A study published in JAMA claims that treating proliferative diabetic retinopathy with an injection in the eye of the drug ranibizumab improves visual acuity not worse than panretinal photocoagulation at two years. The findings are being presented at the annual meeting of the American Academy of Ophthalmology.

Retinopathy: The Need For A New Method

Proliferative diabetic retinopathy (PDR) is a more advanced form of the disease. It leads to complete loss of vision in diabetic patients, and about 12,000 to 24,000 of such cases are reported every year in the US. Presently, the standard method of treatment is Panretinal Photocoagulation (PRP), a procedure that uses a laser.

However, this procedure can result in permanent peripheral visual field loss and debilitating night vision, along with enhanced diabetic macular edema (DME) which is characterized by swelling of the retina in diabetes mellitus due to leaking of fluid from blood vessels within the macula. Hence, alternate forms of treatment are highly desirable.

Conducting An Analysis

Intravitreous (in the vitreous fluid behind the lens of the eye) anti-vascular endothelial growth factor (VEGF) agents tend to reduce the chances of diabetic retinopathy from worsening, and in turn increase the likelihood of improvement. Adam R. Glassman, M.S., of Jaeb Center for Health Research, Tampa, Fla., and the Writing Committee for the Diabetic Retinopathy Clinical Research Network, along with his colleagues assessed 305 adults with PDR. Both eyes were studied for 89 patients and one eye was randomly assigned to each group (PRP treatment or anti-VEGF agent), making a total of 394 eyes.

PRP treatment involved in to three visits and treatment with anti-VEGF agent (ranibizumab) consisted of an intravitreous injection at the start of the study and after every four weeks according to a structured retreatment protocol. Eyes in both treatment groups could receive ranibizumab for DME.

Promising Findings

Results showed that intravitreous ranibizumab gave a prespecified noninferiority outcome in terms of visual acuity at two years. However, there was no statistically significant difference between the two treatment groups – 53 percent of the PRP group also received ranibizumab injections for DME.

Findings of the PRP group revealed increased peripheral visual field loss, greater number of vitrectomies (removal of the gel [vitreous] from within the eyeball), and enhanced development of DME. On the contrary, no systemic safety concerns regarding ranibizumab were identified in the main outcomes.

“Although longer-term follow-ups are needed, ranibizumab might prove to be a reasonably alternate treatment, at least through two years, for patients with PDR”, the authors conclude.