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Aging eyes and macular degeneration
25 March 2015 - In Canada and other high-income countries the widespread availability of potent combination anti-HIV therapy (commonly called ART or HAART) has tremendously reduced deaths from AIDS-related infections. Furthermore, researchers increasingly expect that some ART users will live into their 80s. Therefore, among patients whose immune systems have improved and stabilized thanks to ART, the focus of care will likely eventually shift to the prevention and treatment of conditions related to the aging process. One such complication affects the eye and is called age-related macular degeneration (AMD). Before we tell you about AMD, we first provide some background material about the eye.
About the eyes
Light enters the eye and is focused by the lens so that light lands on the retina. The retina is the portion of the eye that is sensitive to light. It converts light into electrical signals that are sent to the brain.
Near the centre of the retina lies a group of cells called the macula. This is the most sensitive portion of the retina. The macula is needed for sharp vision of objects that are straight ahead (central vision).
About AMD
AMD is a relatively common condition that can occur in people who are 50 years and older (though it is most common among people 65 and older). In cases of AMD the macula degrades, resulting in changes in vision. There are two forms of macular degeneration, as follows:
- dry AMD cells in the macula slowly break down, resulting in blurry vision
- wet AMD extra blood vessels grow under the retina; these vessels tend to be weak and leak fluid that ultimately results in injury to the macula
There are three stages of AMD, as follows:
- early AMD a few small or medium-sized yellow deposits (called drusen) are under the retina; visual loss is uncommon in early AMD
- intermediate AMD large drusen are present and a degree of vision loss may have occurred
- late AMD large drusen are present and a degree of vision loss has occurred
Not everyone with early AMD will develop late AMD. However, because changes in vision can sometimes be sudden, it is important to have regular eye examinations, particularly for people over the age of 50.
Although no therapy can reverse wet AMD, an eye care professional can help discuss ways of screening for AMD and slowing it down with treatment options. In cases of dry AMD, your doctor may recommend certain specific supplements that have been found to slow AMD in clinical trials.
Some risk factors for AMD cannot be changed, such as the following:
- age
- genes people with close family members (parents and siblings) who have AMD
- race white people are at increased risk
With professional help and advice, the following risk factors can be changed:
- smoking
- obesity
- higher-than-normal cholesterol
- cardiovascular disease
- elevated blood pressure
- chronic inflammation
- a diet lacking colourful fruit and vegetables
The next CATIE News bulletin reports on a finding of AMD in HIV-positive people.
Sean R. Hosein
REFERENCES:
- Holz FG, Schmitz-Valckenberg S, Fleckenstein M. Recent developments in the treatment of age-related macular degeneration. Journal of Clinical Investigation . 2014 Apr;124(4):1430-8.
- Nussenblatt RB, Lee RW, Chew E, et al. Immune responses in age-related macular degeneration and a possible long-term therapeutic strategy for prevention. American Journal of Ophthalmology . 2014 Jul;158(1):5-11.
- Schramm EC, Clark SJ, Triebwasser MP, et al. Genetic variants in the complement system predisposing to age-related macular degeneration: a review. Molecular Immunology . 2014 Oct;61(2):118-25.
- Aronow ME, Chew EY. Age-Related Eye Disease Study 2: perspectives, recommendations, and unanswered questions. Current Opinion in Ophthalmology . 2014 May;25(3):186-90.
- Adamus G, Chew EY, Ferris FL, et al. Prevalence of anti-retinal autoantibodies in different stages of age-related macular degeneration. BMC Ophthalmology. 2014 Dec 8;14:154.
- Chew EY, Clemons TE, Agrón E, et al. Ten-year follow-up of age-related macular degeneration in the age-related eye disease study: AREDS report no. 36. JAMA Ophthalmology . 2014 Mar;132(3):272-7.
From Canadian AIDS Treatment Information Exchange (CATIE). For more information visit CATIE's Information Network at http://www.catie.ca
Source: CATIE: CANADIAN AIDS TREATMENT INFORMATION EXCHANGE
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