Sleep disorders: a risk factor for normal-tension glaucoma?

To determine the prevalence of sleep-related symptoms and sleep-related breathing disorders by polysomnography in patients with normal-tension glaucoma (NTG).

This comparative case series included 23 patients with NTG, 14 NTG suspects, and 30 comparison patients without NTG. A sleep history was obtained and determined to be positive or negative. Polysomnography was offered for patients with a positive sleep history. Prevalence of a positive sleep history and prevalence of sleep disorders were the main outcome measures.

The NTG, NTG suspect, and comparison groups did not differ with respect to age, body mass index, systemic disease, gender, or race. Thirteen (57%) of 23 patients with NTG, 6 (43%) of 14 NTG suspects, and 1 (3%) of 30 comparison patients had a positive sleep history (P = 0.001). Nine of 13 patients with NTG and four of six NTG suspects with a positive sleep history chose to undergo polysomnography. Seven (78%) of nine patients with NTG and all four NTG suspects undergoing polysomnography were diagnosed with a sleep disorder. Five patients with NTG had sleep apnea and two had sleep hypopnea. Two NTG suspects had sleep apnea; one had sleep hypopnea; and one had upper airway resistance syndrome. The one comparison patient with a positive sleep history had upper airway resistance syndrome by polysomnography.

Sleep-disturbed breathing may be a risk factor for NTG. Although we do not provide evidence for a cause-and-effect relationship, various physiologic factors produced by sleep-disturbed breathing may play a significant role in the pathogenesis of this optic neuropathy. We recommend obtaining a sleep history from patients with NTG and performing polysomnography in those patients with sleep disturbance symptoms.