African Americans with diabetes risk vision loss

By Joene Hendry

NEW YORK (Reuters Health) - African Americans with type 1 diabetes have a high risk of loss of vision, new study findings show.

Poor control over blood sugar levels is "a very powerful risk factor for losing vision," lead investigator Dr. Monique S. Roy, of the University of Medicine and Dentistry of New Jersey in Newark, told Reuters Health.

Roy and co-investigator, Dr. Joan Sunice, noted that previous studies have examined the rate of visual impairments among Caucasians with type 1 diabetes, but, to their knowledge, there have been no similar studies conducted for a large group of African Americans.

To investigate, the researchers followed approximately 500 African Americans with type 1 diabetes over a period of 6 years to determine the rate of visual loss and associated risk factors.

At follow-up, they found that 4.3 percent of the study patients developed visual loss in their better eye, defined as a visual acuity of 20/40 or worse, and 0.6 percent became blind in their better eye, which was considered to be a visual acuity of 20/200 or worse.

Another 9.8 percent developed a doubling of the visual angle in their better eye, defined as the loss of 15 or more letters on the eye chart between the first and second visit. Another 13.5 percent showed a doubling of the visual angle in either eye, which was "particularly high," according to the report in the Archives of Ophthalmology.

In addition to poor control over blood sugar levels, the researchers found that older age, high protein levels in the urine (a symptom of kidney disease), and diabetic retinopathy -- a degenerative disease of the retina common among those with diabetes -- were all independent and significant predictors of vision loss over 6 years.

Roy notes that monitoring the severity of retinopathy in this patient population is crucial in identifying those who may require treatments to prevent severe vision loss. "Patients with kidney disease are also at a higher risk of losing vision than those who do not have kidney involvement," Roy said.

"Since African Americans with diabetes as a whole have poor blood sugar control," Roy notes, "a major effort to improve glucose control must be made by patients and physicians taking care of such patients."

SOURCE: Archives of Ophthalmology, August 2007.