ATLANTA, Dec. 8 -- Prevalence of retinopathy, glaucoma, and other vision problems related to diabetes are projected to rise dramatically over the next four decades.

With rising diabetes rates, the number of Americans 40 and older with diabetic retinopathy will triple by 2050, Jinan B. Saaddine, M.D., M.P.H., of the CDC here, and colleagues reported in the December issue of the Archives of Ophthalmology.

The number of diabetic patients with cataracts and glaucoma will likely double or triple as well, the researchers said.

Their projections, using National Health Interview Survey and census data, suggested higher rates than earlier predictions, which had not accounted for recent changes in diabetes rates, Dr. Saaddine said.

Factors contributing to this change include "a steady increase in the total U.S. population, an increase in the average age of the population, and disproportionate growth in the number of Hispanics and blacks, among whom the prevalence of diabetes is higher than among whites," the researchers wrote.

Improvements in diabetes management could curtail the growth rate of eye problems, but the benefits for survival would likely counteract this effect by prolonging the average duration of diabetes, they noted.

The rise in diabetic eye complications will undoubtedly increase demand on the healthcare system and should add impetus to improving ophthalmologic screening among diabetes patients, Dr. Saaddine said.

Earlier studies have shown only about 50% to 70% of diabetics get the recommended annual dilated eye examinations.

"Simply increasing this cost-effective intervention might reduce the rate of vision loss and blindness associated with diabetes," the researchers said.

The most important strategy, though, would be to curb the incidence of diabetes, Dr. Saaddine said.

The Census Bureau forecasts a population of 402 million by 2050, and the CDC has predicted 48 million will have diabetes, the researchers said.

They calculated rates of eye disease among people with diabetes based on a constant prevalence rate determined from published studies that rates for eye disease followed projected changes in diabetes prevalence.

They estimated that the number with diabetic retinopathy of any severity would grow to 16.0 million in 2050, up from 5.5 million in 2005.

The prevalence of vision-threatening diabetic retinopathy was likewise expected to nearly triple from 1.2 million to 3.4 million over this period.

The researchers projected even greater growth among blacks and Hispanics, particularly among those 65 or older.

For older white women, though, cases of diabetic retinopathy were expected to peak earlier, in 2030.

Glaucoma associated with diabetes will universally increase across demographic groups, the researchers calculated. By 2050, prevalence was projected to reach 1.45 million compared with 0.33 million in 2005.

Again, glaucoma rates were expected to rise most among blacks 50 or older and among Hispanics across all age groups, including an 11- to 12-fold increase among those 65 and older.

Cataract prevalence in persons with diabetes will reach 9.94 million in 2050, up from 2.96 million in 2005, the researchers projected.

Although increases were expected across age and gender categories, the rates were particularly dramatic for blacks 75 and older, with 637% growth expected for women and 677% for men between 2005 and 2050.

The researchers acknowledged that the study was limited by assuming a constant prevalence of eye problems at the 2005 level and use of general population prevalence estimates for glaucoma and cataracts rather than diabetes-specific estimates.