When you go to the eye doctor, most doctors ask about a family history of 3 major things—glaucoma, retinal detachment, and macular degeneration.
What exactly is macular degeneration though, and why is it important?
Before we dig into the disease process of macular degeneration, it may be helpful to know what the macula is.
The backmost structure of the eye—the retina—is debatably the most important part of the eye as it contains a special layer of cells called photoreceptors.
Photoreceptors are light detecting cells. They are stimulated by light, and then send signals to the brain for image processing. Cumulation of all of the information from the millions of photoreceptors across the retina, therefore, are what are responsible for image creation.
Within the retina, there is a small area highly concentrated with photoreceptors called the macula.
This region of the retina is responsible for your central vision. It allows for your greatest visual acuity and for fine details.
The macula is essentially the “MVP” of the retina. The entire retinal anatomy is based around the macula, so keeping it clear and healthy is a vital part of good vision.
What is Macular Degeneration?
Macular degeneration is a disease in which the macula breaks down, or degenerates.
It occurs when lipids, cholesterol, and metabolic wastes deposit themselves beneath the macula at the layer called Bruch’s Membrane.
Bruch’s membrane is the outermost layer of the sub-retinal space called the choroid. The choroid is filled with blood vessels that provide nutrition to the retina.
The retina’s outermost layer is called the RPE (retinal pigmented epithelium). It is a very selective layer that allows nutrients from the blood to enter the retina for energy.
The RPE and Bruch’s membrane border one another. Thus, while the wanted nutrients enter the retina, all of the unwanted things like wastes, lipids, and cholesterol accumulate along Bruch’s membrane.
Typically, the body can reabsorb these wastes and no major problems ensue. However, in macular degeneration, wastes accumulate along Bruch’s membrane and interfere with the ability of the retina to absorb nutrients.
The cumulation of lipids, cholesterol, and waste form yellowish colored deposits called drusen.
A little drusen here and there is normal and is even expected with aging. However, excessive amounts of lipid deposition can be detrimental to the health of the macula.
When many drusen accumulate, it cuts off the macula’s supply to nutrients such as oxygen, and the macula will begin to die off (degenerate).
Once the photoreceptors of the macula die, they cannot regenerate. Therefore, an individual will begin to lose splotches of their central vision that can coalesce to essentially black out the entirety of the person’s central vision.
Types of Macular Degeneration
There are two types of macular degeneration—dry and wet.
Dry macular degeneration is the more frequently encountered type of macular degeneration.
It occurs as outlined above with significant accumulation of drusen beneath the macula, resulting in slow macular death.
Wet macular degeneration, on the other hand, is a more advanced form of macular degeneration.
It occurs when the accumulation of drusen and blood put so much pressure on Bruch’s membrane that it rips and blood and serous fluid leak into the space between the RPE and Bruch’s.
Little pockets of blood and fluid between the RPE and Bruch’s membrane is called a choroidal neovascular membrane, and is exactly what we want to prevent from happening.
Pockets of fluid lead to new blood vessel growth into the retina, interfering with the structural integrity of the retina and causing further vision loss, as these new blood vessels tend to be of poor quality and leak blood into places it should not.
Thus, a more simplistic way to differentiate between dry and wet macular degermation is wet macular degeneration has the presence of blood in the retina, whereas dry is just drusen accumulating along Bruch’s membrane.
A person with dry macular degeneration can advance to wet macular degeneration, as dry macular degeneration always supersedes wet macular degeneration.
Why Does Macular Degeneration Occur?
The exact mechanism of macular degeneration is unknown. We know lipids and wastes accumulate on Bruch’s membrane, but why exactly this occurs more significantly in some rather than others is unknown at this time.
Unfortunately, the greatest risk factor for macular degeneration is age. You may also hear macular degeneration referred to as “age-related macular degeneration” or ARMD for short.
Genetics also play a role in macular degeneration. If a relative has macular degeneration, it is of upmost importance that you stay diligent with your annual eye exams to watch for any early signs of macular degeneration in yourself.
However, it is important to note that just because a family member has macular degeneration does not necessarily mean you will get it at as well. There are many other risks associated with the disease that can cause it to occur in some and not others.
The second greatest risk factor for macular degeneration is smoking. This includes cigarette, cigar, and electronic cigarette (vape) smoking. Avoiding smoking is one of the best ways to prevent macular degeneration from occurring!
Other risks associated with development of macular degeneration include obesity and diets high in fats and cholesterols, excessive UV exposure, and myopia (near sightedness).
Treatment for Macular Degeneration
When it comes to a diagnosis of dry macular degeneration, there is not a lot that can be done.
Studies have shown that in moderate/advanced stages of the disease, special eye vitamins may help in preventing the disease from further progression.
These vitamins are called the AREDS 2 formula, and contain vitamins Lutein and Zeaxanthin, among others.
Lutein and Zeaxanthin are antioxidants, which help to remove wastes in the body. It is hypothesized that these antioxidants help to remove some of the wastes that accumulate on Bruch’s membrane.
Other treatments for dry macular degeneration include healthy diet, exercise, and cessation of smoking.
The good news is, most cases of dry macular degeneration stay in the mild stage, which rarely have a major impact on vision.
The ultimate goal of treatment of dry macular degeneration is to keep it from progressing further into wet macular degeneration.
For wet macular degeneration, treatment focuses on promoting the body to reabsorb the blood leaking into the retina and prevent further growth of new blood vessels.
This is accomplished through a series of eye injections containing anti-VEGF, or laser surgeries which essentially burn the new blood vessels so that they cannot continue to grow. Both of these have their own risks and side effects, however, and vision likely will never return back to the 20/20 it once was.
Whatever the case, your doctor will work with you to find the best treatment applicable. If vision loss has occurred, there are many devices available to help rehabilitate you to normal life. No matter which type of the disease you have—dry or wet—we are here to help!