A study by a KU School of Medicine ophthalmologist finds that LED light may help patients with diabetic retinopathy

April 23, 2014

By Donna Peck

Johnny Tang, M.D.

Diabetic retinopathy is the leading cause of blindness in adults. It affects up to 45 percent of all patients who have had diabetes for 10 years or more. Poor blood sugar control can be especially detrimental to small blood vessels such as those in the eye. High blood glucose levels may damage the tiny blood vessels in the retina - or light-sensitive tissue of the eye - of people with diabetes and cause swelling, bleeding and other retinal abnormalities, which may lead to vision impairment and blindness.

A new study by a University of Kansas School of Medicine ophthalmologist has found that a handheld LED light device may help reduce swelling in patients with diabetic retinopathy. The study by Johnny Tang, M.D., an associate professor of ophthalmology, was recently published in The British Journal of Ophthalmology.

Tang says traditional treatments for diabetic retinopathy are usually invasive, such as injections of medicines into the eye, laser surgery or even vitrectomy surgery to remove scar tissue from the inside of the eye. A few years ago, he read about a research study in Great Britain which used a near-infrared spectrum light called photobiomedulation (PBM) to help reduce mouth ulcers in cancer patients undergoing chemotherapy.

"I wondered if the same technology could work on the eye ulcers in patients with diabetic retinopathy," Tang says.

Tang began pre-medical experiments on the idea in 2007. He took retinal cell lines from animals and induced them to become diabetic by soaking them in glucose. When he exposed the cells lines to the PBM light, more of the cells lived than died.  He then began a study using the light therapy on animals with diabetic retinopathy. Diabetic rats exposed to PBM light once a day showed a significant reduction of diabetes-induced retinal cell death compared to diabetic rats that were not exposed to PBM.

"It appeared that the level of inflammation in the diabetic retinal cells was significantly decreased in after exposure to the PBM light," Tang says.

Tang then designed a small trial with a group of his patients who were experiencing a form of diabetic retinopathy. He gave the patients a handheld battery-powered device that emitted PBM light.

"The patients who were given the light were instructed to hold it about two inches from the study eye and shine the light for 80 seconds, twice a day," Tang says.

When he followed up on the trial patients, Tang says, "the eyes that were treated with the light saw improvement in diabetic retinopathy, while the untreated eyes stayed the same or continued to deteriorate."

His next step is to get funding to conduct a bigger clinical trial.

"This treatment has a tremendous potential to provide a non-invasive and cost-effective option to help many of the 5.3 million Americans and patients outside the Unites States who suffer from diabetic retinopathy," Tang says. "I am hopeful that it will give patients new hope when it comes to treating this devastating eye disease."

Last modified: Apr 29, 2014