy) continuously for 14 days. A Hidden Markov Model was used to categorize frequency and duration of activity status into five states: sleeping, sleeping with movement, daytime napping, awake, and vigorous activity. A recurrent event survival analysis was used to model the time from waking each day to the onset of the first nap.
Results:
Fifteen advanced glaucoma patients and 14 normal controls (mean ages 74.3 and 67.2 years, respectively) successfully completed the study. The glaucoma cohort had a significantly higher percent of days with naps (50% vs. 15.9%, p=0.0017, t-test) and longer napping times (60.8 vs. 39.5 minutes, respectively, p=0.034, t-test) than normal controls. In addition, advanced glaucoma patients had a 47% greater chance of naping closer to their time of awakening than normal controls (95% confidence interval of hazard ratio: 1.13-1.92, p=0.0042, Figure). There was no significant difference in total sleeping time at night between glaucoma patients and normal controls (8.4 vs. 8.6 hours, respectively, p=0.72, t-test).
Conclusions:
Patients with advanced glaucoma nap at a higher frequency, longer duration, and earlier onset from their waking time than patients without glaucoma despite similar hours sleeping at night. Such differences in circadian rhythm patterns may be due to optic nerve pathology.
Keywords: circadian rhythms • clinical (human) or epidemiologic studies: prevalence/incidence • optic nerve