If you are experiencing warning signs of age-related macular degeneration or would like more information on this disease, please contact the Progressive Vision Institute at any of our locations.
What is Macular Degeneration?
In order to understand Macular Degeneration, it is first necessary to understand the basic anatomy of the eye. The “Macula” is the central area of the retina. It is responsible for reading vision and fine visual tasks. Macular degeneration attacks this center part of the eye. It destroys central vision, which is necessary for reading, driving, identifying faces, watching television, and doing fine detailed work. In its earliest stages, age-related macular degeneration (AMD) can be difficult to detect. Sometimes it progresses so slowly that people do not notice a change in their vision, and years may go by before they see an ophthalmologist or eye care professional. In other cases, the deterioration can be very rapid and can appear to happen overnight.
Early diagnosis of AMD is essential to successful treatment. Age-related macular degeneration, as the name implies, affects the macula, which is about the size of the “O” in this sentence. The macula is the part of the retina which is responsible for our most detailed vision. We use the macula for reading, driving, recognizing faces, watching television, and fine work. The root causes of macular degeneration are still unknown.
Forms of AMD
There are two forms of Age Related Macular Degeneration: “wet” and “dry”.
- Dry Macular Degeneration: This is the more common type of AMD. In the dry form, there is thinning of the retinal pigment epithelial cells (RPE). These RPE cells are important to the health of the retina. The degeneration of these cells causes destruction of the overlying photoreceptors. Dry Macular Degeneration reduces one’s central vision and can affect color perception. Generally, the damage caused by the “dry” form is not as
severe as that of the “wet” form.
- Wet Macular Degeneration: This is the more severe type of AMD. It accounts for ninety percent of the blindness caused by this disease. As we age, new abnormal blood vessels grow between the retina and its underlying carpet of blood vessels. These new abnormal blood vessels tend to be very fragile. They often grow, leak or bleed, scarring the macula. This damage to the macula results in distortion and rapid loss of central vision. The “wet” form accounts for ninety percent of all cases of legal blindness in macular degeneration patients.
Different forms of macular degeneration may occur in younger patients. These non-age related cases may be linked to heredity, diabetes, nutritional deficits, head injury, infection, or other factors.
Warning Signs of Age-Related Macular Degeneration
Declining vision noticed by the patient or by an ophthalmologist during a routine eye exam may be the first indicator of macular degeneration. The formation of new blood vessels and exudates, or “drusen,” from blood vessels in and under the macular is often the first physical sign that macular degeneration may develop. In addition, the following signs may be indicative of macular problems. Anyone experiencing these symptoms should consult an ophthalmologist immediately:
1. Straight lines appear distorted and in some cases, the center of vision appears more distorted than the rest of the scene.
2. A dark, blurry area or “white-out” appears in the center of vision.
3. Color perception changes or diminishes.
Treatments of Age-related Macular Degeneration:
The “good” news about macular degeneration is that there are many new treatments, which will allow more and more people to continue to enjoy many of their favorite activities and lead normal, independent lives. Under the expertise of our board certified fellowship trained retinal specialists Drs. Shann Lin, Melissa Neuwelt, and Caesar Luo, these treatments are now available at the Progressive Vision Institute at all of our locations.
- Conventional direct laser photocoagulation: In this treatment, direct lasers are used to ablate the whole area of new blood vessel growth. A consequence of the laser treatment is the destruction of the overlying retina. Therefore, this approach can only restore vision in those cases where the new blood vessel growth is not yet under the center of the macula. Unfortunately, a vast majority of patients have these new blood vessels underneath the center of the macula at the time of diagnosis.
- Feeder Vessel treatment: Scientific studies (Transactions of the American Ophthalmologic Society. 1977; 75:180-254) show that these abnormal blood vessels are supplied by one or a few tiny individual feeder vessels. Until recent advances in the detection of feeder vessels, only occasional reports of successful treatment of these feeder vessels appeared in the scientific literature. Dr. Lin is one of the pioneers in developing this new treatment. With the advent of new high-speed scanning laser imaging systems and infrared laser systems, success rates of detecting and stopping the flow to these feeder vessels have improved. Feeder vessels are identified using high-speed scanning laser ICG videoangiography. Feeder vessels were identified in more than 80% of patients studied. In a pilot study, 78% of patients treated have reported stable or improved vision at a 6-month follow-up.
- Intravitreal injections: This is the most common and effective mode of therapy for wet macular degeneration at this time. Vascular endothelial growth factor (VEGF) is known to be abnormally elevated in eyes with macular degeneration, and medications were utilized to target VEGF. Ranibizumab, or Lucentis, was approved for use in the eye in 2006, and has been utilized with great success in a previously blinding disease. In the landmark MARINA and ANCHOR trials, patients treated with Lucentis showed a 90% stabilization rate in macular degeneration, while 50% of patients showed an improvement, and over 30% of patients showed a drastic improvement in their vision. Since that time, several other anti-VEGF medications have been used, including bevacizumab (Avastin) and aflibercept (Eylea). Currently in late phase trials is a treatment (lampalizumab)for geographic atrophy, an advanced form of macular degeneration that currently has no treatment. Lampalizumab will also be injected directly into the eye.
- Photodynamic Treatment: Photodynamic therapy (PDT) utilizes light-activated drugs to treat the abnormal new blood vessel. Treatment with photodynamic therapy consists of a two-step process beginning with administration of the drug by intravenous injection. The drug is then “activated” with a pre-calculated dose of light at a specific wavelength. The activated drug subsequently causes cell death by disrupting normal cellular functions. Because the light is shone directly at the targeted tissue and the drug accumulates preferentially in these cells, photodynamic therapy can result in a highly selective treatment. Selectivity is advantageous because it reduces damage to the retina and its photoreceptors. Dr. Lin has been performing photodynamic treatment since 1998 as a clinical investigator. Photodynamic treatment was approved in April 2000 for treatment of macular degeneration by the Food and Drug Administration.
- Transpupillary thermotherapy: Transpupillary Thermotherapy (TTT) is a method of delivering low-grade heat to the back of the patient’s eye using a diode laser. This creates a localized hyperthermia, which results in the closure of abnormal new blood vessels. TTT results in temperature elevation of the target tissue, typically about 5 degrees Celsius to 7 degrees Celsius, which is well below the coagulative threshold. Therefore, damage to the retina is minimized.
- Pneumatic displacement of subfoveal hemorrhage: The fluid and blood that accumulates under the retina during Macular Degeneration results in a localized retinal detachment. By performing vitrectomy, an infusion of a bubble of air or a special gas into the vitreous cavity of the eye, blood and fluids can be pushed away from the center of the eye. Recent studies have shown that this technique can effectively treat sufferers of Wet Macular Degeneration with blood under the macula who are not eligible for laser treatment. In these cases, laser is sometimes needed after the fluid and blood are displaced from the macular region by the bubble.
- Nutrition: The Age Related Eye Disease Study (AREDS) was a landmark trial by the National Eye Institute which showed a 25% reduction in the risk to progression from dry to wet macular degeneration with supplementation by a specific vitamin and mineral formula. This formula consisted of vitamins A, C, E, zinc and copper. This was recently supported by the AREDS2 trial, which examined the benefit of adding lutein, zeaxanthin, and omega 3 fatty acids. Vitamin A has been shown to increase the risk of lung cancer in patients who are current or past smokers. The AREDS2 trial showed a similar reduction of risk even by replacing the Vitamin A with lutein and zeaxanthin. Omega 3 was not shown to be of any benefit. At this time, the our vitreoretinal specialists would recommend any patient with moderate to advanced dry macular degeneration to initiate supplementation with the AREDS2 formula, consisting of lutein, zeaxanthin, vitamin C, vitamin E, zinc, and copper.
Early Detection and Treatment
Early detection is important because a patient destined to develop macular degeneration can sometimes be treated before serious symptoms appear, and this may delay or reduce the severity of the disease. If you are experiencing warning signs of age-related macular degeneration or would like more information on this disease, please contact the Progressive Vision Institute at any of our locations.