You Want to Do WHAT to My Eye? Part 2
There are certain eye conditions where an injection into your eye might be recommended.
Injections into the eye, specifically into the vitreous or gel-filled cavity of the eye, are called intravitreal injections.
In Part 1 of "You Want to Do WHAT to My Eye?" we talked mostly about anti-vascular endothelial growth factor (anti-VEGF) injections. Anti-VEGF injections are probably the most commonly injected agents and they are used to treat wet age-related macular degeneration (ARMD), diabetic retinopathy, and retinal vein occlusion.
But there are other injections that may be used as treatment.
Another injected medication used in combination with Anti-VEGF agents to treat wet macular degeneration, diabetic retinopathy and retinal vein occlusion are steroids. Additionally, steroids can be used to treat inflammation, or uveitis, in the eye. There is a steroid implant called Ozurdex, that looks like a white pellet and can last up to 3 months in the eye. The downside of steroids is that they can increase eye pressure and cause progression of cataracts.
Antibiotics are another type of medication that can be injected into the eye. Sometimes an infection called endophthalmitis can develop inside the eye. This can occur after eye surgery or a penetrating injury to the eye. The presenting signs and symptoms of endophthalmitis are loss of vision, eye pain and redness of the eye. Bacteria is usually the cause of the infection, and antibiotics are the treatment. The best way to deliver the antibiotics is to inject them directly into the eye.
Another relatively new injection is Jetrea, an enzyme that breaks down the vitreous adhesions that may develop on the surface of the retina. As we age, the vitreous contracts away from the retinal surface. When this occurs over the macula, the region responsible for fine vision, the result is visual distortion. Jetrea is an injection that will dissolve the vitreous adhesions and relieve the traction on the retina. Prior to the advent of Jetrea, the only treatment would have been surgery to physically remove the vitreous jelly and traction on the retina.
The next time you visit your eye doctor and are told you need an injection of medication, it will likely be one of the above agents.
Article contributed by Dr. Jane Pan
You Want to Do WHAT to My Eye? Part 1
There are some eye conditions where your doctor might recommend an eye injection as a treatment option.
Injections into the eye, specifically into the vitreous or gel-filled cavity of the eye, are called intravitreal injections.
Anti-vascular endothelial growth factors (anti-VEGF) are probably the most commonly injected agents. They are used to treat wet age-related macular degeneration (ARMD), diabetic retinopathy, and retinal vein occlusion.
In these conditions, there are abnormal leaky blood vessels that cause fluid and blood to accumulate in and under the retina. This accumulation of fluid results in loss of central vision. The role of anti-VEGF agents is to shrink these abnormal vessels and restore the normal architecture of the retina.
There are three anti-VEGF agents widely administered: Lucentis, Avastin, and Eylea.
Lucentis (Ranibizumab) is FDA approved for treatment of wet ARMD, diabetic retinopathy, and vein occlusion. It is specially designed for injection into the eye and is a smaller molecule than Avastin so it may have better penetration into the retina.
Avastin (Bevacizumab) was originally approved by FDA for treating colorectal cancer. It is used “off-label” for the same treatment indications as Lucentis. Off-label usage of medication is legal, but pharmaceutical companies can't promote a medication for off-label use. The amount of Avastin needed for eye injections is a fraction of the amount used to treat colorectal cancer, therefore, the cost of ophthalmic Avastin is only a fraction of the cost of Lucentis. This means that Avastin needs to be prepared sterilely into smaller doses by an outside pharmacy prior to injection into the eye.
Eylea (Aflibercept) is the third anti-VEGF agent. It was designed to have more binding sites than Avastin and Lucentis so it may last longer in the eye than the former two. Eylea is FDA approved for treatment of wet ARMD, diabetic disease, and vein occlusion, and therefore, the cost of Eylea is similar to the cost of Lucentis.
Various studies have been performed to compare these agents. The most anticipated study was the CATT trial (N Engl J Med 2011; 364:1897-1908), which compared Avastin and Lucentis for the treatment of wet ARMD.
The study found that both had equivalent treatment effects on vision over the course of a year. In general, most ophthalmologists would consider all three agents to be very similar.
There is a thought that after prolonged injections, some patients may develop resistance to one particular agent but still respond to the other 2 agents. Therefore, your ophthalmologist will individualize your treatment.
Article contributed by Dr. Jane Pan
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