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Age-related Macular Degeneration
Summary
What Is It?
Macula is the center part of the retina, like the bull’s eye, on a dart board. It allows you to see details and center part of your sight. Over time, these cells become damaged which is called age-related macular degeneration (AMD). Initially, all patients with macular degeneration start with dry AMD which means that there is no bleeding. However, as the damage progresses, 10% of the patients can develop bleeding in the macula which is called wet AMD. AMD is the leading cause of vision loss in the US.
Analogy
Imagine a forest drying up over time from lack of water and overuse. You can lose the forest gradually leading to barren patches of soil, or the dry patches can catch on fire leading to destruction of the forest. In the same way, the cells in the retina can become damaged leading to erosion and forest fire.
If the erosion involves the macula, then your center and detail vision can be lost depending on the extent of the damage. This is the equivalent to dry macular degeneration which is called geographic atrophy when it is significant and causes decreased center and detailed vision.
If the damage progresses beyond a certain threshold, then the damaged cells cause a certain sequence of reactions causing new vessels to be formed (angoiogenesis, neovascularization). This is similar to the dried trees causing a forest fire. Although it sounds like a good idea, the new vessels are weak and they will break and bleed. This is the called wet macular degeneration
How Does Impact My Life?
Early on, it may not cause any damage. As the condition progresses, it may cause:
- straight lines to become wavy
- missing patches of vision in the center
- decreased ability to make out details both at distance and at near
- in the end-stage, as you look at a person’s face, the person’s face may be missing but the periphery remains intact
What Causes It?
Main causes are
- aging
- genetics
- smoking
Other causes include
- high blood pressure
- high cholesterol
- sun exposure
- light skin and iris
- poor diet
How Do You Treat It?
Dry AMD
AREDS 2 stands for Age-Related Eye Study 2. which was large study carried out by the National Eye Institute that showed that a certain combination of vitamins and minerals helped to slow the progression to advanced macular AMD by up to 25%. It is currently considered to be the standard care. Please consult your primary care doctor prior to taking it.
AREDS 2 formula
- Vitamin C (500 mg)
- Vitamin E (400 IU)
- Lutein (10 mg)
- Zeaxanthin (2 mg)
- Zinc (80 mg)
- Copper (2 mg)
Wet AMD
Wet AMD is caused by damaged cells producing chemicals that lead to formation of new blood vessels. This main chemical is called VEGF (vascular endothelial growth factors) which promote growth of new but fragile blood vessels. Treatments are aimed at preventing these molecules from performing their actions and are performed through a series of injections into the eye.
The main medications that are available for injection are
- Avastin (Bevacizumab)
- Lucentis (Ranibizumab)
- Eylea (Aflibercept)
- Vabysmo (Faricimb-svoa)
- Susvimo (Ranibizumb)
Treatment Course
The injections are initially performed on a monthly basis. Once the bleeding has been stabilized and resolved, the injections are sometimes tapered gradually as tolerated by the condition or continued on a monthly basis. Due to the difference between patients, there is no single correct treatment protocol and the decision to choose the correct protocol is often made after a discussion with the patient.
Resources
American Academy of Ophthalmology Eye Health website provides updated information on eye diseases
American Society of Retinal Surgeons provides overview of macular degeneration