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