Injections are given to the eyes to treat certain eye conditions. These could be severe eye infections known as endophthalmitis. They could even be eye diseases related to diabetes. More on that later. Let us first understand the different types of drugs in these injections.
There are three types of injections
Following are the brand names of the common Anti-Vegf agents
VEGF stands for Vascular Endothelial Growth Factor. This chemical comes from many cells in the body and is used for certain critical bodily functions. Certain retinal conditions promote the growth of new blood vessels, which grow because of VEGF and are leaky. They cause swelling and bleeding in the retina, affecting vision.
Swelling and fluid collection in the retina is macular oedema. The macula is the central part of the retina and is the most crucial part of the eye. Macular oedema occurs in Diabetic Retinopathy. Retinal Vein Occlusions and ARMD also affect the retina. ARMD is age-related macular degeneration. It is also referred to as AMD.
Now, Anti VEGF drugs act against this Vegf. They are anti-vascular endothelial growth. By giving anti-VEGF injections into the eye, the VEGF level comes down, reducing the formation of these abnormal blood vessels. The leakage from these blood vessels comes down, and the swelling decreases. The vision thus improves.
AntiVegf injections were FDA approved for use in the eye in 2004. Since then, anti-vascular endothelial growth factor therapy has been the primary treatment for these retinal conditions. They cause fewer problems than their counterpart, steroid injections.
At one time, Steroid injections were the most common eye injections before the anti-VEGF eye injections.
The two Steroids injections commonly used these days are :
This steroid injection improves eye health in diabetic maculopathy. It is also used in CME (cystoid macular oedema) after cataract surgery and in certain inflammatory eye diseases.
Ozurdex is an injection in the eye. But it is a steroid implant that stays in the eye for four months. This eye injection releases the drug for prolonged periods. Ozurdex is used in Diabetic retinopathy and Retinal Vein Occlusions. It has no role in ARMD. Read more detailed information about Ozurdex.
Steroid Injections into the eye have two side effects. The first is they tend to cause a rise in eye pressure. This is known as Glaucoma. The second is they tend to hasten cataract formation. That is why after giving these injections, intraocular pressures are regularly monitored.
It is for these reasons that doctors prefer anti-VEGF drugs more than steroids. Eye Doctors use steroid injections when there is some inflammation. Steroids are also used when anti-VEGF injections don't have the desired result.
Compared to triamcinolone, Ozurdex injections in the eye have an added advantage. They have a longer duration of action. Ozurdex have more prolonged action than even anti-VEGF treatment.
Eye doctors use these to treat severe infections of the eye. These antibiotics are not available in the required concentration. Your ophthalmologist would prepare these medicines in the eye clinic.
Following are the conditions.
The common anti-VEGF drugs are
We will stick to the first names or the brand names in this discussion.
Patients with wet macular degeneration or wet AMD have a high chance of losing vision. These patients develop what is known as CNVM. CNVM is a choroidal neovascular membrane. Suppose treated with anti-VEGF drugs, these chances reduced. Patients regularly treated with Eylea, Accentrix, or Avastin injections maintain vision in the long term. These medications stop the leakage and bleeding linked with abnormal blood vessels. Leakage brings a primary cause of wet macular degeneration. And so, patients regularly treated with these drugs have better visual outcomes.
Clinical trials for all these agents have been conducted. These are discussed on the individual pages of these drugs.
Diabetic retinopathy (DR) is an important cause of vision loss. It is a leading cause in the population between 20 and 60 years of age. Among patients with DR, diabetic macular oedema (DME) is the most frequent cause of vision loss. This retinal disease represents a significant public health issue.
Before AntiVegfs, Laser photocoagulation was the mainstay of treatment for DME. Yet, these injections are safe and effective options for treating DME. They are the first choice for oedema that involves the centre of the macula. They reduce oedema and improve vision. Anti VEGF drugs also decrease the need for Laser treatment of the Macula.
These anti-VEGF treatments take place in the operation theatre. The injection in the eye consists of 0.1ml of the anti-VEGF drug.
The patient lies down on the OT table. After cleaning the area around the eye with betadine, a drape covers the patient's head and face. A plastic sheet then covers the patient's eyes.
A wire speculum opens the eye up. You look straight into the light on the ceiling. A measuring instrument called a calliper measures three millimetres from the limbus. The limbus is the outer edge of the cornea. These drugs are injected into the vitreous cavity, the back part of the eye, located behind the lens. It is known as the vitreous cavity as it contains the vitreous gel.
After this, your eye doctor gives the injection 3mm from the edge of the limbus. A 30g needle is what penetrates the eye.
Your eye doctor checks your eye pressure after giving the injection. Your ophthalmologist may feel that the eye pressure is high. If high, he then uses a 30 gauge or 26 gauge needle. He punctures the cornea to draw out some fluid from the front part of the eye. This reduces eye pressure.
After applying an antibiotic eye ointment, a patch covers the eye.
After the injection, usually, the patient meets the eye doctor. The eye doctor explains how to put in certain eye drops. These drops are antibiotics and prevent any eye infection. You can leave shortly after.
Because you have an eye patch, we recommend having someone with you. After the injection, you may feel gritty, which subsides in a few hours.
Sometimes there is a tiny bleed at the injection site, which leads to the eye becoming red. This redness may take up to a week to disappear.
Your vision will be slightly blurry. So we recommend that you don’t go to work after your injection. Some people may notice a small bubble in their vision due to the small amount of air present in the syringe. This air bubble disappears over the next few days as the air gets absorbed.
These anti-VEGF treatments take about two weeks to start acting. And for you to notice a visual difference. Sometimes, we see a response in as early as a few days.
You most likely had undergone an OCT eye test before the injection. About two weeks after the injection, this test is repeated. OCT machines can scan the retina at the same spot as the previous scan. Thus, looking at these scans, one can see the difference in the retinal swelling.
The following symptoms are COMMON after successful eye injections. These last for a day or so:
Duration of treatment depends on the disease. When treating wet AMD, therapy may go on for 3-5 months. Monthly injections go on for many months. If one stops treatment, there is a chance of recurrence. The swelling in the retina or bleeding in the retina may recur. And this could reduce vision all over again.
Recurrent swelling or bleeding damages the retinal cells. There is always some residual vision loss after treatment. Thus, staying on treatment becomes essential.
In some other diseases, treatment may stop after 1-2 years.
Researchers are investigating medications that last longer in the eye, which would reduce the burden of treatment in the future.
If you would like to read in detail about anti-VEGF agents, please click below.
Intravitreal injections are usually safe procedures. Yet, as with all procedures, there are some risks.
Severe complications are rare and include:
It is rare to lose vision because of an intravitreal injection. Rarely, you may develop severe pain, redness, or blurred vision. We then recommend that you call your nearest hospital.
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