Macular Degeneration

What is Macular Degeneration?

Age-related macular degeneration (AMD) is a retinal degenerative disease that causes progressive loss of central vision. Macular Degeneration is a leading cause of blindness in adults over 60.
The macula is the central part of the retina responsible for our most acute and detailed vision. With the loss of central vision, however, color vision and peripheral vision may still remain clear. Vision loss usually occurs progressively and typically affects both eyes at different rates.

Causes of Macular Degeneration

Age related macular degeneration occurs in two forms; Dry AMD and Wet AMD.

The majority of patients have the "dry" form, which causes a thinning of the macular tissues and disturbances in the pigmentation. There is uncertainty regarding the causes of dry AMD. Studies indicate that an area of the retina becomes diseased leading to a gradual loss of the light-sensing cells in the macula and a gradual loss of central vision.

Despite Wet AMD affecting only a minority of AMD patients it still causes 90% of blindness from the disease. As dry AMD deteriorates, Wet AMD can be caused by the growth of new blood vessels. The Wet form can involve bleeding in and under the retina, deposits, and scar tissue. Wet AMD causes rapid damage to the macula and can lead to the loss of central vision in a short period of time.

Diagnosis of Macular Degeneration

Typical Symptoms of Macular degeneration include:

Loss of central vision
Difficulty reading or viewing in detail
Distorted vision

Tests involved in diagnosing Age related Macular degeneration include the following tests:

Visual Acuity test
Amsler grid test
Ophthalmoscopy
Fundus photography
Fluorescein Angiography

The central vision may become blurred or distorted during the early stages of macular degeneration.

The advanced condition will often cause a blank patch or dark spot in the centre of vision. This makes activities like reading, writing and recognizing small objects or faces very difficult.

Treatments for Macular Degeneration

There is no proven medical therapy for dry macular degeneration but research indicates that high doses of vitamin supplements can help reduce the likelihood of severe vision loss in some patients with dry macular degeneration.

In certain cases of wet macular degeneration, laser photocoagulation is effective for sealing leaking or bleeding vessels. Laser photocoagulation does not normaly restore lost vision, but may prevent further loss of vision.

Treatments include:

Conventional Thermal Laser Treatment
Less than 20 percent of patients qualify for conventional laser treatment.

Photodynamic Therapy
The treatment is most effective in only a small number of wet macular degeneration patients.

Transpupillary Thermotherapy
Initial studies suggest that this may be an effective treatment, but limited information is available on how much better patients fare with this treatment.

Submacular Surgery
Submacular surgery involves the removal of effected tissue, however the surgery is likely to remove a layer of cells on the retinal, resulting in disappointing visual results.

Macular Translocation Surgery
This technique has not been proven but results are promising.