More detailed description about age-related macular degeneration

Age-related macular degeneration is the most frequent cause of blindness in patients over the age of 65. It affects men and women similarly, the average prevalence is about 100 cases per 100.000 people. The disease is common for whites (Caucasians), but rare for African-american.

The most important mechanism for developing the disease is the aging process of the retina. The aging retina looses its ability to regenerate, which causes typical symptoms to develop. When the disease advances into the late stages, gradual vision loss can occur.

Reasons for disease development

Risk factors are aging, belonging to the Caucasian race, a positive family history, smoking, hypertension, intensive exposure to sunlight and obesity. Also, an important factor is genetic predisposition.

Symptoms

Age-related macular degeneration is a disease, which develops gradually and does not hurt. Symptoms differ between the wet and dry form. In the dry form, symptoms develop slowly, while in the wet form, visual acuity can deteriorate very quickly. In both forms, patients have troubles with distinguishing the colours and they recover slowly when they are exposed for longer periods to intense sunlight.

The most important early sign of dry form of the disease is blurred vision. Details, such as words in a book or faces, became unclear. Often very strong light improves vision. As disease progresses, patients can notice small blind spot in the centre of visual field which can increase in time.

The most important early sign of wet form of the disease is distorted vision (metamorphopsia). Consequently, straight lines seems curvy. In wet form, central blind spot can occur as well.

Diagnosis

The diagnostics of age-related macular degeneration begins with a thorough patient's history and a good physical examination. To confirm the disease, the best method is to perform a test with the Amsler grid. Other specific test are also useful, such as visual acuity testing, examination of the eye fundus and special computerised tests such as fluorescent angiography and optical coherence tomography.

Prevention

Prevention of the disease is virtually impossible, as early changes in the macula are part of the physiological aging process. It is important that once the changes in the macula have been discovered, the disease is monitored carefully to prevent it from advancing into late stages. Annual check-ups at ophtalmologists are recommended to reduce the possibility of permanent loss of central vision.

Therapy

There are different types of treatment for both forms of the age-related macular degeneration. The disease can be treated with medications, but surgical techniques are much more efficient.

Medications

Antioxidants – studies shows that antioxidants, such as beta caroten, and vitamin C, significantly reduce the progression of the disease as well as vision loss.
Vascular endothelial growth factor inhibitors – are new drugs which are used for wet forms of the disease. Visual acuity is stabilized and even improved in up to 95% of patients.

Operations

Laser therapy – is used in advanced stages of the disease, but only for classic wet forms, which are confirmed with flurescein angiography. The downside of laser therapy is that after 2 years in 40 to 75% of the patients the disease recurrs.
Photodynamic therapy – is also used in the advanced stages. The procedure is done 5 to 6 times during 3 months, in order to stabilize the remaining visual acuity.

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