Macular Degeneration

Macular Degeneration occurs at the part of the retina that provides central, detailed, and colour vision. A person who is typically affected by AMD may have difficulty performing everyday tasks requiring good, precise central vision, such as reading, watching TV, undertaking daily activities, and driving, however, less precise peripheral vision remains unaffected.

The location of the macula is at the very back of the eye, in line with your visual axis. The eye functions similarly to a camera; light pass through the cornea and lens onto the retina, then the retina absorbs this light and converts this light into an image.

The retina is lined with photoreceptor cells, which allow us to see fine detail and colours. Underneath this layer is the Retinal-Pigment-Epithelial Layer (RPE). The proper functioning of the RPE layer is essential for photoreceptor health. Broadly there are two types of AMD, dry and wet. All patients with this condition will have dry AMD where there is a build-up of waste material underneath the RPE layer known as Drusen, an early sign of AMD. Later, the photoreceptors may be damaged causing retinal thinning. In approximately 25% of patients AMD may progress to the wet stage where, small blood vessels may grow under the retina and bleed, causing further damage to the eye and the patient’s vision.

There are several factors known to be associated with an increased risk of developing macular degeneration.

• Age - Aging is the primary contributor to AMD development.
• Smoking – Smoking can cause oxidative stress, inflammation and decreased macular pigment.
• Family History – Having a close blood relative such as siblings and/or parents who have AMD carries a significantly increased risk of developing AMD.
• Genetics – Many studies are being published regarding genetic variants and linkages in AMD.
• Diet - There is some association between the incidence of macular degeneration in certain communities and eating a diet higher in processed foods and lower in fish and vegetables. A diet rich in omega 3 fatty acids (fish and nuts), vegetables rich in lutein (particularly dark green leaf and yellow vegetables), and zeaxanthins in deeply coloured fruits/ berries may be beneficial as these food groups contain nutrients and naturally occurring antioxidants known to reduce the progression of AMD
• Environment - Ultraviolet and near blue light wavelengths from excessive sunlight exposure has also been implicated in causing macular degeneration, but is yet to be proven through thorough research. However, the use of sunglasses and hats is a good precaution to limit ocular exposure given the high levels of sunlight and UV light in Australia

Treatment dry macular degeneration is difficult. Wet AMD is now treated with injections of Anti-Vascular Endothelial Growth Factor (Anti-VEGF) into the eye. There are several types available (subsidised through the PBS).The drugs block VEGF receptors, thereby reducing abnormal blood vessel growth, eliminating accumulated fluid and retaining the health of the photoreceptors. Early intervention is essential in reducing the risk of further vision loss in patients with Wet AMD.

• Gradual impairment of vision with reduced definition and detail, reduced colour discrimination and contrast, and distortion of images (metamorphopsia).
• Prolonged adaptation time when changing between dark and bright light conditions.

A modified Amsler Grid Chart is a very useful modality to monitor for early disease progression. An Amsler Grid and more information can be found on the Macular Disease Foundation of Australia website by clicking here:

To check for macular changes using an Amsler grid at home:

1. Place on your reading glasses and hold the chart at a normal reading distance from your eyes.
2. Cover your left eye with your hand, and look at the black dot in the middle of the chart with your right eye.
3. Observe the surrounding grid for any distortions/waviness of the grid lines or blurred/darkened patches on the grid. If you notice any of these visual symptoms, please book in for an ophthalmic assessment as soon as possible.
4. Repeat the above steps covering your right eye and viewing the chart with your left eye.

If an Amsler grid is not available, look at objects that are straight such as tiles on the floor or door frames. Watch out for any parts of the object that are missing or waviness or distortion in the object.

In the early stages of Wet AMD these symptoms develop more rapidly. Prompt intervention and treatment is required in order to preserve your vision, please call your eye specialist to make an appointment as soon as possible if you develop rapid onset of these symptoms.