Age-Related Macular Degeneration

Abstract

Age Related Macular Disease is the leading cause of acquired blindness in the western world. Usually affecting people above the age of 50, this disease is classified into a nonexudative and exudative type of disease.
Typically patients with ARMD lose their central visual field but preserve their peripheral visual fields. The predisposing factors for ARMD include age, hypertension, smoking, family history of ARMD, sunlight, etc.
Most medical therapies focus on slowing the progression of the disease or accommodating the patient affected by ARMD.

Christian Haddad


Full Article

Age related macular degeneration is the leading cause of irreversible vision loss in North American patients aged older than 50 years. This is a degenerative process that is due to aging and smoking is associated with a more severe presentation. Usually, it is a disease of the posterior pole of the eye; hence it is characterized by the preservation of a functional peripheral vision with an impaired central vision. Changes to the retina can take place without or with drusen. Drusen are deposition in one of the retina’s layers (Bruch) and their effect on the vision is variable.

Neovascularisation

About one fifth of patients with age related macular degeneration will progress to a more severe stage of the degeneration where neovascularisation starts taking place. This is known as wet age related macular degeneration. This stage is associated with subretinal hemorrhage and acute visual loss. Of course if the hemorrhage happens closer to the fovea, the consequences would be worse in term of visual loss than if the same insult happened in the peripheral retina.

An imagining technique called fluorescin angiography, which consist of administrating an intravenous dye and then taking pictures of the fundus of the eye, is used to assess the extent of neovascular lesions and to perform the assessment before proceeding with laser surgery. New vessels, unlike old and mature ones, tend to leek fluroescin and hence are easily identified.

In the ophthalmology clinic, the patient should expect to perform Amsler grid test. With the chart held at an arm length from the patient, he will be presented with a grid and will be asked to note irregularities in the lines.  In addition, a direct ophthalmoscope will be used on a dilated pupil and the patient will be asked to look directly into the light source. The ophthalmologist will be looking on the retina for drusen, change in pigmentation, exudate and bleeding.

Seek Medical Care

Patient should seek medical care when there is a new onset of decreased visual acuity, visual distortion or blind spots.

Treatment consists of a daily dose of antioxidant and minerals for dry age related macular degeneration. Whereas argon photocoagulation is used for wet age related macular degeneration when the neovascularisation is taking place outside the fovea. If the neovsacularisation is taking place in the fovea a nonthermal phototherapy with verteprofin intravenous injection can be used to prevent visual loss. Currently various combination of medication that inhibits vessels formation in the eye are being tested, some are injected around the eye; other are injected inside the eye. In addition, some alternative medicine advertises solutions to age related macular degeneration. However, one should seek his ophthalmologist opinion before using any alternative therapy as this could interfere with other medications that he is taking or simply be inappropriate for his case.  Currently our optimal period of treatment is within 3 months of the onset of the degeneration since some vision can be restored and beyond this time frame the results are not as promising.

Finally despite the ophthalmologist efforts to preserve vision, some patients will progress to a low vision that will interfere with their daily activities. Hence, they will be offered some visual aids and will be followed by a low vision specialist that will rehabilitate them in order to allow them to function independently.

More reading source: National Eye Institute: Age Related Macular Degeneration Facts

http://www.nei.nih.gov/health/maculardegen/armd_facts.asp