Oxygen, vision & diabetes

Oxygen delivered through the nose may improve poor vision caused by macular edema.

A pilot study by scientists at Johns Hopkins and the National Eye Institute have said that oxygen delivered through the nose may improve poor vision caused by diabetic macular edema.

Diabetic macular edema is the fluid build up in the part of the eye responsible for central vision.

In a study of five diabetic patients with persistent macular aedema, breathing supplemental oxygen for three months reduced fluid buildup and swelling in the macula and, in some cases, improved visual acuity.

Researchers think that the therapy could be used in conjunction with laser treatments that also improve oxygenation in the retina to provide long-term stability in these patients.

"The results were really dramatic," said Peter A. Campochiaro, senior author of the study.

The researchers studied nine eyes of three men and two women in the age group of 52 to 69, who had type 2 diabetes for an average of nine years. All patients had received at least one laser eye treatment and despite an average of 2.7 treatments per eye, all eyes except one had persistent edema.

Patients were given 4 liters per minute of oxygen delivered by small tubes inserted into their noses, and instructed to use the oxygen continuously every day for three months, removing the tube only when taking showers. They were provided with a stationary oxygen concentrator for home and portable oxygen tanks to use outside the home.

After three months, excess thickness of the macula was reduced by an average of 43 percent in all nine eyes. Excess thickness of the fovea, the part of the eye responsible for the sharpest vision, was reduced by 42 percent, and macular volume dropped by 54 percent. In addition, three eyes improved in visual acuity, with the ability to see two lines higher on a standard eye chart.