Contrast Important for Those with Vision Problems
May 23, 2000 -- It often begins as a small distortion in the center of the field of vision. As it progresses, this area gets larger and larger until it becomes hard to see things right in front of you. More than 13 million people are affected by macular degeneration, which is the leading cause of legal blindness in those over 50.
The macula is the part of the eye that lets us see fine detail at the center of our field of vision. When problems occur in this area, things in the middle of the field of vision become blurred, while our ability to see at the edges remains. This leads to problems with driving, recognizing people at a distance, and other sight-related tasks. Being unable to read is usually the worst part.
Charlotte A. Hazel and colleagues from the Vision Science Research Institute in England recently looked at how vision relates to quality of life for those people with macular disease. Twenty-eight patients were given a comprehensive assessment of how well their eyes were functioning. This was followed by a questionnaire that asked them about such quality of life issues as their ability to get around, read, and participate in leisure activities.
"Reading performance is strongly associated with vision-related quality of life," write Hazel and her group in the journal Investigative Ophthalmology and Visual Science. "The impact that reading ability has on these patient's overall opinion of their vision is understandable when considering the importance of an intact central visual field on tasks such as reading, and the importance of these tasks in daily life."
Bright lights increase the contrast between the page and the writing, which makes it easier to read numbers and letters. The research by Hazel and her colleagues showed that contrast might be even more important than print size in this instance.
Many low-vision aids, such as hand-held magnifying glasses, combine magnification and bright lights to help the person see. Special telescopes may be used to see things far off. Higher-tech solutions include using big and bold type on a computer or using closed circuit TV cameras to project the words onto a screen.