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Can eye injections stave off blindness or prevent further vision loss due to retinal conditions? A study by the Singapore National Eye Centre (SNEC) published in the Ophthalmology Retina journal in late 2019 found that injections of anti-VEGF (vascular endothelial growth factor) drugs could arrest vision decline in about 95 per cent of patients with exudative age-related macular degeneration (AMD). The anti-VEGF drugs block the growth of abnormal blood vessels in the eye that affect vision.
Read more: What is age-related macular degeneration (AMD)? Learn more here.
“Anti-VEGF injections, the most common among intravitreal (IVT) jabs, or a shot of medicine into the eye, are a game changer in treating exudative AMD,” said Dr Shaun Sim (below), Associate Consultant, Cataract and Comprehensive Ophthalmology Department, SNEC.
Exudative AMD is an irreversible condition that occurs when new blood vessels grow from beneath the macula, the central area of the retina, which is the lightsensing nerve tissue at the back of the eye. It is one of the leading causes of blindness in people aged 50 and above.
In light of this, SNEC is exploring ways to improve awareness of the effectiveness of IVT injections, and to make it less burdensome to get these jabs so that patients adhere to the treatment regime.
Before anti-VEGF drugs became available, laser was used to treat exudative AMD, but outcomes were not favourable for patients. “With the advent of anti-VEGF injections, we are able to preserve vision and maintain stability of their condition,” Dr Sim said.
Patients need to return regularly for subsequent injections of the anti-VEGF drugs under a “treat and extend” regime, in which the intervals between jabs are extended depending on their responses to the treatment.
Initially, the injections are administered once a month for three months. “If the patient’s condition is stable after the initial loading phase, we move on to an extension phase, where the interval between each jab is lengthened by either two or four weeks,” said Dr Sim.
A significant number of patients have had successfully treatment extensions of up to 12 to 16 weeks, and the results for exudative AMD have been positive. “More than 70 to 80 per cent of our patients are able to improve their vision with anti-VEGF injections across a two-year period,” Dr Sim added.
The same treatment process applies for other conditions treated with anti-VEGF injections, such as retinal vein occlusion (a blockage of the small veins that carry blood away from the retina) and diabetic retinopathy (an eye disease that affects people with diabetes). These two conditions may also be treated with intravitreal steroids.
IVT injections of antibiotics, antifungals or antivirals are also given to certain patients with eye infections.
In 2020, SNEC carried out nearly 19,000 IVT injections, a significant increase from approximately 5,000 in 2013. “Our patients are getting more and more aware of their condition, thanks to increased screening and improved health literacy,” said Dr Sim.
Minimal pain involved
The thought of getting an injection straight into the eyeball can be harrowing and having to return for frequent treatments can also be daunting. However, Dr Sim said that the patient experiences minimal pain and that the entire process is quick — approximately five to 10 minutes.
During the process, the eye is first numbed with anaesthetic eye drops. The eye and eyelid are then cleaned to remove bacteria. An eyelid speculum is used to keep the eye open. The patient is then directed to look away from the needle while the injection is administered at the sclera (white part of the eyeball).
Severe side effects, if any at all, are rare. Some patients may experience dry eyes and discomfort. This can be simply relieved with eye drops, or may even resolve on its own. Others may encounter a tiny pinpoint blood clot on the surface of the eye at the needle entry point, but this will usually heal within one to two weeks. Infections are very rare, said Dr Sim.
A patient education programme is available at SNEC for patients to learn more about IVT injections and other information related to the procedure. SNEC has also produced a new set of printed brochures with improved legibility by using larger fonts and adding more colours. These brochures are placed in a bag printed with an Amsler chart. The chart helps patients identify any abnormalities in their vision should they see distortions in the square-shaped grid.
SNEC is currently working with centres internationally to conduct trials to assess patients’ response to newer anti-VEGF drugs that offer durable visual outcomes with fewer injections.
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