Glaucoma and the connection between sleep apnea

Are sleep apnea and glaucoma connected? While no conclusive answer can be found among the many studies that have focused on the crossover of these two conditions, many medical experts believe that sleep apnea patients face an increased risk of glaucoma.

For starters, the Mayo Clinic lists glaucoma among the eye problems that research has connected to obstructive sleep apnea (OSA).¹ The New York Times Health Guide agrees: “People with certain medical or physical conditions, including diabetes, migraine, nearsightedness, and sleep apnea, appear to have a higher risk for glaucoma.”²

So sleep apnea and glaucoma do seem to be connected — but the nature of why is largely unknown. Much of that uncertainty stems from the fact that, aside from the obvious cause of damage to the eye, the exact cause of glaucoma “remains unknown,” according to the Mayo Clinic’s guide to glaucoma.³

“For reasons that doctors don’t fully understand, increased pressure within the eye… is usually, but not always, associated with the optic nerve damage that characterizes glaucoma,” the guide states.

So, when faced with a health condition with unknown causes, it’s not unusual for researchers to examine any possible lead. And, to that effect, the overlap between sleep apnea and glaucoma has been well documented over the years.

In 2000, the journal Ophthalmologica published a study concluding that “sleep-associated diseases, like sleep apnea syndrome, might also represent a risk factor” for glaucoma. That study found that sleep apnea was “more prevalent” among glaucoma patients than among those without glaucoma, and concluded that there was an association, but stopped short of offering a reason why.⁴

A more recent study published in 2012 by the journal Clinical & Experimental Ophthalmology clarifies the connection a bit, reasoning that glaucoma is most likely a manifestation of the kind of “systemic risk factors” that can also cause sleep apnea. OSA upsets the normal cardiovascular balance of sleep; this affects the flow of blood to the head. And that, in turn, can “directly affect the optic nerve,” which could be a cause of glaucoma.⁵

Sleep apnea and glaucoma: Are the risks connected?

Not all sources agree about this connection between sleep apnea and glaucoma. The American Journal of Ophthalmology is on record stating that, “after adjustment for a number of important confounding factors, we found no significant relationship between sleep apnea (either treated or untreated with continuous positive airway pressure) and the development of OAG or NTG.” (OAG stands for open-angle glaucoma, NTG for normal-tension glaucoma).⁶

In making that statement, the journal also cites an earlier, larger study (“the largest published study to date”) that also found “no association between glaucoma and sleep apnea.”

So, there’s no clear consensus among researchers about the connection between sleep apnea and glaucoma. All the same, plenty of experts feel strongly that the two conditions are associated — and, on top of that, that the very possibility of this connection should prompt awareness that the presence of sleep apnea might mean an increased risk of glaucoma.

Sleep apnea “may be a modifiable risk factor for glaucoma,” said Eric Schmidt, OD, at an optometry conference in June, 2013, quoting a recommendation that “all patients with sleep apnea be screened for glaucoma.”⁷

What’s the sensible conclusion, here? Once again, it seems that treating sleep apnea at an early stage can help to limit your susceptibility to larger health issues, in this case, glaucoma — which, as the journal Sleep reminds us, is “one of the leading causes of blindness worldwide.”⁸

This blog post contains general information about medical conditions and potential treatments. It is not medical advice. If you have any medical questions, please consult your doctor.

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