Washington, May 13 : Researchers at the University of Illinois at Chicago College of Medicine have shown that a low-vision therapy program that includes a home visit, counselling, assistive devices such as magnifiers and assignments to practice using them appears to significantly improve vision in veterans with diseases of the macula - the area of the retina with the sharpest vision.
Low vision not only affects daily function, but also increases the risk of depression, injury and an overall decline in health.
Most diseases that cause low vision are not curable.
"In most cases, impaired vision cannot be corrected and rehabilitation is the only option for regaining lost function for the patient with low vision. Low-vision rehabilitation aims to restore functional ability, the ability to perform tasks modulated by visual impairment," the researchers said.
For the study, Joan A. Stelmack, O.D., M.P.H., of the Edward E. Hines Jr. VA Hospital, Hines, Ill., and the University of Illinois at Chicago College of Medicine, and colleagues examined 126 patients with low vision and diseases affecting the macula who were eligible for Veterans Affairs (VA) services.
They randomly assigned the participants to one of two groups.
In one group, patients received a vision therapy program incorporating a low-vision examination, counselling, assistive devices such as magnifiers and five weekly sessions provided by a low-vision therapist to teach use of the assistive devices and other adaptive strategies.
They were also assigned homework to ensure they used the devices outside of therapy.
In the other group, participants were placed on a wait list for the therapy program and received no treatment for four months, an amount of time veterans might normally wait to receive such services.
After four months, the 64 patients in the treatment group received an average of 10.46 hours of face-to-face vision therapy.
And researchers found that they experienced a significant improvement in all aspects of visual function, including reading ability.
They also found that among the 62 patients in the group that did not receive therapy, vision and functional ability declined over the four-month follow-up.
"Significant improvements in functional ability for mobility, visual information processing, visual motor skills and overall ability also were seen in the treatment group; small losses in these functions were observed in the control group," the authors said.
"At least 10 hours of low-vision therapy, including a home visit and assigned homework to encourage practice, is justified for patients with moderate and severe vision loss from macular diseases," they conclude.
"Because the waiting-list control patients demonstrated a decline in functional ability, low-vision services should be offered as early as possible," they added.
The study is published in the May issue of Archives of Ophthalmology, one of the JAMA/Archives journals.