Macular Degeneration

Adult and Juvenile

Summer 2014Brandey Burnett, Amanda Noles, Jamie Points

What is Macular Degeneration?

Macular Degeneration is a common, painless eye condition in which the central portion of the retina (a light-sensitive

layer of tissue, lining the inner surface of the eye) deteriorates and does not function adequately.

Types of Macular Degeneration

There are many types of macular degeneration.

• Age-related macular degeneration (AMD) is by far the most common type. AMD occurs as part of the body’s natural aging process

• Another type is Juvenile Macular Degeneration (JMD). Juvenile macular degeneration is different from AMD and is sometimes called macular dystrophy.

As macular degeneration develops, clear, normal vision ( left) becomes impaired by a general haziness. With advanced macular degeneration, a blind spot forms at the center of the visual field (right).

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What is Age-related Macular Degeneration?

Age-related macular degeneration (AMD) is the leading cause of vision loss in Americans 60 years of age or older. It progressively destroys the macula (the central portion of the retina) impairing the central vision. It affects the sharp central vision that is needed for seeing objects clearly. It is difficult or impossible to complete common every day tasks such as reading, recognizing faces, and driving, however, enough peripheral vision remains to allow other activities in daily life. It rarely causes blindness because only the center of vision is affected. The use of magnifying devices can often improve vision in macular degeneration to allow for reading or watching television.

Two Forms of Age-related Macular Degeneration

AMD occurs in two forms: • “Dry” age-related macular degeneration is the more common type and is

more slowly progressive in causing vision loss. • "Wet" age-related macular degeneration is less common but more

aggressive in its progression to severe central vision loss.

All people who have the dry form of AMD are at risk for development of the wet form. Therefore, people who have the wet form had the dry form first. Currently, there is no certain way to predict if or when the dry form will turn into the wet form.

Dry AMD can advance and cause vision loss without turning into wet AMD. Dry AMD can also rapidly transform into the wet form by the growth of new blood vessels.

What is “dry” Age-related Macular Degeneration?

In dry AMD, the light-sensitive cells and supporting tissue in the central retinal area slowly break down, causing central vision to diminish over time. This breakdown can cause a blurred spot in the center of vision. Eventually, the blurred spot may get bigger and darker, taking more of the central vision.. Early stages of dry AMD can be treated with high-dose formulations of antioxidants and zinc, which may delay and possibly prevent AMD from progressing to a more advanced stage. Once in the advanced stage, no form of treatment can restore vision loss.

Early symptoms of dry AMD include slightly blurred vision, the need for more light for reading and difficulty recognizing faces until very close to the person. A symptom of more advanced dry AMD is the presence of a blurred spot in the center of vision.

Treatment for Dry Macular Degeneration

There is currently no treatment available to reverse dry macular degeneration. However, dry macular degeneration is usually slowly progressive and most patients with this condition are able to live relatively normal, productive lives. Often one eye is affected more than the other.

Once dry AMD reaches the advanced stage, no form of treatment can prevent further vision loss. However, treatment can delay and possibly prevent intermediate AMD from progressing to the advanced stage of severe vision loss. The National Eye Institute's Age-Related Eye Disease Study found that taking a specific high-dose formulation of antioxidants and zinc significantly reduces the risk of advanced AMD. Slowing AMD's progression from the intermediate stage to the advanced stage is helpful in reducing the progression of visual loss in many people.

What is “wet” Age-related Macular Degeneration?

In wet AMD, abnormal blood vessels behind the retina start to grow under the macula and leak blood and fluid, causing loss of central vision, which may occur quickly. Treatment includes laser surgery, photodynamic therapy, and injections in to the eye. None of these will cure the disease and loss of vision may still progress.

An early symptom of wet AMD is the wavy appearance of straight lines. During an eye exam, you may be asked to look at a checkerboard pattern called an Amsler grid. When looking at an Amsler grid with one eye, patients with AMD may notice that the straight lines of the checkerboard appear wavy or are missing.

Treatment for Wet Macular Degeneration

Wet AMD can be treated with laser surgery, photodynamic therapy, and injections into the eye. None of these treatments is a permanent cure for wet AMD. The disease and loss of vision may progress despite treatment.

There are multiple drugs and devices presently in various phases of clinical trials to both prevent and treat macular degeneration. These include new drugs to prevent new blood vessel formation, certain anti-inflammatory treatments for the wet form of AMD, and drug-delivery systems to reduce the need for frequent injections for the wet form of macular degeneration. The possibility of transplantation of transplanting healthy cells into a diseased retina is also being investigated.

What is Juvenile Macular Degeneration?

Juvenile macular degeneration is the term for several inherited eye diseases that affect children and young adults. These diseases include Stargardt's disease, Best disease, and juvenile retinoschisis. These rare diseases cause central vision loss that may begin in childhood or young adulthood.

Unfortunately, there is no treatment available to prevent vision loss for these diseases. The diseases are caused by gene mutations passed down in families. Visual aids, adaptive training, and other types of assistance can help young people with vision loss remain active. Researchers continue to look for ways to prevent and treat juvenile macular degeneration (JMD).

The most common form of juvenile macular degeneration is Stargardt disease.

What is Stargardt’s Disease?

 Stargardt's disease is also called fundus flavimaculatus or macular dystrophy. Children and teens with Stargardt disease first notice a problem with their central vision, which may be blurry, distorted, or have dark areas. It may take longer than usual to adjust between bright environments to dark environments. Peripheral vision remains normal, but color perception may be affected in the later stages of the disease, despite the macula disorder. And as the disease progresses, small blind spots (scotomas) often develop in the central visual field.

The progressive vision loss associated with Stargardt disease is caused by the death of specialized, light-sensitive photoreceptor cells in the central portion of the retina called the macula. The retina is the layer of tissue lining the back of the eye, and the macula is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly. 

Stargardt’s Disease (cont.)

Vision loss from Stargardt’s Disease responds very well to magnification which can make reading, seeing signs, faces, the computer, TV, and even driving a possibility.  There is a wide range of optical, electronic and software magnification options to address virtually every need.

There is no cure for Stargardt disease and no treatment to slow its progression. However, genetic treatments already are available for related conditions, and it is likely that they will be available for Stargardt’s disease in the near future.

 

ReferencesChildren's Corner for Macular Degeneration. (n.d.). Retrieved July 14, 2014, from

https://www.childrenscorner.org/about-macular-degeneration  Dahl, A. (2014). Macular Degeneration. Retrieved July 17, 2014, from

http://www.medicinenet.com/macular_degeneration/article.htm  Get Smart Eyes: What is Juvenile Macular Degeneration? (n.d.). Retrieved July 15, 2014, from

http://www.geteyesmart.org/eyesmart/diseases/juvenile-macular-degeneration.cfm  Get Smart Eyes: What is Stargardt Disease? (n.d.). Retrieved July 15, 2014, from

http://www.geteyesmart.org/eyesmart/diseases/stargardt-disease.cfm

References (cont.)Juvenile Macular Degeneration: Stargardt's and Best Disease. (2013). Retrieved July 17, 2014, from

http://www.webmd.com/eye-health/juvenile-macular-degeneration-stargardts Lighthouse International: Age-Related Macular Degeneration (AMD). (2014). Retrieved July 14, 2014,

from http://lighthouse.org/about-low-vision-blindness/vision-disorders/age-related-macular-

degeneration-amd/  Lueck, Amanda Hall. (2004). Functional vision: A Practitioner's Guide to Evaluation and Intervention. New York: AFB Press, American Foundation for the Blind. Roberts, D. (2002). Types of Juvenile Macular Degeneration. Retrieved July 16, 2014, from

http://lowvision.preventblindness.org/eye-conditions/types-of-juvenile-macular-degeneration