New treatment succeeds after laser fails in diabetic patients

This month's Ophthalmology, the journal of the American Academy of Ophthalmology, reports on use of bevacizumab (Avastin), to benefit diabetic patients with macular oedema as well as people who develop cystoid macular oedema after cataract surgery. Bevacizumab is also used to treat some cancers. Another study describes methods that could make cataract surgery safer for diabetic retinopathy (DR) patients. DR is the major threat to vision in working-age people, a problem that will only intensify if cases triple by 2050 as predicted.

DR damages the light-sensitive retina at the back of the eye, the area that transmits images to the optic nerve. In type 2 diabetes patients, retinopathy vision loss most often results from macular oedema (DME), swelling and thickening of the macula in the retina's center. Laser treatment is usually able to reduce vision loss, but widespread, diffuse DME (DDME) is often resistant to laser and other standard treatments.

Treating DDME with bevacizumab (Avastin), an anti-vascular endothelial growth factor (anti-VEGF) medication that inhibits abnormal blood vessels, was studied in 115 patients (139 eyes) by the Pan-American Collaborative Retina Study Group, led by J. Fernando Arevalo, MD, of the Caracas Central Ophthalmologic Clinic, Venezuela. Within one month of the initial intravitreal bevacizumab (IVB) injections, improvement could be detected. By the end of the 24 month follow-up period vision had improved in 51.8 percent of eyes, and 97.1 percent of eyes were either stable or improved. No serious adverse effects occurred. The Pan-American Collaborative Retina Study Group also reviewed the use of bevacizumab in patients with post-cataract surgery cystoid macular oedema (CME) who had not responded to standard treatment. Twenty to 30 percent of all patients develop CME, in which the macula swells as fluid-filled cysts form. Usually the condition resolves without treatment and causes no permanent vision loss, but in a small percentage of patients vision remains worse than 20/40 and treatment is needed. Standard treatments include steroids, non-steroidal anti-inflammatories (NSAIDs), other medications, or surgery.

The researchers reviewed the records of 31 patients (36 eyes) who were treated with at least one IVB injection and followed for 12 months between 2005 and 2007. At the study's outset the mean best-corrected visual acuity was 20/200, and at 12 months the mean was 20/80. Most eyes (72.2 percent) improved and the rest remained stable (27.8 percent). Macular thickness also decreased in most eyes. Patients who received two or more injections were significantly more likely to improve. No adverse systemic or vision side effects or outcomes were reported.

"Large, randomized controlled clinical trials are needed to confirm IVB's efficacy and safety in treating these conditions," Dr Arevalo said. "The results for DDME are very promising and suggest that combining anti-VEGF treatment with laser therapy may prove useful." He added, "Also, once further study is completed, unresolved CME post-cataract surgery should be considered for inclusion as an indication for use of IVB."