Sleep disorder linked to eye disease

Research has already suggested that sleep problems can cause more than just tiredness - they have been linked to cardiovascular disease, cerebrovascular disease and metabolic disorders, and are also thought to raise the risk of obesity and diabetes.

To add to that worry new research from the U.S. now suggests that there may be a connection between sleep disorders such as obstructive sleep apnea and eye disease.

Researchers at the Mayo Clinic researchers say given the vascular risks associated with obstructive sleep apnea, this is not a surprise.

Lead author, Dr E. Andrew Waller, a Mayo Clinic pulmonologist and sleep specialist says there is little understanding of the mechanisms that link these disorders but the recognition of these associations is important for doctors, ophthalmologists, and sleep specialists.

Millions of people suffer from some form of sleep apnea, a potentially serious sleep disorder in which breathing repeatedly stops and starts during sleep. There are several types of sleep apnea but the most common is obstructive sleep apnea (OSA), which occurs when throat muscles relax and block the airway and numerous studies have identified OSA as an independent risk factor for the development of several medical conditions, including high blood pressure, which are related to impairments or alterations in a person's vascular (circulatory) system. As the eyes have their own complex and sensitive vascular system, they can sometimes signal and be affected by systemic vascular problems.

For the study the researchers conducted a search of literature which focused on sleep disorders and eye disease and found a variety of ophthalmologic conditions associated with obstructive sleep apnea such as: -

• Floppy eyelid syndrome which causes eyelids to turn inside-out spontaneously during sleep, causing excessive watering, stickiness, discomfort and blurred vision - while not a serious medical problem, it can indicate that a person also has OSA, which can lead to more significant health problems.

• Glaucoma - the second most common cause of blindness and of irreversible blindness - OSA is linked to two forms of this disease - primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG) and the researchers say the severity of glaucoma appears to correlate with the number and duration of apnea episodes in patients with OSA.

• Nonarteritic anterior ischemic optic neuropathy (NAION) - research has shown an increased incidence of OSA in people diagnosed with NAION where a sudden painless vision loss occurs in one eye, often noticed upon awakening which can cause irreversible vision loss.

• Papilledema - a swelling of the optic nerve in both eyes which usually occurs due to increased pressure within the skull and can lead to progressively worsening vision and in some cases, blindness and people with OSA may have a higher incidence of papilledema.

According to Dr. Waller, an awareness of the links between these eye conditions and OSA may lead to early diagnosis and appropriate treatment and for patients with OSA, a routine eye examination to evaluate for early signs of glaucoma, particularly in the setting of visual loss or change, is recommended.

Dr. Waller says patients with ophthalmologic diseases known to be associated with sleep apnea should be screened clinically for sleep apnea and referred to a sleep center if signs or symptoms are present.

The research is published in the November issue of Mayo Clinic Proceedings.