Definition of Macular Degeneration

A definition of macular degeneration that you can understand!

Age-related Macular Degeneration, or AMD, is a very complex eye condition or disease, but with early detection and proper treatments, it is possible to reduce its severity and delay its progress.

What is AMD?

A simple definition of macular degeneration (AMD) is that it is an eye disease that affects the macula, the part of the retina that is responsible for central vision and the perception of fine detail. Central vision helps you see objects clearly and sharply, and is important for activities such as reading or driving. Although AMD may result in partial vision loss, it usually does not cause total blindness since it primarily affects your ability to see straight ahead, leaving your peripheral vision intact.

AMD is generally associated with age. It most commonly occurs in individuals over the age of 50, and is currently the leading cause of central vision loss among those 65 years of age and older in developed countries. The incidence of this disease is slightly higher in females than males.

AMD is a bilateral condition, meaning that it can affect both eyes, although the severity and progress may be different in one eye than the other.

Unfortunately, the cause of AMD is still unknown, although extensive research continues, with new methods and treatments being discovered to help slow the progress of symptoms.

A Definition of Macular Degeneration Types

Dry Macular Degeneration. This type of AMD occurs when the light sensitive cells in the macula breakdown, causing blurry spots and a gradual loss of central vision. Dry AMD progresses through 3 stages, and if caught early, it may be possible to slow the progression of these stages. Dry AMD accounts for more than 80% of AMD cases.

Wet Macular Degeneration. This type occurs when abnormal blood vessels begin to grow under the macula. These blood vessels are very fragile and rupture easily, causing blood and fluid to leak into the macula, resulting in severe damage and scar tissue. In medical terms, this is referred to as choroidal neovascularization, and usually leads to rapid vision loss.

Diagnosis, Detection and Signs of Macular Degeneration

AMD often results in blurry or distorted vision as well as a disruption in color perception, sometimes leading to color blindness. However, this disease can be present long before you begin experiencing any symptoms, so it is important to have the health of your eyes checked regularly by a professional.

AMD is usually characterized by the presence of specific conditions that will be recognized by your eye doctor:

• Drusen Formation: Drusens are white or yellow deposits of lipids (fatty substances) and calcium that develop under the retina or build up in the back of the eye. Drusens are very common and most people over the age of 30 have at least one. However, as these drusens accumulate waste products, they increase in size and number, increasing the risk of developing advanced dry AMD or even wet AMD.

  Drusens are identified as either hard or soft, with the hard ones being clinically insignificant and harmless. Soft drusens are usually early indicators of macular degeneration and often evolve into the disease.

• Atrophy of Photoreceptors. Everyone has specialized cells in the retina that respond to light and protect the eye. These cells are called photoreceptors, and one of their functions is to prevent excessive light from entering the eye and causing damage to the retina. The growth of drusens cause these photoreceptors to breakdown or die, leading to vision loss.

• Retinal Pigment Epithelial (RPE). This is a medical term for the layer of cells located directly behind the photoreceptors. The purpose of these cells is to nourish the eye, particularly the retina. As drusens develop, they effect the blood supply to the retina, depriving the RPE and the photoreceptors of oxygen and nutrients. In this case, the eye is unable to function properly and vision loss results.

• Neovascular Formation. Your eye doctor will be able to identify AMD by noticing the growth or formation of abnormal blood vessels under the macula. These vessels can break or leak, resulting in scar tissue and loss of vision.

Now that you have a definition of macular degeneration - take a look at the other articles in this series to further help you understand this issue and how to deal with it.

Our article series goes into greater detail, but you may find this video from Youtube - whilst narrated by a young girl - provides a good definition of macular degeneration and and its impact on people.

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