New Treatment Found to Reduce Vision Loss from Central Retinal Vein Occlusion
Scientists have identified the first long-term, effective treatment to improve vision and reduce vision loss associated with blockage of large and small veins in the eye. Two studies were part of the Standard Care vs. Corticosteroid for Retinal Vein Occlusion (SCORE) Study, a phase III clinical trial conducted at 84 sites and supported by the National Eye Institute (NEI) at the National Institutes of Health.
Hamidi: The second-most common cause of vision loss in this country results from a condition known as retinal vein occlusion, which is a blockage in the blood supply from the retina—the light-sensitive tissue in the back of the eye. The two main kinds of retinal vein occlusions affect different-sized blood vessels and are treated in different ways. A recent study, called the Standard Care vs. Corticosteroid for Retinal Vein Occlusion, or SCORE study evaluated methods of treatment.
Dr. Chew: The SCORE study really consists of two separate studies looking at two different aspects Ė but a similar disease in the same sort of spectrum Ė looking at retinal vein occlusions.
Hamidi: Dr. Emily Chew is Deputy Director of the Division of Epidemiology and Clinical Applications from the National Eye Institute. She explains that blood vessels in the eye come in two sizes.
Dr. Chew: One is sort of larger called the central retinal vein and the other is called the branch retinal vein, which are the smaller veins, smaller vessels in the eye.
Hamidi: Currently, no treatment exists for central retinal vein occlusion, a blockage of the major blood vessels. The SCORE Study was the first to compare the safety and effectiveness of an anti-inflammatory corticosteroid for central retinal vein occlusion.
Dr. Chew: The second study, the branch retinal vein occlusion, looked at the smaller vessels and because laserís always been thought to be important and also proven to be useful so we had to really do a head-to-head comparison with lasers.
Hamidi: At one year, central retinal vein occlusion patients who received a corticosteroid medication were five times more likely than those who did not receive treatment to experience a substantial visual improvement. But Dr. Chew points out that doses of both one and four milligrams we given.
Dr. Chew: The side effects for the 4 milligram was much higher than for the 1 milligram. So for that reason, 1 milligram would be the preferred treatment because the number of people who improve vision was very similar which was close to almost 30% and it was almost a 5 times increase or odds of improving your vision if you were given a steroid injection.
Hamidi: In the branch retinal vein occlusion — small vein occlusion study — which compared the use of laser versus steroids, the results suggested that laser is likely to be the more favorable treatment option.
Dr. Chew: And in fact, laser was almost identical to the treatment with steroid - that the vision improvement was very similar. And with laser, there isnít the side effect of the cataract formation and the increased pressure, so it makes it a more desirable treatment because of that. So if youíre going to test anything else youíre going to want to test it against laser — thatís really become the standard of care.
Hamidi: Dr. Chew explains that although laser treatment is as effective as steroids, without as many side effects, steroids should not be ruled out as a potential therapy for retinal vein occlusions.
Dr. Chew: Weíre not saying donít use the steroids because the steroid obviously was as effective as the laser. There may be times when the laser is exhausted and you canít get any better and maybe that might be helpful.
Hamidi: She adds that these steroids are not the same steroids that the public generally thinks about.
Dr. Chew: This is different from the steroid that, you know, people hear about out in the public Ė ones you use to make your muscles big, so this is a little bit different.
Hamidi: Dr. Chew acknowledges that while there is still much left to learn and to complement the results of the SCORE study, that this is one step in the right direction. For more information regarding the SCORE study visit www.nei.nih.gov/score. This is Anahita Hamidi, National Institutes of Health, Bethesda, Maryland.
About This Audio Report
Reporter: Anahita Hamidi
Sound Bite: Dr. Emily Chew
Topic: eye, vision, retina, retinal vein occlusion, branch retinal vein, central retinal vein, laser, steroid