Retinal nerve cells damaged by glaucoma may affect the sleep quality of patients, according to findings from new research published this week (6 April).The researchers believe that their work adds to the body evidence which shows glaucoma is linked with disrupted regulation of the circadian rhythm and increased sleep disturbance.
In a small study of 45 patients, 32 of whom had glaucoma, researchers at the University of São Paulo in Brazil looked at the effect of damage to retinal nerve cells on sleep quality in patients with the common eye disease.
The trials focused on intrinsically photosensitive retinal ganglion cells (ipRGCs), which regulate functions such as pupil dilation and play a role in synchronising circadian rhythm.
Cell function was measured by stimulating the cells with flashes of either blue (470nm) or red (640nm) light for a second, at about a tenth the brightness of a candle, and the pupil’s response measured. A number of measurements were also taken as the subjects slept under controlled conditions, including monitoring of rapid eye movement and arousal from sleep.
Glaucoma patients were found to have fewer hours of sleep on average. They also showed reduced pupilary reflex to the light flashes. OCT scans also revealed significantly reduced thickness of the retinal nerve fibre layer (RNFL) in glaucoma patients.
The authors write that their data support that glaucoma leads to RGC death and that the loss of ipRGC function could lead to sleep disturbances. They add: “Concerns about sleep disturbances in patients with glaucoma should be incorporated into clinical evaluations.”
The research is published in the journal Ophthalmology.