Age-Related Macular Degeneration

Age-related macular degeneration is deterioration of layers of the retina and choroid as people get older.

The retina is a thin layer of nerve tissue that lines the inside of the eyeball. It senses light, similar to a sensor in a camera, and passes these signals to the brain via the optic nerve. Age-related macular degeneration (AMD) is deterioration of layers of the retina and choroid as people get older. AMD results in loss of visual acuity, the sharp central vision, due to gradual damage of the central retina (also known as the macula). It is the leading cause of central vision loss in people over the age of 50 in developed countries such as Australia. There are various factors that are linked to development of AMD but the main factor is age. There are two main types of macular degeneration: Dry AMD and wet AMD.

Dry AMD

In dry AMD, the features that can be seen in the macula include ‘drusen’ and ‘atrophy’. Drusen are pale yellow lesions that form beneath the retina, and are waste products of cells that are not adequately cleared by the ageing layers in the eye. Atrophic areas are areas of retina that waste away during the course of dry AMD progression. Larger areas of atrophy are called ‘geographic atrophy’. This is the advanced type of dry AMD.

Wet AMD

In wet AMD, there are new blood vessels (termed ‘neovascularisation’) that leak in the macula and damage the vision quicker than dry AMD. The neovascularisation can cause a sudden or gradual worsening of the central vision, or can cause distortion of straight lines. On examination and high-definition imaging of the retina there may be presence of blood or leak at the macula. Eventually the leaking blood vessels can cause scarring of the macula, resulting in a ‘disciform scar’, which causes permanent loss of central vision.

More Information

Risk factors

Some of the known risk factors for developing AMD include:

  • Age – the strongest risk factor
  • Cigarette smoking
  • Family history of AMD
  • Caucasian race

There are other possible risk factors, but their link to AMD is less well known.

Diagnostic testing

The main diagnosis of dry or wet AMD is through both history and examination with a slit lamp with your Optometrist or Ophthalmologist. To classify the type of AMD, and to get approval for treatment from the Australian government, further tests are often needed. The tests include:

  • Optical Coherence Tomography (OCT scans)
  • Fluorescein Angiography (FA)
  • Micro-perimetry Field testing (MAIA)

The above tests can help guide management of AMD.

Treatment

Retinal specialists at Queensland Eye Institute are actively involved in research for treatment of both Dry and Wet AMD. At any given time we are involved in multi-centre trials on new medications that may work better for certain patients who are unsuitable for or have failed other treatments. Please discuss this with us at your appointment.

Wet AMD

Treatment for Wet AMD has been revolutionised in recent years due to development of drugs that target the abnormal new blood vessels in the eye (neovasculariation). Collectively, the family of medications that have been effective in controlling neovascularisation are ‘Anti-Vascular Endothelial Growth Factor (Anti-VEGF)’.

Queensland Eye Institute (QEI) has Retinal Specialists who specialise and work pre-dominantly on retinal diseases such as AMD. At QEI we have access to all latest medications that have been approved in Australia for use in AMD. Often the regime for these medications are monthly for the first few months, and then adjusted based on each individual’s response.

Dry AMD

A certain group of patients with drusen, the earliest form of dry AMD, can benefit from nano-pulse laser treatment to slow down progression of their AMD. At the QEI Clinic we can assess and treat these patients as necessary. At this stage, no treatment can prevent vision loss from geographic atrophy, the advanced form of Dry AMD.

A vitamin supplement formula may delay or prevent a type of AMD from progressing onto advanced forms. This formula is known as the Age-Related Eye Disease Studies (AREDS 2) formula, and most optometrists and pharmacists are able to supply this vitamin formula.

Other lifestyle measures that will help include a healthy balanced diet and exercise routine, stopping smoking, and frequently reviewing the eyesight in each eye for distortion with an ‘Amsler Grid’. A regular check-up with your optometrist every year or more frequently depending on the type of AMD is recommended.

Next step

If you have any concerns about macular degeneration and the management of this condition, please obtain a referral letter from you Optometrist or Family Doctor and make an appointment with our retinal specialists. They will be happy to manage your condition with you.

For more information please visit https://www.mdfoundation.com.au/

 

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