Dr Simon ChenCataract & Retina SurgeonWhat age-related macular degeneration is, the difference between the dry and wet forms, how it is assessed, and what eye injections involve.
The macula is the small central area of the retina that gives sharp, detailed vision for reading, driving and recognising faces.
Age-related macular degeneration (AMD) is a condition in which this central area wears and changes with age. It affects central vision, not the edges, so people rarely lose their sight completely, but reading, faces and fine detail can become difficult.
There are two forms. Dry AMD is the more common and usually progresses slowly, as deposits called drusen build up under the macula and the retinal cells gradually thin. Wet AMD is less common but can change vision quickly, when fragile new blood vessels grow under the macula and leak fluid or blood. Dry AMD can turn into wet AMD, which is why any new distortion needs a prompt check.
Because the macula is at the centre of the retina, the symptoms sit in the middle of whatever you look at.
Lines of print, door frames, tiles or the edge of a road look wavy, bent or kinked, most often in one eye.
A blurred, grey or missing patch in the centre of vision, so the middle of a face or a word is hard to make out while the edges stay clear.
Print needs more light or magnification, colours look less vivid, and faces can be harder to recognise across a room.
A new central blur, distortion or missing area needs prompt assessment. It may indicate wet AMD or another eye problem. Contact the clinic when you notice a change rather than waiting for your next appointment.
Slide each picture to compare typical vision with the change described. Illustrations are indicative, not a diagnostic test or a prediction of vision after treatment.
Most common from the sixties onward and increasingly so with each decade.
The strongest avoidable risk factor. Stopping helps at any age.
A parent or sibling with AMD raises the likelihood, so relatives are encouraged to have their macula checked.
Cardiovascular risk factors are linked with AMD, and looking after them helps the eye too.
A diet rich in green leafy vegetables and fish is associated with lower risk. Supplements are discussed individually.
Once one eye is affected, the other is watched more closely.
General information. Individual risk is discussed at the consultation.
Most of the assessment is looking, measuring and scanning. It does not hurt.
After a vision test, dilating drops enlarge the pupil so the macula can be examined properly. An OCT scan (optical coherence tomography), which uses light to map the layers of the retina in fine detail, shows drusen, thinning, fluid or bleeding under the macula, and is repeated over time to track change. Retinal photographs are usually taken, and in some eyes a dye test (angiography) is used to show leaking vessels.
Dr Chen explains what the scan shows, which form of AMD is present, and what that means for your vision and treatment.
A self-check between visits does not replace an examination.
An intravitreal injection places medication directly into the vitreous, the clear gel that fills the eye, so it reaches the macula at a useful concentration.
For wet AMD the medications block the signal that drives abnormal blood vessels to grow and leak under the macula. They are not a one-off. Treatment is given as a course: usually a series of injections about a month apart at first, then at intervals set by how the macula looks on the OCT scan. Many people continue treatment, often at a longer interval, for years.
Dr Chen was principal investigator in international clinical trials in macular degeneration, including the VIEW2 trial. He discusses the medication, the schedule and the trade-offs with each patient before treatment begins.
Limitations: the injections treat wet AMD but do not cure it; they do not help dry AMD; treatment continues for as long as the eye needs it; and, as with any injection into the eye, there is a small risk of infection, retinal detachment or raised pressure. Suitability is discussed at the consultation.
Wet AMD is treated with intravitreal injections, described above. The aim is to dry the leak under the macula and protect the vision you have; the interval between injections is set by the OCT scan at each visit. Suitability, the medication and the schedule are discussed individually.
No injection or operation reverses dry AMD. Care centres on regular monitoring with OCT, not smoking, a diet rich in green leafy vegetables and fish, looking after general health and, for some people, a specific vitamin formulation where the examination suggests it may help. Above all, any new distortion or smudge needs prompt review, because it may signal a change to the wet form.
Good lighting, magnification, larger print and strong contrast all help make the most of the vision you have. Low-vision services can be arranged when they are useful, and driving requirements are discussed openly.
Suitability for any treatment is decided at the consultation, based on the examination and scans. General information, not a guarantee of outcome.
Bring these, and anything else on your mind. Write the answers down, or bring someone who can.
AMD affects central vision. Side vision is preserved, so people keep the ability to get around, although reading and faces can become difficult when the centre is affected. Treatment for wet AMD aims to protect the vision you have.
Usually monthly at first, then the interval is set by how the eye responds on the OCT scan. Some eyes need injections for years; others can be spaced out. The schedule is reviewed at every visit.
The eye is numbed with drops and the injection itself takes seconds. Most people describe pressure or a brief sting rather than pain, and some grittiness afterwards from the antiseptic.
Yes, in a proportion of eyes, and usually with a noticeable change: new distortion or a central smudge. That is why self-checks between visits, and prompt review of any change, matter.
Specific vitamin formulations have been studied in AMD and may be suggested for some people at a particular stage of the condition. They are not a treatment for everyone and are discussed individually.
Family history increases the risk, so close relatives are encouraged to have their macula checked at routine eye examinations.
Appointments and enquiries through Vision Eye Institute, Chatswood.
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