Knowing the SCORE for treating retinal occlusions

Investigators weigh the standard of care against corticosteroids for retinal vein occlusions

When it comes to central retinal vein occlusions, injections of the corticosteroid triamcinolone can be effective in preserving vision in some patients.
Recent study results published in the September 2009 issue of Archives of Ophthalmology indicate that for patients with certain blockages, a daily 1-mg dose of triamcinolone may be a viable option, according to Michael S. Ip, M.D., associate professor or ophthalmology, University of Wisconsin, Madison.
“Occluded ocular veins are considered to be the second most common cause of vision loss from retinal vascular disease,” Dr. Ip said. There are two different types of occlusion that can occur—central or branch retinal vein occlusion. “As the name suggests, central retinal vein occlusion involves more of the ocular fundus because the main or central retinal vein is occluded,” Dr. Ip said. “In a branch retinal vein occlusion one of the tributary veins is occluded, so a smaller area of the ocular fundus is involved.”

Early occlusion treatments

Different treatments have been tried over the years for these occlusions. For central retinal vein occlusion there was no proven effective therapy. “People tried a variety of treatments such as vitrectomy surgery, injecting intravitreal tissue plasminogen activator, and radial optic neurotomy,” Dr. Ip said. “While a number of treatments were tried, nothing was proven to be effective for that condition.” As a result, observation was considered to be the standard of care.
For branch retinal vein occlusion, there was a proven treatment—laser photocoagulation. This was standard treatment at the time investigators initiated the SCORE (standard of care versus corticosteroid for retinal vein occlusion) study in 2003. “At the time, standard therapy for branch retinal vein occlusion was grid photocoagulation and grid laser for retinal swelling or macular edema secondary to branch retinal vein occlusion,” Dr. Ip said. “We initiated the SCORE study because we felt that perhaps there were other therapies that would bring additional benefits.”
Back then, there were a number of therapies developing and one that looked promising to investigators was the intravitreal injection of triamcinolone. While in the short-term there were reports that this was very effective with patients showing visual improvements and reductions in retinal swelling, there was a potential downside. “It seemed that there could be a risk of side effects,” Dr. Ip said. “Patients could get an infection in the eye and endophthalmitis from the injection, as well as cataracts and glaucoma from the steroids.” In addition, some patients on the triamcinolone appeared to become refractory to this treatment.

Weighing the options

Investigators set out to determine if a lower 1-mg dose of triamcinolone might be as effective as the 4-mg dose that was being arbitrarily administered in occlusion cases. “The SCORE study compared the intravitreal injections of two doses of the triamcinolone—the 1-mg dose and the 4-mg dose,” Dr. Ip said. “We also compared the two triamcinolone doses to the standard of care at the time for CRVO which was observation and for BRVO which was laser treatment.”
Results were promising. Investigators found that the steroids were equally effective at improving vision in the patients with central retinal vein occlusion. “We found that both doses gave five times greater chance of seeing better at a year than if the patient didn’t get an injection,” Dr. Ip said. When it came to safety, however, the 1-mg dose was clearly preferable. “With the 1-mg dose, in terms of needing cataract surgery it was very similar to the observation group,” Dr. Ip said. “It makes it relatively easy to recommend the 1-mg dose as applied in the SCORE study for patients who have CRVO.”
In the case of BRVO both doses of triamcinolone fared as well as the laser treatment. “Given the fact that with laser you don’t have to put a needle into the eye, we feel that it has a superior safety profile and therefore if it’s as efficacious as the steroid then it’s easy to recommend,” Dr. Ip said.
Overall, Dr. Ip sees this as an interesting time for the treatment of retinal vein occlusions. At the same time the SCORE results were published, recent trials looking at Lucentis (ranibizumab, Genentech, South San Francisco, Calif.) and a steroid implant (Allergan, Irvine, Calif.) for retinal occlusions were presented at the 2009 Retinal Congress in New York. In addition, other therapies are now in the mix. “Ozurdex (Allergan) has been FDA approved and is available, and I think Lucentis is going to receive FDA approval for this,” Dr. Ip said. “It’s welcome news to our patients that we have multiple choices for central retinal vein occlusions.”
Still, he believes that the SCORE study results will continue to prevail as the standard of care for treatment of branch retinal occlusion. “In my opinion given the results of the SCORE study I think that laser photocoagulation probably is the best of all the treatment options as an initial therapy for patients with branch retinal vein occlusion,” Dr. Ip said.

Editors’ note: Dr. Ip received research support from Allergan (Irvine, Calif.) and the National Eye Institute (Bethesda, Md.). He serves on the data safety monitory committee for QLT (Menlo Park, Calif.) and Sirion Therapeutics (Tampa, Fla.), and has financial interests with Notal Vision (Tel Aviv, Israel).

Contact information

Ip: msip@wisc.edu