How many injections, on average, does a patient need for macular degeneration?
One common question from my patients with wet (neovascular) age-related macular degeneration (AMD) is how many injections one will need? After all, I have yet to encounter a patient that truely looks forward to their intravitreal injections. Most of them are hoping that they will be cured after a few injections.
The problem here is that the exact number and frequency of a patient's anti-VEGF injection frequency depend on the patient's clinical response to the treatment. It is impossible to predict this accurately ahead of time. However, large registry data give us some ideas on the average number of injections an AMD patient would need over time.
The Fight Retinal Blindness study on AMD injection frequency
This study, published in 2020, was based on 10 year data of neovascular AMD patients started on treatment between 2006 and 2008. Data on 712 eyes from New Zealand, Australia and Switzerland were collected.
It is clear from this data that the requirement for injections does not decrease over time. The number of injections is significantly higher in the Australian and New Zealand (ANZ) group (53 injections over 10 years, so 9.8 week interval on average) compared to the Switzerland group (42 injections over 10 years, so 12.4 week interval on average). The Australian and New Zealand group also has better visual outcome (0.9 letter loss vs 14.9 letter loss) and better disease control (38% active disease in ANZ group vs 69%).
IRIS registry data on AMD injection frequency
This is a USA based registry study involving 254655 eyes with neovascular AMD, at least one injection and two years of follow up.
Once again, the requirement of injections does not decrease over time. On average, patients in this registry were treated at slightly more than 12 week interval. Their visual acuity result is disappointing, compared to the Fight Retinal Blindness study above, with an average loss of 4.6 letter from baseline.
Interestingly, the researcher in this study showed in their modelling that each additional anti-VEGF injection after year one is associated with 0.68 letter gain in outcome. To me, this suggest that the patients here are under-treated with anti-VEGF with inadequate suppressed disease activity.
So, how many injections?
On average, most patients will require slightly more than five injections per year to keep their neovascular AMD stable and to maintain their vision. However, as I have mentioned before, some patients respond very well with no disease activity even with injections every 16 weeks, but some others will require injections every four weeks for a long time.
If you come to see me in my practice, I will work with you to find the most effective agent (Eylea, Vabysmo, Zaltrap, etc) to minimise the number of injections you need to control your disease. I will also look at alternative treatment (such as photodynamic therapy for polypoidal disease) to lessen the injection burden. Furthermore, most patients can tolerate a small amount of fluid (see FLUID study), so it is possible for me to increase your treatment interval safely in the presence of fluid in some instances.
Obviously, inadequately controlled neovascular AMD can severely damage your vision, so it is important that the disease process is adequately suppressed despite the desire of minimising the number of intravitreal injections.
About Dr Leo Sheck
Book your appointment now to see Dr Sheck
Dr Sheck is a RANZCO-qualified, internationally trained ophthalmologist. He combined his initial training in New Zealand with a two-year advanced fellowship in Moorfield Eye Hospital, London. He also holds a Doctorate in Ocular Genetics from the University of Auckland and a Master of Business Administration from the University of Cambridge. He specialises in medical retina diseases (injection therapy), cataract surgery, ocular genetics, uveitis and electrodiagnostics.
