In a previous Blog, http://blog.cnib.ca/archive/2011/12/15/age-related-macular-degeneration-amd.aspx, I mentioned and discussed at some length the two types of AMD – Dry AMD and Wet AMD. In this Blog I will be discussing how these diseases may be diagnosed and the treatments available for both of these forms of AMD. Before I do so I would like to mention yet again that this Blog is not intended to take the place of good medical advice. Since all medical situations are individual, it is important that you always consult your eye doctor regarding your eye condition.
Diagnosis of AMD:
The most important thing one can do for your eye health is to make sure you have a regular eye examination by an eye doctor. Many eye diseases, most notably AMD, have very few symptoms in their early stage, so that it is possible to have the disease without being aware of it. Your eye doctor can, however, often detect the disease through an eye examination, often involving special equipment. None of these tests will harm your vision. Some of the tests that an eye doctor will conduct to decide whether or not you have AMD include a visual acuity test (an eye chart); a dilated eye exam in which drops are placed in your eye that cause your pupil to dilate and thereby allows the eye doctor to see the back of your eye; fluorescein angiography - a test in which a dye is injected into your vein and allows the doctor to examine the blood vessels in the back of your eye; and Optical Coherence Tomography (OCT) an instrument that allows doctors to examine the retina in detail and decide whether there has been any damage consistent with AMD. Not all of these tests may be used on a routine eye examination.
There is a test that one can do at home that is fairly simple to do and can help to assess whether you have lost any vision due to AMD. It is called the Amsler Grid. It consists of a grid of horizontal and vertical lines with a black dot in the centre. One focuses on the black dot from a given distance and assesses whether any of the lines look distorted or wavy.
Treatment of AMD:
So what is your doctor going to do to treat you if you have AMD?
If you have Dry AMD:
At present there are no treatments for Dry AMD. However, a study conducted by the National Eye Institute in the United States, called the AREDS study, showed that a particular combination of vitamins and minerals decreased the risk of Dry AMD progressing from the intermediate stage of the disease to the advanced stage. This combination of vitamins and minerals is marketed under a number of brand names with an additional label that says: “AREDS formula”. While these vitamins/minerals are available in drug stores over the counter, it is important that you discuss their use with your eye doctor, before you start using them.
The AREDS formula is only effective in patients with intermediate to advanced Dry AMD. Only your eye doctor knows for sure whether they will be effective for you.
A second stage of this study (called AREDS 2) is currently underway in which the effect of additional supplementation to people taking the AREDS formula is being evaluated. The additional supplements being evaluated are two antioxidants, called Lutein and Zeaxanthin and two omega-3 fatty acids. At this stage it is not known whether supplementation with these antioxidants and omega-3 fatty acids is effective in dry AMD.
If you have Wet AMD:
The most commonly used treatment for wet AMD involves injections into the eye with a medication called anti-VEGF treatments. The only anti-VEGF treatment approved by Health Canada for use in patients with Wet AMD is called Lucentis, although, as mentioned in a previous blog, an anti-VEGF treatment called Avastin, previously approved for use in colorectal cancer, is being used by ophthalmologists to treat Wet AMD. Although Avastin has not been approved by Health Canada, ophthalmologists do have the discretion to be able to use un-approved medications for patients for whom they deem the drug necessary.
There are a number of treatments under investigation for use in Wet AMD. The closest to market appears to be another anti-VEGF treatment called VEGF Trap-Eye. At this stage it is too early to predict if and when this medication will be available in Canada.
Other treatments that are used infrequently for treating Wet AMD are: laser photocoagulation therapy in which a thermal laser is used to stop the growth of abnormal blood vessels; and photodynamic therapy in which a “cold” laser is used inside the eye to activate a drug that has been injected intravenously into the arm.
Anti-VEGF treatments have made a huge difference to the lives of many people with Wet AMD. They are the first treatments that can actually restore a significant amount of sight to a number of people with Wet AMD (not everyone), while preventing further deterioration of sight in an even larger proportion of patients with Wet AMD.
New treatments for AMD are constantly being discovered so it is important to consult regularly with your eye doctor to stay informed and see if any of the latest developments are good for you.
This Blog is not intended to take the place of good medical advice. Since all medical situations are individual, it is important that you always consult your eye doctor regarding your eye condition and your personal physician regarding your general health and any diet, exercise program or smoking cessation program you undertake.