Macular Degeneration News from Eyecatchers Optometrists

Age Related Macular Degeneration (AMD)

The macula is the central part of the retina, the light sensitive tissue at the back of the eye. AMD causes progressive damage to the macular resulting in central vision loss. Central vision loss can affect your ability to read, recognise faces, drive and see colours clearly.

What are the risk factors for developing AMD?

Age (Are you over 50?)
Smoking (Do you smoke, or have you ever smoked?)
Family history (AMD is highly hereditary)
UV radiation ( Do you wear sunglasses to protect your eyes from UV exposure?)

What are the symptoms of AMD?

Difficulty in reading or doing any other activity that requires fine vision
Distortion of vision - straight lines appear wavy or bent
Distinguishing faces becomes a problem
Dark patches or empty spaces in the centre of one's vision

There are two different types of AMD

"Wet" Age Related Macular Degeneration
"Dry" Age Related Macular Degeneration

"WET" Age Related Macular Degeneration (AMD)

“WET” age related macular degeneration (AMD) accounts for almost 50% of all patients registered with the NZ Foundation of the Blind, and is the leading cause of blindness in developed countries.

Both "wet" and "dry" ARM combined, constitute the most common visual reason for the elderly to:

stop reading and driving,
have accidents resulting in broken hips etc
become depressed
ultimately lose their self esteem and independence.

What is “Wet” AMD?

Ophthalmologists sometimes call "wet" AMD, exudative choroidal neovascularisation. It is characterised by a sudden loss of vision and is caused by abnormal blood vessels growing into the retina.

If you observe the diagram below you will note that there is a large raised, swollen region of the retina. This swelling is caused by exudation, originating from rogue blood vessels developing in the choriocapillaris, that punch through breaks in Bruck’s membrane and leak fluid (proteins and lipids) into the spaces between the retinal pigment epithelium cells (RPE). This produces a separation of the RPE or the sensory retina (the rods and cones)

Because these new vessels are rather fragile, they are quite disposed to haemorrhage. Leaking blood may percolate through all the layers of the retina and may even find its way into the vitreous cavity.
The end result of this process is a disciform macular scar resulting from consolidation of this intraretinal and subretinal blood.

Profound and extensive vision loss can occur very quickly, and therefore diagnosis and treatment is an urgent priority.

How can we recognise "Wet" AMD or a possible choroidal neovascular incident?

Acute onset of blurred vision in one eye coupled with distortion in vision would typically be the first signs of a problem.

Wet AMD occurs more frequently in the 60+ age group with acute onset of distorted and blurred vision, especially with near vision.
The disorder is bilateral approximately one third of the time, and the patient is more likely to notice subtle visual changes and distortion earlier in the second eye.
Patients at risk (including patients with "Dry ARM") should be given an Amsler grid chart by their optometrist and be taught to regularly look for changes in visual function (especially distorted vision or metamorphopsia) using this chart.

Modern treatment options for "Wet" AMD

Anti- VEGF (Anti-vascular endothelial growth factor) therapy has led to a revolution in the treatment of "Wet" ARM

Avastin and Lucentis are the two related anti-VEGF agents or VEGF inhibitors used as standard care in New Zealand.
VEGF inhibtors work by blocking the signal pathway in the formation of new blood vessels (angiogenesis) and prevent the growth and leakage of these new rogue choroidal vessels into the retina.
The treatment usually involves an initial "induction course" of three consecutive monthly injections of Avastin into the vitreous, followed by further treatment on a regular basis depending on the regime decided upon by your specialist.

The future looks to be exciting for anti-VEGF treatment.

A new medication called VEGF Trap-Eye, is a supercharged anti-VEGF agent which is predicted to have a much longer persistance of biological activity in the human vitreous than either Avastin or Lucentis. This means less frequent injections for the patient over time.
A more acceptable form of delivery of the drug would undoubtably be welcomed by the patient, and a number of medications are under development for topical use, ie drops.

"Dry" Age Related Macular Degeneration (AMD)

"Dry" AMD is the more common form of AMD, is often called atrophic AMD, and is more prevalent in the 60+ age group as well.

Currently there is no medical treatment for "Dry" AMD. However you can do a lot to reduce your risk of developing AMD

Have your eyes tested regularly and make sure that the macular is examined
Don't smoke - smoking greatly increases the risk of "Wet" AMD in particular
Keep a healthy lifestyle, Control your weight and exercise regularly ( cardio-vascular disease, high blood pressure and high cholesterol levels are not helpful)
Eat a healthy well balanced diet of dark green leafy vegetables (such as spinach since they are high in vitamin A and the carotenoids beta-carotene, lutein and zeaxanthin), fresh fruit daily, fish once or twice a week (tuna is a great source of the essential fatty acid omega-3), and a handful of nuts weekly.
Use dietary supplements for macular health including zinc and anti-oxidant vitamins such as beta catotene, Vitamin C and E and concentrated omega-3 supplimentation (Consult your doctor first before using dietary supplimentation)
Wear your sunglasses. Protect your eyes against UV radiation damage from sunlight exposure especially when young.

The carotenoid, lutein is found in green vegetables, especially spinach, as well as kale and broccoli. But egg yolks, although they contain significantly less lutein than spinach, are a much more bio-available source whose consumption increases lutein concentrations in the blood many-fold higher than spinach.
Although the mechanism by which egg yolk increases lutein bio-availability is not yet known, it is likely due to the fats (cholesterol and choline) found in egg yolk. Lutein, like other carotenoids, is fat-soluble, so cannot be absorbed unless fat is also present. To maximally boost your lutein absorption, it is suggested you enjoy your spinach, whether steamed, sautéed or fresh in spinach salad, with a little olive oil and a topping of chopped hard-boiled egg.

Omega-3 research. In 2007, a large multi-site study found that people who eat at least two servings of fish weekly are less likely to develop age-related macular degeneration (AMD), the leading cause of irreversible vision loss among people over 65 in developed countries.
Those in the study who consumed the highest levels of omega-3 fatty acids, primarily from fish, had a 39 percent lower risk of AMD compared with those who ate the least fish (Archives of Ophthalmology, May 2007).

More information on nutrition and the eye can be obtained from the excellent website http://www.allaboutvision.com/nutrition/