November 29, 2004.
Medications often used to treat both heart and eye diseases may have an ADVERSE effect on vision.
The Utah findings parallel the discovery of a gene for retiniitis pigmentosa - one of the most common causes of blindness.
28 year old Alex Brown was diagnosed about eight months ago with retinitis pigmentosa.
Alex Brown: "IF I LOOK DIRECTLY AT YOU I CAN PROBABLY SEE A CIRCLE ABOUT TWO FEET AROUND YOUR HEAD. AND THE REST IS JUST KIND OF GRAYISH."
R.P. typically begins with night blindness then progresses to a point where folks lose all of their peripheral sight and much of their central vision as well.
At the Moran Eye Center, Dr. Kang Zhang and his colleagues have now discovered a genetic mutation that apparently prevents photoreceptor cells - the rods and cones in the eye - from maintaining a chemical balance. Without that control, cells lose their ability to get rid of harmful waste.
But even more sobering, the discovery shows that current medications known as carbonic anhydrase inhibitors may actually upset the acid - base balance in these cells even more.
Kang Zhang, M.D., Ph.D. / University of Utah Moran Eye Center: "If you are using carbonic anhydrase inhibitors which are very widely used in medicine particularly cardiovascular disease and glaucoma, you might run into the long term detrimental effects on vision."
The chemical mechanics involved in this genetic discovery are extremely important because they could lead to the development of a pharmaceutical drug within the next five to ten years that could actually reverse the deficiency.
Dr. Zhang says what we need are medications that will activate or enhance proteins that maintain a healthy chemical balance.
Kang Zhang, M.D., Ph.D. / University of Utah Moran Eye Center: "It is possible to use a pharmacological agent such as a pill or drop to counterbalance the disruption of the acid-base shifts."
Retinitis pigmentosa currently afflicts about 2-million people worldwide.
Dr. Zhang says in addition to new medications, researchers might also be able to replace the defective genes that cause the problem in the first place.
©KSL Television & Radio.
Source URL: http://tv.ksl.com/index.php?nid=46&sid=135621.
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