What is anti-VEGF medication
Anti-vascular endothelial growth factor medications (Anti-VEGFs) are substances that stop blood vessels from forming or growing. Anti-VEGFs refer to a category of drugs which work by targeting a protein that is needed when new blood vessels form.
Blocking VEGF can reduce the growth of new blood vessels, slow their leakage and slow down vision loss. There are currently three drugs that have been used in the treatment of wet macular degeneration:
Lucentis gained EMEA approval in Jan 2007, this is based on extensive trials to show it is safe and effective. It can be used for all lesion types in wet AMD.
The trials have shown it to stabilise sight in more than 90 per cent of cases and improve sight in up to 40 per cent of cases.
The licence lays down a treatment plan which starts with three injections at four-weekly intervals followed by further injections based on the consultant's assessment of the patient.
Patients need to be monitored every four weeks.
In practice, patients receive on average eight injections in the first year and six injections in the second year.
Avastin has not been approved by the EMEA for the use of treatment in the eye as it has not gone through proper clinical trials to determine safety and how effective it is.
Ophthalmologists worldwide have been using Avastin off-label for AMD since 2006 ('off label' refers to prescribing medications for purposes for which they are not licensed). Avastin has been showing equal success in stopping new blood vessel growth and clinical observation suggest that its effectiveness and side effects are similar to those observed in Lucentis and Eylea.
Two large-scale long-term randomised controlled trials of Avastin have taken place and are due to report shortly. These results will allow questions about the safety of Avastin in the eye to be properly addressed.
Will I be suitable for treatment with anti-VEGFs
Not everyone with wet AMD will be suitable for anti-VEGF treatment. Anti-VEGF medication is most effective when treating blood vessels that are 'active' or 'leaking'. If wet AMD was diagnosed sometime ago, and there has been 'scarring' of blood vessels, then it is unlikely that a person will be suitable for treatment.
This is because the process of fluid and blood leakage from new blood vessels occurs for a while, and then dries up, eventually leading to scar tissue formation (similar to what happens when a skin wound heals). Scar tissue in the macula causes permanent vision loss and will not respond to any current treatment.
How anti-VEGF treatment is given
Anti-VEGF drugs are given as an injection into the vitreous (the jelly-like substance inside the eye). The injection will enter through the sclera (the white part of your eye).
It may be done in an operating theatre or a room designed for treatments.
Eyedrops will be administered into your eyes to dilate your pupils. This will allow the back of the eye to be examined more easily.
Local anaesthetic eye drops will be placed into the eye which is to be treated so that the injection itself will be painless. The eye and skin around it will be cleaned to prevent infection, and your face and the area around the eye will be covered by a drape to keep the area sterile. A small clip (a 'speculum') will be used to keep the eye open.
A few minutes later, the injection is given, this takes only a few seconds.
Your vision may be blurry for several hours afterwards due to the dilating eyedrops but this should improve by the next day.
You will be given antibiotic eyedrops to use for a few days following your treatment to prevent infection. Your eye may be red where the injection was given but that should disappear in a few days.
Your eye will feel comfortable by the next day and you may notice black swirls in your vision for a few weeks.
Possible complications of anti-VEGF treatmentsMost of the side effects involve the eye and are due to the injection procedure. These include:
Other side effects not related the eye include high blood pressure, nose and throat infection and headache. There is a theoretical increased risk of strokes with anti-VEGF, however the actual risk of stroke with anti-VEGF is unknown.
Tests after treatment
The ophthalmologist will order tests to be done following treatment. Optical coherence tomography is used to see if there is still fluid in the macula. This special photograph shows the layers of the retina in a cross section. Any fluid or inflammation can be seen using this photograph as well as the thickness of the retina. There is no dye or injection required for this type of photograph. Your visual acuity (how well you are able to read the chart) should also be checked at this time.
This combination of checking for leaking fluid and visual acuity would be used to determine if additional treatments are required.
Possible treatment outcomes
In various trials using Eylea and Lucentis, it was found that vision had stabilised, maintained or improved.In fact with Lucentis, there was a 33-40 per cent chance of achieving a clinically significant visual improvement.
This means that up to 40 per cent of patients in the study trial had an improvement in vision with a gain of 15 letters or more (approximately three lines) on the eye chart following treatment with an anti-VEGF compared to before starting the trial.