Age-Related Macular Degeneration (AMD)
Gradual loss of central vision.
Painless
Incidious to rapid onset
AMD occurs in two forms: wet and dry.
Wet AMD – Begins as abnormal angiogenisis behind the retina under the macula. These new blood vessels are fragile and leak. Blood and serum elevate the macula and damage to the macula occurs rapidly.
With wet AMD, loss of central vision can occur quickly. Wet AMD represents advanced AMD.
Painless
Dry AMD 90% of cases. Represents atrophy of macular cells with a gradual onset of central blurring.
Painless.
Patients may complain about difficulty recognizing faces. Needing more light to read.
Dry AMD generally affects both eyes, but vision can be lost in one eye while the other eye seems unaffected.
Drusen are yellow amyloid deposits under the retina. An increase in the size or number of drusen forewarns progression to advanced dry AMD or wet AMD.
Dry AMD has three stages, all of which may occur in one or both eyes:
1. Early AMD. Patient has several small drusen. At this stage, there are no symptoms and no vision loss.
2. Intermediate AMD. Patient has increased drusen. Some people see a blurred spot in the center of their vision. More light may be needed for reading and other tasks.
Advanced Dry AMD. Drusen with extensive cellular break central retna. Blurred vision. Difficulty reading or recognizing faces. | ||
Notes
Almost all vision loss comes from advanced AMD, therefore, the wet form leads to significantly more vision loss than the dry form.
All people who have the wet form had the dry form first.
Dry AMD can advance and cause vision loss without turning into the wet form. The dry form also can suddenly turn into the wet form, even during early stage AMD. There is no way to tell if or when the dry form will turn into the wet form.
Both the wet form and the advanced dry form are considered advanced AMD.
Advanced AMD in one eye is a risk factor for developing advanced AMD in the other eye.
Risk Factors
Age >60
Smoking
Obesity/hyperlipidemia
Race Whites > African Americans.
Family history
Gender. Women > men.
HTN
Diabetes
AMD is detected during a comprehensive eye exam that includes:
1. Visual acuity test.
2. Dilated eye exam. After the exam, close-up vision may remain blurred for several hours.
3. Tonometry. An instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.
4. fluorescein angiogram for wet AMD
5. Optical coherence tomography used by most ophthalmologists for diagnosis and f/u evaluation of the response to anti-VEGF treatments.
Amsler grid. cover one eye and stare at a black dot in the center of the grid.
signs of AMD: straight lines appear wavy. some of the lines are missing. These may be
Amsler Grid
Treatment
Wet AMD
None of these treatments is a cure for wet AMD. The disease and loss of vision may progress despite treatment.
1. Laser surgery. destroy neogenic blood vessels. The risk of new blood vessels developing after laser treatment is high. Repeated treatments may be necessary. In some cases, vision loss may progress despite repeated treatments.
2. Photodynamic therapy with verteporfin. Systemic IV verteporfin. Adheres to endothelium. Medication is photoactivated by shining light in the eye. activated drug destroys neogenic blood vessels. Sparing normal tissue is an advantage over laser surgery. Because the drug is activated by light, you must avoid exposing your skin or eyes to direct sunlight or bright indoor light for five days after treatment.
Photodynamic therapy is relatively painless. It takes about 20 minutes and can be performed in a doctor's office.
Photodynamic therapy slows the rate of vision loss. It does not stop vision loss or restore vision in eyes already damaged by advanced AMD. Treatment results often are temporary. You may need to be treated again.
Photodynamic therapy is relatively painless. It takes about 20 minutes and can be performed in a doctor's office.
Photodynamic therapy slows the rate of vision loss. It does not stop vision loss or restore vision in eyes already damaged by advanced AMD. Treatment results often are temporary. You may need to be treated again.
3. anti-VEGF Injections. anti-Vascular Endothelial Growth Factor injected directly into the vitreous humor of the eye. The injections have to be repeated on a monthly or bi-monthly basis. can help slow down vision loss from AMD and in some cases improve sight.
bevacizumab (trade name Avastin, a close chemical relative of ranibizumab)
pegaptanib (trade name Macugen). $150 per treatment
When Dry AMD reaches the advanced stage, no form of treatment can prevent vision loss. However, treatment can delay and possibly prevent intermediate AMD from progressing to the advanced stage.
The National Eye Institute's Age-Related Eye Disease Study (AREDS): taking antioxidants and zinc significantly reduces the risk of advanced AMD.
Slowing AMD's progression from the intermediate stage to the advanced stage will save the vision of many people.
What is the dosage of the AREDS formulation?
500 mgs of vitamin C
500 mgs of vitamin C
400 International Units of vitamin E
15 mgs of beta-carotene (labeled as equivalent to 25,000 International Units of vitamin A)
80 mgs of zinc as zinc oxide
2 mgs of copper as cupric oxide.
Copper was added to the AREDS formulation containing zinc to prevent copper deficiency anemia, a condition associated with high levels of zinc intake.
Referral to low vision services. Will provide counseling, training and devices that may help you make the most of your remaining vision.
Indication for treatment
People who are at high risk for developing advanced AMD including:
1. Intermediate AMD in one or both eyes.
2. Advanced AMD (dry or wet) in one eye only.
The AREDS formulation is not a cure for AMD. It will not restore vision already lost from the disease. However, it may delay the onset of advanced AMD. It may help people who are at high risk for developing advanced AMD keep their vision.
Can people with early stage AMD take the AREDS formulation to help prevent the disease from progressing to the intermediate stage?
There is no apparent need for those diagnosed with early stage AMD to take the AREDS formulation. The study did not find that the formulation provided a benefit to those with early stage AMD. If you have early stage AMD, a comprehensive dilated eye exam every year can help determine if the disease is progressing. If early stage AMD progresses to the intermediate stage, discuss taking the formulation with your doctor.
There is no apparent need for those diagnosed with early stage AMD to take the AREDS formulation. The study did not find that the formulation provided a benefit to those with early stage AMD. If you have early stage AMD, a comprehensive dilated eye exam every year can help determine if the disease is progressing. If early stage AMD progresses to the intermediate stage, discuss taking the formulation with your doctor.
Dry AMD.
comprehensive dilated eye exam at once a year.
intermediate AMD in one or both eyes, or advanced AMD in one eye only, AREDS formulation
home check vision with Amsler grid
Wet AMD.
Treatment laser surgery or photodynamic therapy
f/u frequent eye exams to detect any recurrence of leaking blood vessels.
Stop smoking reduces recurrance
Home Amsler grid.
If you detect any changes, schedule an eye exam immediately.
don't be afraid to use your eyes for reading, watching TV, and other routine activities. Normal use of your eyes will not cause further damage to your vision.
Referral to low vision services. Will provide counseling, training and devices that may help you make the most of your remaining vision.
