Macular Degeneration: Symptoms, Diagnosis and Treatment

Macular degeneration, also called age-related macular degeneration (AMD), is the leading cause of severe vision loss in Australians over the age of 50. It affects the macula, the small central area of the retina responsible for detailed central vision used in reading, recognising faces, and driving. While macular degeneration cannot currently be cured, treatment for wet AMD can slow progression significantly and in many cases preserve or partially restore vision when started promptly.

What is the macula and why does it matter?

The macula is a small region at the centre of the retina, approximately 5mm in diameter, that is responsible for high-resolution central vision. It contains the highest concentration of photoreceptor cells in the eye, particularly cone cells, which are responsible for colour vision and fine detail. When the macula is damaged by AMD, central vision becomes blurred, distorted, or lost, while peripheral vision is usually preserved. This means patients with advanced AMD can still see to the side but lose the ability to read, recognise faces, or see fine detail clearly.

What causes macular degeneration?

Age is the single strongest risk factor. AMD is uncommon before age 50 and becomes progressively more prevalent with each decade. Other established risk factors include family history, smoking (which approximately doubles the risk), prolonged ultraviolet light exposure, cardiovascular disease, and obesity. Genetic factors play a significant role, with several gene variants associated with increased susceptibility identified in recent decades.

AMD is caused by a combination of ageing changes in the retinal pigment epithelium (RPE), the layer of cells that supports the photoreceptors, and the accumulation of waste deposits called drusen beneath the RPE. In wet AMD, abnormal new blood vessels grow beneath the retina, a process called choroidal neovascularisation (CNV), which can bleed or leak fluid and cause rapid central vision loss.

What is the difference between dry and wet AMD?

Dry AMD is the more common form, accounting for approximately 85 to 90 percent of all AMD cases. It is characterised by the gradual accumulation of drusen deposits and progressive atrophy of the retinal pigment epithelium. Vision loss in dry AMD is typically slow and may take years to become significant. There is currently no approved treatment that reverses dry AMD, though AREDS2 nutritional supplementation has been shown to reduce the risk of progression to advanced AMD in patients with intermediate disease.

Wet AMD, also called neovascular AMD, is less common but responsible for the majority of severe vision loss from AMD. It occurs when abnormal blood vessels grow beneath the macula and leak fluid or blood, causing rapid distortion and central vision loss. Wet AMD can develop at any stage of dry AMD and is a medical urgency. Prompt treatment with intravitreal injections of anti-VEGF medication is highly effective at slowing progression and in many cases stabilising or improving vision.

What are the symptoms of macular degeneration?

Early AMD is often asymptomatic and detected only on routine examination by an optometrist or ophthalmologist. As the condition progresses, symptoms include blurred or reduced central vision, distortion of straight lines (metamorphopsia), difficulty reading fine print, difficulty recognising faces, and a dark or blank spot in the centre of vision (scotoma) in advanced cases.

The Amsler grid is a simple self-monitoring tool that patients with known AMD can use at home to detect new distortion. Any new distortion, blurring, or blank spot in the centre of the Amsler grid should prompt urgent ophthalmology review, as these can indicate conversion from dry to wet AMD.

How is macular degeneration diagnosed?

Diagnosis is made by an ophthalmologist using a combination of clinical examination and imaging. Optical coherence tomography (OCT) is the key investigation, providing detailed cross-sectional imaging of the retinal layers and detecting fluid, drusen, and atrophy. Fluorescein angiography (FFA) and OCT-angiography (OCTA) are used to assess the vascular component of wet AMD and guide treatment decisions. Visual acuity and Amsler grid testing are used to monitor functional impact over time.

How is wet AMD treated?

The current standard treatment for wet AMD is intravitreal anti-VEGF injection therapy. Anti-VEGF agents (including ranibizumab, aflibercept, and brolucizumab) are injected directly into the vitreous cavity of the eye under sterile conditions and work by blocking the growth factor responsible for abnormal blood vessel development.

Treatment is typically initiated with a loading phase of three monthly injections, followed by ongoing injections at intervals determined by disease activity on OCT imaging. With modern treat-and-extend protocols, many patients can progressively extend the interval between injections as the disease stabilises. The injections are performed under topical anaesthesia and take only a few minutes. Most patients tolerate them well.

Early treatment is associated with significantly better visual outcomes. Any patient with suspected new wet AMD symptoms should be referred urgently to an ophthalmologist, ideally within days rather than weeks.

How is dry AMD managed?

There is currently no treatment approved in Australia that reverses or halts dry AMD. Management focuses on monitoring for progression and reducing modifiable risk factors. AREDS2 supplementation (a specific combination of vitamins C and E, lutein, zeaxanthin, and zinc) has been shown in large randomised trials to reduce the risk of progression from intermediate to advanced AMD by approximately 25 percent and is recommended for patients with intermediate or advanced AMD in one eye.

Lifestyle measures with established evidence include smoking cessation, UV protection with sunglasses, management of cardiovascular risk factors, and a diet rich in leafy green vegetables and omega-3 fatty acids. Patients with dry AMD should have regular OCT monitoring and be educated on Amsler grid self-monitoring so that any conversion to wet AMD is detected early.

Can you have cataract surgery if you have macular degeneration?

Yes, in most cases. Cataract surgery and AMD frequently coexist because both are age-related conditions. A cataract can reduce vision independently of AMD, and removing it may improve functional vision even in eyes with existing macular disease. However, the degree of visual improvement after cataract surgery is limited by the extent of macular damage, and managing patient expectations is an important part of pre-operative counselling.

In eyes with significant AMD, premium intraocular lenses such as multifocal or trifocal lenses are generally not recommended, as these lenses rely on good macular function to provide the full range of vision they are designed to deliver. A standard monofocal lens is usually the more appropriate choice. See our guide to intraocular lens options for more detail on lens selection.

For patients with coexisting cataract and AMD, coordinated management by a surgeon with experience in both conditions allows the timing and sequencing of treatment to be planned appropriately. I manage both cataract surgery and intravitreal injection therapy for AMD and can coordinate care for patients with both conditions.

When should I refer a patient for macular degeneration assessment?

GPs and optometrists play a critical role in early detection of AMD. Refer urgently (within days) for any patient with new onset metamorphopsia, new distortion on Amsler grid, sudden central vision loss, or a known history of dry AMD with new symptoms. Refer routinely for patients over 60 with reduced best-corrected visual acuity, drusen detected on fundus examination, or a strong family history of AMD.

For patients requiring intravitreal injection therapy for wet AMD, diabetic macular oedema, or retinal vein occlusion, I provide this service at Northern Eye Consultants in Bundoora. Patients with coexisting AMD and cataract can be assessed and managed for both conditions at the same practice.