What is My Risk for Macular Degeneration

Age-related Macular Degeneration and Inheritance

Age-related macular degeneration (AMD) has a number of risk factors which include age, smoking, gender, race, ultra-violet light exposure, diet, obesity, hypertension, family history, eye color and inactivity.   Some of these are external causes and can be controlled, but others are due to inheritance and cannot.   These inherited risk factors are genetic which is becoming an important factor in predicting who will not only get  macular degeneration, but also who will get the advanced form of age related macular degeneration.

Types of Macular Degeneration

Advanced AMD is of two forms, dry and wet.  Dry AMD is slowly progressive and over time will lead to significant loss of vision by tissue damage/aging.  It is treated conservatively with nutritional supplements, and is monitored for possible transition to wet AMD.  Wet AMD is differs from dry AMD, in that it is associated the ingrowth of abnormal blood vessels. These blood vessels leak/bleed causing damage to the macula.  This loss of vision can be sudden and severe, and when it occurs in one eye, the risk of the fellow eye is at increased risk.

Genetic Risk Of Macular Degeneration

Genetic studies have identified many genetic markers which lead to macular degeneration, however there are 6 markers that are most highly associated with advanced AMD, which results in severe central vision loss. One marker is complement factor H (CFH), which is related to the inflammatory pathway.  The second is tissue inhibitor of matrix metalloproteinase 3 (TIMP3), which causes degradation of the extracellar matrix resulting in neovascularization.   The third and fourth are age-related maculopathysusceptibility 2 (AMDS2) and nicotinamide adenine dinucleotide dehydrogenase subunit 2 (ND2), both associated with oxidative phosphorylation and oxidative stress. The fifth and sixth are hepatic lipase C (LIPC) and high-density lipoprotein cholesterol (HDL-C) which affect carotenoid metabolism and xanthophylls transport. Analysis of these 6 markers in patients at risk for AMD will place each in one of 5 categories of risk (MR1 to MR5).

Patients classified as either MR1 or MR2 are at the lowest risk.  They constitute approximately 80% of the entire US population, and have an estimated 2.5% or 9.5% risk of developing advanced AMD before the age of 80 years, respectively.  MR3 patients have an approximate risk of 25%; MR4 patients, 45%; and MR%, 75%.  MR3-MR5 patients are in the high risk category and require closer follow-up, home self monitoring with the Amsler grid and use of nutritional supplements.

Why Testing and Monitoring is Important

The importance of close monitoring of those patients in the high risk categories is crucial because the earlier advanced wet AMD is diagnosed the better chance of successful results with the current treatments.  Therefore, patients at high risk need to be seen more frequently by their retinal specialist, who will evaluate the status of their macula and when necessary, perform the diagnostic tests to determine the early onset of wet AMD.  Once this is determined, treatment can be initiated immediately.

With AMD becoming an increasing health problem in the United State the importance of knowing one’s genetic risk can help in delaying severe vision loss by instituting early treatment.  This, in turn, will decrease the societal financial burden and improve the individual’s long term quality of life.

Mel Chen, MD

Retina Specialist

Sarasota Retina Institute

Sarasota, Florida

 

 

 

 

Jody Abrams, MD, FACS
Oculoplastics/Neuro-ophthalmology
Sarasota Retina Institute
Sarasota, Florida 34239

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  1. […] Recently Drs. Levy, Torres, and Rivero were asked to speak at the local Macular Degeneration Group meeting. They were happy to inform the group of recent changes in the treatment for macular degeneration. […]