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​​​Sleep apnoea has link with eye diseases like glaucoma

Of the various sleep disorders, obstructive sleep apnoea (OSA) appears to have the strongest association with eye problems, including glaucoma, a common cause of blindness in Singapore.

A study by the Singapore National Eye Centre​ (SNEC) and the ​Singapore General Hospital​’s (SGH) Sleep Disorders Unit​ found that 8 per cent ​of patients with moderate to severe OSA have open angle glaucoma with normal pressure.

In comparison, the pre​valence of this type of glaucoma is 1.4 per cent and 3.2 per cent for all forms of the disease in the general population. Glaucoma can cause vision loss, and accounts for 40 per cent of blindness in Singapore. But as with heart disease, while the association between these eye conditions and OSA are clear, the reasons for the connection are not yet understood, said Dr Desmond Quek, Consultant, SNEC, who is co-author of the study.

“One possibility is that OSA compromises blood flow to the optic nerve. This then creates a transient drop in oxygen supply and increases resistance to blood flow, thus damaging the optic nerve,” said Dr Quek.

The study, conducted between 2013 and 2014, recruited 100 patients suffering from moderate to severe OSA. According to Dr Quek, comprehensive ophthalmic examinations using advanced imaging techniques were done to detect glaucoma even in its early stages.Eight of the patients had glaucoma.

Blindness can be prevented if glaucoma is detected and treated in its early stages. Eye drops may be prescribed as the first line of treatment to lower eye pressure and prevent further nerve damage. If eye drops fail to lower the pressure, more invasive forms of treatment like surgery may be required.

Apart from glaucoma, OSA has been shown to be associated with floppy eyelid syndrome (eyelids that are easily everted or turned inside out), non-arteritic anterior ischaemic optic neuropathy (a painless sudden loss of vision) and papilloedema (a swelling of the optic disc), said Dr Toh Song Tar​, Senior C​onsultant, Department ​of Otolaryngology​, and Director, Sleep Disorders Unit​, Singapore General Hospital​​​ (SGH). In patients with ischaemic optic neuropathy, 70-8​0 per cent have OSA, Dr Toh added.

Common sleep disorders seen at SGH include insomnia, movement disorders during sleep, and circadian rhythm sleep disorders.

“A lack of sleep can have a negative impact on energy, mood, concentration, and overall health,” said Dr Toh, noting that an estimated 30 per cent of chronic diseases are related to poor sleep health.

See previous page ​​to find out how severe sleep apnoea is linked to heart disease​.

Ref: O17