Macular degeneration treatment options
Once AMD has been diagnosed, it is important to commence appropriate management immediately. This is usually directed by an ophthalmologist (eye specialist), but can be supported by your optometrist.
As previously noted, [insert link to previous post], dry AMD is the more common of the two AMD subtypes and it is characterised by retinal drusen, pigmentation, and atrophy. Neovascular AMD (wet AMD) is less common but is imminently vision-threatening. Wet AMD presents with retinal fluid leakage and bleeding.
Treatment for Dry AMD
Currently, there are no prescription medications or surgery that can stop or reverse dry macular degeneration. However, there is some evidence that vitamin supplementation can slow down progression of dry AMD in certain subgroups of patients.
For most people, taking vitamins supplements isn’t necessary for eye health. Even though certain vitamin deficiencies can cause eye disease, these deficiencies are very rare in individuals with normal digestive function. Most healthy people get all the nutrients that their eyes need through a normal diet.
However, patients who have been diagnosed with AMD often ask their ophthalmologist if they should take vitamin supplements. The appropriate answer depends upon the severity of their AMD. For patients with very mild dry AMD, taking supplements does not appear to be of benefit, whereas supplements can help those with more established forms of AMD. Stopping smoking is also critically important.
Vitamins and supplements
The underlying pathophysiology of AMD is complex and involves the interplay of multiple factors. The role of oxidative stress as an element of the cascade underpins the rationale behind vitamin and antioxidant supplementation.
Some studies were undertaken in the United States of America, which examined this exact problem: can vitamin supplements slow down the progression of the disease, and, if so, which would be most effective? These studies were called the Age-related Eye Disease Studies (AREDS). Two series of AREDS were undertaken: in 2001 and 2006.
These were randomised controlled trials that investigated a concoction of vitamins and antioxidants to slow the progression of AMD (7-9) in people with intermediate or advanced AMD. They found that those who took specific supplement combinations reduced their risk of AMD progression by 10 to 25%.
AREDS1 categorized a large number of AMD patients according to their disease severity at baseline and then randomized them to receive either vitamin supplements or placebo.
This trial found that a combination of daily zinc 80mg, copper 2mg, vitamin C 500mg, vitamin E 400IU, and b-carotene 15mg reduced the progression to advanced AMD in select populations.
In the second AREDS trial (AREDS2), the formula was changed slightly. Zinc was reduced to 25mg and b-carotene was replaced with lutein 10mg and zeaxanthin 2mg. Zinc was reduced due to the risk of Zinc induced anaemia, and b-carotene was omitted due to an increased risk of lung cancer in smokers.
Baseline characteristics of AREDS patients
It is important to recognize the baseline characteristics of the patients in AREDS in order to determine whether its benefits are applicable to practice. In the AREDS1 and AREDS2 population, the majority of participants were Caucasian and concurrently took multivitamins (Centrum) throughout the study.
In the AREDS2 population, the effects of additional supplementation were minimized as participants ceased any supplements which contained any components of the AREDS2 formulation.
The following patients were excluded from the AREDS trials: patients outside the ages of 55 to 80 years, those with significant co-morbid ocular or systemic disease, previous ocular surgery other than cataract extraction, consumption of medications with ocular toxicity, prior prolonged use of lutein/zeaxanthin/omega-3 fatty acids, intraocular pressure >26mmHg, cataract surgery within 3 months, or YAG laser capsulotomy within six weeks. These exclusions should be kept in mind in determining whether supplementation with the AREDS2 formulation is likely to benefit a specific patient.
The results showed that only individuals in Category 3 or 4 (Table 2) who were randomized to receive vitamin supplements experienced a significantly reduced progression to advanced AMD (central GA or neovascular AMD) (11).
When Category 3 and 4 were grouped together, these patients experienced a 25% relative risk reduction in progression to advanced AMD at 7 years. The absolute risk reduction was 8%, meaning that 12 patients in Category 3 or 4 would need to be treated with vitamin supplements for 7 years in order to expect one to be spared from progression to advanced AMD (number needed to treat = 12).
Interestingly, supplements reduced the risk of neovascular AMD (OR 0.66) but did not reduce the risk of central geographic atrophy (OR 1.02) (12).
Individuals with only small drusen or less than 20 medium drusen did not experience a significant benefit from vitamin supplements.
AREDS2 optimized the supplement ingredients, but this study did not have a placebo arm, therefore it is difficult to know how the improvements to the supplement could expand the patient group that derives benefit.