Macula Month (May) raises awareness about macular degeneration, one of the most common causes of irreversible blindness. We chatted to Professor Mark Gillies, Director of the Save Sight Institute’s Macula Research Group, to find out what macular degeneration is and how research at SSI could help improve treatment options and patient outcomes.
What is the macula and what is its function in the eye?
The macula is the central part of the retina (which is like the film of a camera) that sees what you are actually looking at. It’s vital for reading, driving, recognising people – in short, it’s essential for central vision.
What is macular degeneration and how does it affect a person’s vision?
Macular degeneration is a process that often begins in a person’s mid-50s. It may result in loss of central vision, but this usually takes decades, if it happens at all. Patients may not notice they have the condition until their vision has been affected – they may have had it for years before they come to see a doctor.
There are three types: early, intermediate and advanced. Only advanced macular degeneration significantly affects vision. This may be from bleeding or ‘wet’ degeneration, or from macular atrophy or ‘dry’ macular degeneration where the macula wastes away. The bleeding is now treatable with injections of ‘VEGF’ inhibitors, but macular atrophy is still, unfortunately, untreatable.
What causes macular degeneration and who is at risk of being affected?
It is said that about three-quarters of the risk is genetic – it runs strongly in families. The main environmental risk factor is smoking and, to a lesser extent, a diet which is poor in fish and leafy green vegetables. It typically affects women more often than men because women live longer.
How common is macular degeneration? Are rates increasing or decreasing?
It’s one of the commonest causes of irreversible blindness, although blindness is not as common as it once was as injections for ‘wet’ macular degeneration were introduced 15 years ago. Rates of early degeneration are increasing as the population ages.
How is macular degeneration treated or managed?
Currently, injections are used to treat macular bleeding. They give good results but usually must be continued indefinitely, even over a period of decades. There are a number of clinical trials that are trying to find an effective treatment for macular atrophy, but none have succeeded as yet. Patients with macular degeneration should see an eye care professional in case there are other issues that need attention and may also affect their sight, such as cataracts and glaucoma.
What research is the Macula Research Group conducting into macular degeneration?
The Clinical Trials Unit is currently involved in roughly twenty trials of new agents for wet or dry macular degeneration.
The Laboratory Research Unit has established ways to grow the human macula in the lab for the first time. This is significant, as we have previously used animal models, but often find that treatments that work in animals do not work in humans. We are using these ‘macula explants’ to expedite the translation of discoveries in the laboratory into clinical practice. We are currently developing tiny lipids called ‘nanolipids’ to carry treatments to retinal cells and repair specific cell pathways that we believe will boost the macula’s natural defences against degeneration.
The Fight Retinal Blindness! registry has been tracking the treatment outcomes for ‘wet’ macular degeneration for 15 years. We have helped established the best and most effective treatment regimens that generate the best results ('treat and extend') and what can be achieved under the conditions in Australia which are favourable because the drugs are fully reimbursed by the government and there are enough eye doctors to give the injections.