Why am I losing vision despite treatment for age-related macular degeneration?
Age-related macular degeneration (ARMD) is the most common cause of visual loss in older Americans. Vision may be lost from dry-type or wet-type ARMD:
- Dry-type macular degeneration is the most common type and involves the disintegration of the light-sensitive tissues in the macula. Loss of vision is usually gradual in dry macular degeneration. Small blind spots interfere with reading numbers in a row and all the letters of a word. Over time, these blind spots usually enlarge and take away most of the central vision.
- Wet-type macular degeneration accounts for about 10% of all cases of ARMD. It occurs in patients with dry-type ARMD when abnormal blood vessels grow under the macula and cause fluid leakage, bleeding, and scarring of the macula. Vision loss may be rapid and severe. Straight lines may appear distorted and the central vision appears blurred early in wet-type ARMD. Over time, a large blind spot may develop in the center of the vision. If one eye develops wet ARMD, there is about a 50% chance the other eye will be affected within the next five years.
There is currently no proven drug treatment to stop dry-type ARMD. Eye vitamins are prescribed for dry-type ARMD. However, the main purpose of the vitamins is to stave off the start of wet-type ARMD. Although AREDS eye vitamins appear to slow the start of blind spots in the vision from dye-type AMD, they do not slow the progression of blind spots once they start. A Meditteranean diet appears to reduce the onset and progression of blind spots from dry-type macular degeneration. Therefore, it is important to limit red meat intake to once per week, eat two servings of whole fruit per day, include fish in the diet, and rely on olive oil rather than other oils with saturated fatty acids. There are a number of on-going research studies to find a treatment to slow or prevent loss of vision from dry-type ARMD. There is even hope for treatment to reverse the loss of vision from dry-type ARMD. Your doctor can put you in touch with study centers if you are interested in learning more about or participating in these research studies. Age-related macular degeneration appears to be an inherited condition. However, it may be aggravated by factors that cause hardening of the arteries like high blood pressure, high cholesterol, overweight, physical inactivity, and tobacco use. Efforts to control these factors may be helpful in slowing loss of vision in dry-type ARMD.
There are fairly good treatment options for wet-type ARMD. Injection therapy (Avastin, Lucentis, Eylea, and Beovu) is the first-line treatment for wet-type ARMD. Lasers are second-line treatment options. Lasers include photocoagulation (which is rarely used currently) and Visudyne photodynamic therapy. Treatment of wet-type ARMD is effective at slowing the loss of vision. Unfortunately, current treatments do not completely prevent the loss of vision from ARMD. There are several reasons why patients may continue to lose vision during treatment of ARMD:
1. Insufficient treatment
Some eyes require injection therapy every four weeks to optimal effect. If treatment is given less often, the wet-type ARMD may progress with loss of vision that may be irreversible. This is an important reason to continue monthly injections in some eyes (as determined by the retinal specialist).
2. Bleeding despite treatment
Bleeding under the retina from ARMD usually results in some degree of permanent scar tissue and loss of vision. Bleeding may occur if treatment is not given frequently enough and appears more likely in patients who take blood thinners. Blood thinners (including aspirin) are usually prescribed to prevent heart attack or stroke. If they are prescribed, the benefits likely outweigh the risks. However, if blood thinners are not prescribed for a patient with ARMD, they may be best avoided to reduce the risk of bleeding from ARMD.
3. Progression of dry-type ARMD while wet-type ARMD is being treated
Many patients are not aware that ARMD always starts with the dry-type. Wet-type ARMD develops later. Therefore, patients with wet-type ARMD may lose vision over time even though their wet-type ARMD is well controlled. That in, they may lose vision from a worsening of dry-type ARMD over time. Complicating this issue is the concern that the very treatment of wet-type ARMD may, in some cases, worsen the dry-type ARMD.
4. New eye problems develop during treatment of ARMD
The ophthalmologist will look for other problems that may cause a loss of vision unrelated to ARMD. Common causes of vision loss include cataract, which is treatable with surgery. Other problems include glaucoma, retinal vein occlusion, and diabetic retinopathy.
What is to be done about the continued loss of vision?
There are a number of actions that may be taken in response to continued loss of vision during treatment of ARMD. The retinal specialist will look for other causes of loss of vision and start appropriate treatment. The frequency of treatment may be changed in response to changes in the retina. Low vision aids (optical and electronic magnifiers) may be helpful. Specially-trained social workers may help make changes in the household to make it easier to remain self-sufficient. It is helpful to remember that the peripheral vision is rarely taken by ARMD. Therefore, although a patient may be determined to be legally blind, total blindness is rare. Most patients with advanced ARMD are able to ambulate and retain independence.
For a telemedicine consultation with Dr Pautler, please send email request to spautler@rvaf.com. We accept Medicare and most insurances in Florida. Please include contact information (including phone number) in the email. We are unable to provide consultation for those living outside the state of Florida with the exception of limited one-time consultations with residents of the following states: Alabama, Arkansas, Connecticut, Georgia, Minnesota, and Washington.
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