Macular degeneration (MD) causes deterioration of central vision. There are two types of macular degeneration: wet and dry. Vision loss may be gradual with the dry form of age-related macular degeneration (ARMD). However, older people with the advanced wet form of the disease, and young people with a type of juvenile macular degeneration known as Stargardt's may experience rapid vision loss. The effects of the disease may include sensitivity to glare, difficulty reading and performing daily living skills, decreased color perception and reduced contrast sensitivity. Blind spots called scotomas may also impact function and safety.
Sensitivity to Glare
Increased sensitivity to glare becomes increasingly common as people age. According to MedRounds Publications Inc., this is especially true for people who suffer from ARMD, and the problem may be even worse if the person has cataracts. Ironically, people with MD need more light in order to see, but find that glare negatively impacts vision. In fact, they may see better at night while using their peripheral vision. Special color filters that are designed to reduce glare can be worn over eyeglasses. Usually, yellow or an orange color works well. Wearing a visor and arranging the home so that the sun does not shine on the television or computer, avoiding polished floors, and decorating with sheer curtains that allow sunlight in but block glare, may help.
Impact on Central Vision
Macular degeneration destroys central vision---the vision used to see sharp details through use of central gaze. Although, peripheral, or side, vision remains intact, it does not achieve the sharp visual acuity required for reading and other close work. Some individuals have major vision loss in only one eye and benefit from wearing an eye patch while doing detail work to use only the better eye. Special reading glasses may be prescribed, or the individual may benefit from improved lighting, use of a magnifier, or adaptive equipment such as tactile bump dots on appliances that indicate settings.
Color Perception
The macular has the greatest number of cells, called cone cells that provide color vision. According to optometrists Richard L. Windsor, O.D. and Laura K. Windsor, O.D., patients with MD can still see colors, but perception may become more impaired as the disease advances. They may have particular difficulty differentiating dark colors, such as black, brown and navy blue from one another, and benefit from organizing their wardrobes so that certain colors are all together in one section.
Contrast Sensitivity
Contrast sensitivity refers to how well a person can see an object against a background of the same or similar color. Maureen A Duffy, author of "Making Life More Livable" gives the example of how it is difficult to see a white plate on a light tablecloth, or a brown coffee table against a dark carpet. As persons with MD struggle to see objects that get lost in the background, they should adapt their homes with high contrast such as using dark drinking glasses for milk, and light colored cups for black coffee.
Blind Spots
During the advanced stage of MD, blurred spots in the central vision may get larger and darker to the point of creating a blind spot called a scotoma. The individual may benefit from working with a low vision occupational therapist to identify where the scotoma is and how to become aware of it while walking and performing daily activities. In some cases, the person may experience hallucinations in the blind spot, a condition called Charles Bonnet syndrome. Hallucinations typically involve people or animals that look smaller than normal and seem to fit inside the person's surroundings, such as a monkey sitting on top of the refrigerator.
References
- Macula Vision Research Foundation: Charles Bonnet Syndrome
- American Macular Degeneration Foundation: What is Macular Degeneration?
- "Age-Related Macular Degeneration"; What You Should Know; National Eye Institute; 2003
- Macular Degeneration/Dystrophies
- Med Rounds Publications: Glare and Age-related Macular Degeneration
