Vision Preservation, Your DNA, and Ocular Vitamin Supplements
For a general overview of Age-Related Macular Degeneration (ARMD or AMD), please refer to our article on that topic here.
For patients and their families with AMD, there is important new information with regard to preserving vision with ocular vitamin supplements, individualized for maximum effect with the use of new testing protocols partly based on genetics.
AREDS (Age-Related Eye Disease Study) is a multi-center, long-term study of thousands of patients who were diagnosed with AMD and the effects of various treatment modalities, which ended in 2001. There are various reports that were issued about the results, which are available for viewing on the internet, but the ground-breaking result showed that high-dose supplements with antioxidants plus zinc reduced the risk of AMD progression in patients with moderate to severe disease in at least one eye.
What became known as the AREDS Formulation of vitamin supplements contained these vitamins and minerals:
- 500 mg Vitamin C
- 400 IU Vitamin E
- 15 mg beta-carotene
- 80 mg Zinc
- 2 mg Copper
Later, AREDS 2 altered this formulation to substitute lutein and zeanxanthin, in lieu of the beta-carotene after finding that this was also safe and effective.
There are two basic types of AMD, known as “dry” and “wet.” Most patients initially are diagnosed with the dry type, which causes changes in the pigmentation under the retina, deposits, and local areas of retinal atrophy. About 20% of dry AMD cases progress into the wet form, which is characterized by the growth of new blood vessels into the retina and ocular space, which are extremely fragile and usually break and bleed, causing permanent tissue damage and destruction of vision.
Preservation of functional vision is the key. AREDS showed that patients who took ocular antioxidants (in the form of the AREDS Formulation, noted above) had a significantly better chance to preserve their vision over time.
Because AMD is a multifactoral disease, involving various factors including genetics, current AMD status, and lifestyle and environmental variables, it can be problematic deciding which factors are most important and which can be considered not useful in a particular, individual patient.
Pharmacogenetics is the science of how genetic variation affects an individual’s response to therapy, and is used to optimize treatment outcomes, determine an appropriate course of action and avoid harmful effects in those patients who have specific genetic markers that would have a negative reaction to supplements or specific ingredients in them, and medications.
Recently, pharmacogenetic analysis of the AREDS dataset showed evidence that components of the AREDS Formulation may be beneficial OR harmful, based on the patient’s specific genes. Almost half of the AREDS population would have derived greater benefit from an ocular vitamin formulation other than the AREDS Formulation. This investigation suggests that genotype-directed vitamin formulations would have more than doubled the decrease in AMD progression rates, compared to the AREDS Formulation. It should be stated clearly here that this type of genetic testing was not then available to modify treatment.
The illustration photograph shows both types of macular degeneration, dry (whitish deposits and holes) and wet (red splotches formed by bleeding into the retina).
Genetic testing and studies have now revealed that some patients, because of their genetic types, would get the best outcome if they were on different supplement plans than the AREDS Formulation; some patients who lacked certain genes did well on the AREDS Formulation supplements, while others showed a detrimental effect of adding zinc to the mix, while yet others got better results on zinc alone, without the other antioxidants.
In other words, their genetic types determined which supplements they should take to get the maximum benefit to their vision in the long term. About half of patients with moderate to severe AMD in at least one eye seem to derive more benefit from a therapy regimen other than the AREDS Formulation.
Taking into account other variables such as the current status of AMD, their age, their genetic markers across 12 AMD-associated genes, their Body Mass Index (BMI), their smoking history and their education, it is possible to generate a prediction of AMD progression over two, five and ten years, with an amazing accuracy rate of almost 90%. Patients are given a score for their level of Macula Risk (MR), reflecting the prognosis for progression and visual loss.
ArcticDx, a reliable evaluator of DNA, uses DNA from a simple mouth swab and other factors listed above results in a Macula Risk (MR) scores ranging from 1 to 5; an MR score of 1 indicates only a risk of about 2% that they will develop significant vision loss, while a 5 indicates the need for early intervention and treatment. (See sidebar)
Accordingly, a large group of patients who have had their DNA tested by ArcticDx and have MR scores of two or one are predicted to have only a 10% chance of developing vision loss from AMD, while those in risk categories MR -3 to MR-5 are at greater risk, and would benefit from more frequent eye exams (every six months), education about AMD, routine use of an Amsler Grid (a simple printed grid on a card, which can be used by the patient to monitor their own vision at home), lifestyle and dietary changes and taking preventive ocular supplements accordingly.
An early diagnosis and treatment of wet AMD to save the vision in the first eye as well as the second is the key to best visual preservation. Delay in diagnosis and treatment in patients with moderate to severe MR scores is destructive of vision over the long term; even a matter of weeks can make the difference. Patients should monitor their vision periodically and see their eyecare practitioner at the first sign of change, especially in one eye over the other.
Several companies manufacture and supply genetic testing kits. Generally, the testing is covered by medical insurance, as long as there is a diagnosis of AMD, using one of four specific ICD-9 codes.
The future is brighter for patients with AMD as well, thanks to several promising treatment methods. Because part of the immune system responsible for progression in AMD attacks cell membranes, inhibiting this significantly reduces new blood vessel growth in the retinas of mice. Studies are ongoing which have provided proof of concept for using genetic therapies in patients with advanced AMD.
There are some who will view all this with mixed feelings; because we can do something, does that always mean that we should do it? Of course not, but the advantages of knowing how much risk you may have for developing AMD will help you change your lifestyle, stop smoking and begin taking the correct vitamin and mineral supplements to help prevent its onset. Better monitoring with more frequent eye examinations will also help prevent vision loss from undiagnosed AMD.