Clearview Eye and Laser Medical Center
Tuesday, April 8, 2008
Scotomas and Vision Loss
Wouldn’t it be wonderful if, as we age, we could find out quickly and easily if we have early glaucoma damage or incipient age-related macular degeneration? Most would answer with a resounding "yes." The "twinkle after" effect is a visual illusion that foils the brain’s automatic filling in of small blind spots in the visual field and offers the possibility that patients could notice their scotomas earlier. Detecting scotomas early could lead to early drug treatment and some preservation of vision.
According to Peter J. Bex, Ph.D. and assistant professor of ophthalmology at Harvard University, "We have built-in mechanisms that prevent us from being aware of loss of vision. Even if you close one eye, the location of the physiological blind spot is filled in." He continues by saying, "Even when you have a real disease with a blind spot, you may not be aware of it because filling in takes over."
Dr. Bex and two colleagues recruited eight patients with scotomas (most of them caused by macular degeneration) and performed tests to map their scotomas. Four of the patients’ scotomas could not be measured because of filling in.
They then tested the "twinkle after effect" by first showing the patients a large, touch-sensitive display screen for 15 seconds, followed by a solid gray screen for 15 seconds. After several cycles of this, the patient was told to look at the gray screen and draw around any area that appeared unusual. They described what they saw as a "twinkling" or a "moving cloud." The twinkling areas corresponded well with the scotomas measured. Of the four patients who could not be measured with conventional tests, three experienced the twinkle after effect.
The goal of this study is to adapt the system so that people can have a simple test to check their own vision at home. This may ensure they see an ophthalmologist in time for any possible treatment, and giving them a chance to preserve their vision.
To learn more about vision loss and what can be done about it, please contact Clearview Eye and Laser Medical Center in San Diego, California today.
According to Peter J. Bex, Ph.D. and assistant professor of ophthalmology at Harvard University, "We have built-in mechanisms that prevent us from being aware of loss of vision. Even if you close one eye, the location of the physiological blind spot is filled in." He continues by saying, "Even when you have a real disease with a blind spot, you may not be aware of it because filling in takes over."
Dr. Bex and two colleagues recruited eight patients with scotomas (most of them caused by macular degeneration) and performed tests to map their scotomas. Four of the patients’ scotomas could not be measured because of filling in.
They then tested the "twinkle after effect" by first showing the patients a large, touch-sensitive display screen for 15 seconds, followed by a solid gray screen for 15 seconds. After several cycles of this, the patient was told to look at the gray screen and draw around any area that appeared unusual. They described what they saw as a "twinkling" or a "moving cloud." The twinkling areas corresponded well with the scotomas measured. Of the four patients who could not be measured with conventional tests, three experienced the twinkle after effect.
The goal of this study is to adapt the system so that people can have a simple test to check their own vision at home. This may ensure they see an ophthalmologist in time for any possible treatment, and giving them a chance to preserve their vision.
To learn more about vision loss and what can be done about it, please contact Clearview Eye and Laser Medical Center in San Diego, California today.
posted by Lynn at 8:37 AM
-
858.452.3937
-
::
Sandy T. Feldman, M.D., M.S. :: ClearView Eye and Laser Medical Center
6255 Lusk Blvd., Suite 100 :: San Diego, California 92121
“She’s the Surgeon to See”
Previous Posts
- Can I have LASIK after cataract surgery?
- Can diabetics have LASIK?
- Can you be too old to have LASIK
- How old do you have to be to have LASIK?
- When can I drive after PRK?
- When can I drive after LASIK?
- What is the recovery process like for PRK, should ...
- After my LASIK surgery, how soon will I be able to...
- What if I move or blink during LASIK?
- Does LASIK hurt during surgery, what about as I am...
<< Home