There are two major forms of macular degeneration: atrophic (dry) and exudative (wet). 90% of all macular degeneration is the dry form, but 90% of all legal blindness from macular degeneration is due to wet macular degeneration.
It has been estimated that patients with dry macular degeneration have about a 1%-5% chance per year of converting from the dry form to the wet form. Once wet macular degeneration has happened in one eye, the chance of it happening in the other is increased.
Clinically this is characterized by yellow spots under the retina, called drusen, which are accumulations of metabolic waste products that indicate cells are not healthy. Areas of pigment clumping and atrophy (retinal thinning) are also found. Over time, large areas of thinning called geographic atrophy can cause severe visual loss.
Symptoms of dry macular degeneration include:
- Slow but progressive visual loss over the years
- Spots of blurred vision or distortion
Although this accounts for only 10% of macular degeneration, it is responsible for the majority of legal blindness from the disease. It is characterized by a rapid visual loss as abnormal blood vessels grow underneath the retina and leak fluid and bleed. Over time, these vessels have associated scar tissue which can lead to permanent scar formation under the retina.
Symptoms of wet macular degeneration include:
- Rapid visual loss as abnormal blood vessels grow underneath the retina and leak fluid and bleed.
Although we have treatments for macular degeneration, it must be understood that these do not cure the disease or reverse visual loss in many cases.
The goal of currently available treatments is to stop or reduce leakage and bleeding, and to minimize the size of the blind spot. However, outcomes are improving with newer medications. Many patients should at least stabilize with these treatments.
If macular degeneration is left untreated, the blind spot will continue to enlarge with the blood vessels continuing to leak fluid and occasionally bleed. Scarring and permanent damage generally occurs to some extent in most patients. Once scarring has occurred, no currently available treatment will be effective.
Treatment options include:
- Preventative care
- Anti-VEGF antibody drug therapy
- Photodynamic Therapy
- Triamcinolone Acetate (Kenalog)
- Low Vision Aids
- Preventative Care
- Anti-VEGF drug therapy
- Photodynamic Laser Therapy
- Triamcinolone Acetate (Kenalog)
- Low Vision Aids
There is no effective treatment for macular degeneration. Once this degeneration has occurred, visual loss in that area is permanent. However, there are preventative care steps that can be taken to slow the visual degeneration.
It is recommended that all macular degeneration patients:
- Stop smoking
- Wear sunglasses with ultraviolet protection
- Control hypertension
- Check vision daily with Amsler grid
- Take daily vitamins as recommended by doctor
Various antioxidants and vitamin supplements have been shown in studies to help lower the risk of developing advanced macular degeneration.
Current Vitamin Recommendations:
- For patients at risk for advanced macular degeneration, we recommend PreserVision with Lutein, 1 softgel twice a day with meals. (While there are many other supplements available, the AREDS formulation is the only one used in a well-designed, randomized, long-term, placebo-controlled trial).
- If you have a smoking history or currently smoke, we suggest PreserVision Lutein Gelcaps, 1 tablet twice a day to avoid the increased risk of lung cancer in smokers with high-dose beta carotene.
- If you cannot afford the full dose of an AREDS-based formula, the single most important ingredient to try to match is zinc. The Equate Vision Formula will give you the approximate AREDS-recommended doses of zinc at a reduced cost.
- Take Centrum Silver or another multivitamin
- Patients on coumadin (warfarin) should notify their primary care doctor, and have their PT/INR checked within 1 week of starting these supplements due to the high-dose of vitamin E
- We recommend a cautious approach with herbs and other supplementation. Unlike PreserVision, these have not been subjected to rigorous randomized, controlled clinical trials. In addition, there can be great variability in different preparations. As of now, current evidence suggests that;
- Ginko may slow damage
- Bilberry has little evidence of any help
- St. John’s wort may be harmful due to phototoxicity
The goal of currently available treatments is to stop or reduce leakage and bleeding, and to minimize the size of the blind spot. However, outcomes are improving with newer medications such as ranibizumab (Lucentis) and bevacizumab (Avastin). Many patients should at least stabilize with these treatments.
With the availability of two excellent anti-VEGF agents, a common question posed to physicians is which agent (Avastin or Lucentis) is “better.” Based on our experience, the drugs appear equivalent in terms of clinical response. Both have been extremely well-tolerated with no known systemic side effects, which is most likely attributable to the very low intraocular doses and route of administration. The biggest difference between the two agents is cost.
Bevacizumab is an anti-VEGF antibody that was originally approved by the FDA for treatment of colorectal cancer. Through pioneering work at the Bascom Palmer Eye institute in Miami, Dr. Phil Rosenfeld and colleagues have shown this to be a very effective treatment for exudative macular degeneration.
It is administered as a monthly intravitreal injection and is a quick and painless procedure that only requires topical and subconjunctival anesthesia. In our experience, results are very comparable to ranibizumab (see below). We have used this medication extensively in our clinic since 2005.
Ranibizumab is an anti-VEGF antibody fragment that was derived from bevacizumab with the hope of improving retinal penetration. Based on two randomized clinical trials (ANCHOR and MARINA), it was approved by the FDA for treatment of exudative (wet) macular degeneration and became available in 2006. Like bevacizumab, it is administered as a monthly intravitreal injection.
This laser treatment uses a light-sensitizing dye injected into a vein to more selectively destroy the vessels and spare the overlying retinal tissue. The dye, called verteporfin (Visudyne), is infused into the patient’s arm over a ten minute period. Five minutes later a laser is used to treat the vessels for 83 seconds. Because this photosensitizing dye is injected into a patient’s vein, the dye travels throughout their body and there are strict restrictions to avoid direct sunlight for five days.
Triamcinolone Acetate is a long-acting anti-inflammatory steroid which is used in wet macular degeneration for its action against blood vessel growth and retinal swelling. Two to four milligrams are injected through the white part of the eye directly into the vitreous cavity. The drug lasts in the eye for three months on average. Patients are followed-up on a monthly basis to monitor intraocular pressure which may rise after this injection. This typically works best in combination with other treatments.
A patient with macular degeneration generally requires more light and more magnification to be able to see. However, at certain levels of degeneration no amount of magnification will help. If you are interested in this, feel free to contact our office for assistance in locating a source close to you.
Visual aids include:
- Handheld magnifiers with or without lights
- Reading machines
- Closed circuit TVs
- Watches that speak
- Large button phones and playing cards with large symbols and numbers
- Other visual aids