The Role of Eye Injections in Treating Age-Related Macular Degeneration (AMD)

Understanding Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of permanent central vision loss in Australians over 50, affecting around 1 in 7 people over the age of 50 to some degree. It affects the macula — the small, high-resolution central area of the retina responsible for sharp, detailed vision used for reading, driving, and facial recognition.

AMD exists in two main forms:

• Dry AMD (atrophic):The more common form, accounting for approximately 85–90% of all AMD cases. It involves the gradual accumulation of drusen (fatty deposits) beneath the retina and progressive degeneration of the retinal pigment epithelium. There is currently no treatment that reverses dry AMD, though AREDS2-formulation nutritional supplements (containing lutein, zeaxanthin, vitamins C and E, and zinc) have been shown to reduce the risk of progression to advanced stages in patients with intermediate AMD.
• Wet AMD (neovascular):Accounts for approximately 10–15% of AMD cases but is responsible for the majority of severe vision loss. It occurs when abnormal new blood vessels — a process called choroidal neovascularisation (CNV) — grow beneath the macula. These fragile vessels leak fluid and blood, causing rapid distortion and deterioration of central vision. Without treatment, wet AMD can cause devastating vision loss within weeks to months.

Anti-VEGF Drugs for Wet AMD

Vascular endothelial growth factor (VEGF) is the key protein driving the abnormal blood vessel growth and vascular leakage that characterises wet AMD. Anti-VEGF drugs block this protein, halting the growth and reducing the leakage from existing neovascular membranes.

The anti-VEGF agents currently used in Australia for wet AMD include:

• Ranibizumab (Lucentis)— a VEGF-A antibody fragment; on the PBS for wet AMD.
• Aflibercept (Eylea)— a VEGF-A and VEGF-B and placental growth factor inhibitor; on the PBS for wet AMD, and may offer longer inter-injection intervals.
• Bevacizumab (Avastin)— a full-length VEGF antibody used off-label; widely used globally and in Australian private practice due to lower cost.
• Faricimab (Vabysmo)— the newest agent, targeting both VEGF-A and angiopoietin-2 (Ang-2); designed to extend treatment-free intervals further than older agents.

What the Injection Procedure Involves

Intravitreal injections are performed in a clinical setting under strict aseptic conditions. The procedure involves:

1. Topical anaesthetic eye drops to numb the eye surface.
2. Cleaning of the eye and surrounding skin with dilute povidone-iodine solution.
3. Placement of a sterile drape and speculum to keep the eye open.
4. A fine needle injection into the vitreous cavity of the eye — the injection itself takes less than 30 seconds.
5. Brief post-injection check of vision and eye pressure.

Most patients find the procedure much less uncomfortable than anticipated. The most common post-injection experience is a red patch on the white of the eye (subconjunctival haemorrhage) and a gritty sensation for one to two days. Serious complications — including infection (endophthalmitis) — are very rare but require urgent attention if the eye becomes significantly painful or vision drops sharply after an injection.

The Treatment Cycle for Wet AMD

Anti-VEGF treatment for wet AMD typically follows a structured protocol:

• Loading phase:Three monthly injections to rapidly suppress CNV activity and reduce macular fluid. This phase establishes the drug’s effect before transitioning to a maintenance schedule.
• Treat-and-extend: After loading, the interval between injections is gradually extended (e.g. from 4 to 6 to 8 weeks) as long as the retina remains stable on OCT. If activity recurs, the interval is shortened again. This approach aims to minimise injections while maintaining control.
• PRN (as needed): Injections are given only when fluid or new vessel activity is detected at monthly or bimonthly review visits. This requires frequent monitoring appointments even in periods without injections.

Outcomes and PBS Subsidy

Landmark trials such as ANCHOR and MARINA for ranibizumab, and VIEW 1 and VIEW 2 for aflibercept, established that anti-VEGF therapy stabilises vision in approximately 95% of patients and improves vision by 15 letters or more (three lines on a vision chart) in 30–40% of patients — outcomes never previously achievable with any AMD treatment.

The key message is that anti-VEGF treatment largely prevents further vision loss rather than fully restoring vision that has already been lost. Starting treatment promptly when wet AMD is first diagnosed gives the best possible chance of maintaining useful central vision.

In Australia, both ranibizumab (Lucentis) and aflibercept (Eylea) are subsidised under the Pharmaceutical Benefits Scheme (PBS) for wet AMD, significantly reducing the out-of-pocket cost for eligible patients.

Conclusion

Anti-VEGF eye injections represent one of the most significant advances in ophthalmology in the past three decades. For patients with wet AMD, they offer a reliable means of preserving the central vision needed for daily independence. Treatment is a long-term commitment, but with consistent monitoring and timely injections, the majority of patients maintain functional central vision for many years.

Frequently Asked Questions