Age related Macular degeneration (AMD) is a leading cause of vision loss. It is a major health issue as our population ages and is eager to maintain independence. Preserving central vision allows us to drive and read our mail. Macular degeneration is referred to as dry or wet based on your physicians clinical findings.
Dry macular degeneration is characterized by a progressive thinning and atrophy of the macular region that results in poor central vision. Patients often describe a slow decline of vision with complaints of worsening contrast vision and the need for better lighting. You can think of it as “thread bare “ areas near the central vision that slowly expand leading to larger zones where there is no retina to receive the focused image. This only involves the central retina, or macula, and patients maintain peripheral vision. There is no bleeding or leakage of fluid into the retina.
Wet Age-Related Macular Degeneration
Wet age related macular degeneration, however, does involve bleeding and leakage of fluid into the central retina. This may occur relatively sudden and seemingly without warning. Common symptoms can include: sudden distortion of images or straight lines, a central gray or dark area, or just blurred vision. Early symptoms can be missed as we rarely check each eye individually and one eye may have problems while the other eye allows normal function. The bleeding and leakage of fluid associated with wet macular degeneration is the result of abnormal new vessels growing in the macular region. These new vessels tend to be fragile and may break and bleed without any action on your part.
As we age and become at risk for vascular events, prophylactic aspirin (ASA) has almost become a standard of care. This attempt to prevent clotting and its associated morbidities are obviously at odds with the goals of our wet macular degeneration patients. Many studies have looked at the association between ASA and wet AMDwith respect to causation and prognosis. It is a complex question as vascular disease is more common in patients with macular degeneration and smoking is an independent risk factor for both conditions.
In January 2012 The European Eye (EUREYE) Study reported on the association of ASA and AMD, as determined by questionnaire, within a group of 4700 patients. There was a variable use of ASA and of AMD severity among the participants and they showed that “frequent aspirin use was associated with early and wet late AMD” and the odds were greater with increasing frequency of ASA use. This cross sectional study did not determine causation but only says there may be a link. Obviously, each patients use of ASA or any other supplement must be evaluated on an individual basis but a practical assessment would be that prevention of stroke or heart attack with ASA use will outweigh any concern of ASA causing macular degeneration. The benefit of a healthy diet in green leafy vegetables and smoking cessation far outweigh any concerns associated with aspirin use.
For those patients with newly diagnosed wet AMD and active bleeding, it is reasonable to discuss a change in anticoagulant therapy for the short term. Drugs like Plavix, Coumadin, Pradaxa, and aspirin can exacerbate the bleeding with wet AMD in the short term. Fortunately, the new injection therapies cause regression of the offending new vessels and thereby dramatically reduce the risk of bleeding after a few injections.
Another common association and concern is whether a cataract eye operations cause macular degeneration to advance. There are over 3,000,000 cataract surgeries performed each year in the U.S. and many studies have explored this relationship. In November 2009, The Age-Related Eye Disease Study Report No. 27 reviewed 1939 eyes that had cataract surgery while enrolled in the national trial that evaluated antioxidants and minerals in macular degeneration. Each group showed a gain in vision but there was a declining benefit with more advanced pre-existing AMD. The benefit ranged from a gain of more than 8 letters in the group without AMD to only 2 letters gained in the advance AMD group.
In November 2012 the Australian Cataract Surgery and Age-related Macular Degeneration (CSAMD) study reported on the possible association between cataract surgery and the progression of AMD. This study used a fellow eye comparison so that it only included patients who had cataract surgery in one eye and left the other cataract alone for two years. Cataract operations were performed in 1851 patients and 71% had 36 months of follow up. The study showed no increased risk of early AMD or late AMD. There was a slight increase in retinal pigmentary changes in the operated group but the significance is yet to be determined.
Macular degeneration is a complex disease with many contributing factors including genetics, diet, smoking, and exercise patterns. Each study sheds a little more light on the subject but often leaves us with more questions. We believe it is safe to conclude the following:
- A diet that contains green leafy vegetables and fresh fruits is recommended. Vitamin supplementation with an AREDS approved vitamin is advised for patients with intermediate or advanced macular degeneration in one eye.
- It is reasonable to use aspirin on a daily basis but the patient’s eye care specialist should be aware of use of any anticoagulants for other medical conditions.
- Cataract surgery is safe in patients with macular degeneration but it is reasonable to evaluate with a retinal scan or have a retinal consultation before surgery if there is any doubt about the role of AMD in a patient’s vision loss.
- Tobacco cessation is necessary and cessation counseling should be provided.