Sleep apnea linked to blindness in diabetic patients

Severe sleep apnea is a risk factor for developing diabetic macular edema, a complication of diabetes that can cause vision loss or blindness, a study said.

For the study, the research team looked at the data from all patients diagnosed over an 8-year period at Chang Gung Memorial Hospital in Taiwan.

"Based on the results, we hope that more medical professionals will approach sleep apnea as a risk factor for diabetic macular edema," said study researcher Juifan Chiang from Taiwan.

This condition is called 'Diabetic Retinopathy' and is a leading cause of blindness in the US.

Diabetic macular edema is more difficult to treat in patients with severe sleep apnea, the researchers said.

When diabetics have poor control over the blood sugar levels, tiny blood vessels at the back of the eye can become damaged.

Sometimes, tiny bulges protrude from the blood vessels, leaking fluid and blood into the retina. This fluid can cause swelling or edema in an area of the retina that allows us to see clearly.

According to the researchers, sleep apnea may contribute to the development and worsening of Diabetic Retinopathy by increasing insulin resistance, elevating inflammation and raising blood pressure, all of which can damage the blood vessels at the back of the eye.

They found the rate of severe sleep apnea was significantly higher in patients with diabetic macular edema compared with those without diabetic macular edema (80.6 per cent vs. 45.5 per cent).

They also found that the worse their sleep apnea was, the worse their macular edema.

Severe sleep apnea was also more prevalent in patients who needed more treatment to control their macular edema.

The study was presented at the 123rd Annual Meeting of the American Academy of Ophthalmology in the US.