Health Science Center researchers saving sight

by Heather Feldman

 


Nancy McCoy proudly earned her bachelor's degree five days before her 70th birthday. Now, thanks to an eyesight-saving procedure performed at the Health Science Center, she is working on her master's degree

Nancy McCoy woke up one morning in February 1998 and saw nothing but a white fog through her 70-year-old eyes. Diagnosed with macular degenerative disease years earlier, McCoy believed that her eyesight had finally given out and she would remain in the fog for the rest of her years.

Today McCoy has 20/40 vision, drives her car and has returned to school to earn her master’s degree. The fog has lifted and her sight is restored, thanks to remarkable equipment, corrective laser surgery and Wichard A.J. van Heuven, M.D., chairman of the Department of Ophthalmology.

Doctors near her home initially told McCoy that her vision could not be corrected.  Fearing for her future, she turned to the Health Science Center and Dr. van Heuven, who used a state-of-the-art scanning laser ophthalmoscope to find the problem and employed krypton laser treatment to halt the degeneration.

The digital scanning laser ophthalmoscope provides simultaneous angiography of the eye (a procedure in which dye is injected into a vein in the arm and travels through the body to the eye), which enabled Dr. van Heuven to see the vascular choroid layer of the eye. In the past, this layer has been difficult to view because of its location behind the retina. With this technology, Dr. van Heuven was able to identify “hot spots” of damage in McCoy’s eyes.


John Denny, Ph.D., assistant professor of ophthalmology, is doing research on how a newly discovered protein in the retina contributes to eyesight. Dr. Denny's research may lead to new pharmaceutical treatments that might enhance eyesight in people with low vision.


“We were able to use this information to guide our krypton laser treatment,” said Dr. van Heuven. “We were thrilled to find that this resulted in the improvement of her vision.”

Following laser treatments, McCoy’s sight was restored, and she was able to resume her normal schedule, including working on a master’s degree.

“I could not have gone back to school if it hadn’t been for the laser treatment,” McCoy said. “I can’t tell you what it’s like to have the miracle of sight given back to you after you have lost it. The world was black and then the light got turned on.”

Keeping the light on and working properly is the goal of the Department of Ophthalmology’s researchers and physicians.

Located in the Health Science Center’s Robert F. McDermott Clinical Science Building, they are engaged in various forms of eyesight research, including finding better treatments for glaucoma, dealing with macular degeneration and ocular tumors, and providing diabetics with early detection devices and treatments.

Whether conducting basic research on the roles of certain proteins in the eye or performing LASIK surgery to correct vision, the men and women of ophthalmology have one goal—preventing blindness.

 


The Lion's share of support


Eyeing early detection

For diabetics, the risk of eye disease and subsequent blindness is high, and early detection of eyesight problems is a must if sight is to be saved. To that end, researcher Raymond Applegate, O.D., Ph.D., director of the physiological optics laboratory in the Department of Ophthalmology, invented and developed an optical device that allows diabetic patients to monitor their eyes at home between doctor’s visits.

The hand-held device, called a vascular entoptoscope, provides patients with an opportunity to check their own retinal vasculature and search for possible abnormalities such as hemorrhages and microaneurysms.

People who have diabetes run the risk of developing a condition called diabetic retinopathy, which is the leading cause of blindness in working-age Americans. If the disease is appropriately monitored and timely treatment initiated, disease progression can be slowed and in nearly 50 percent of the cases can be prevented from advancing to the more serious stages of the disease process, he said.

“Unfortunately, without regular checkups by an eye-care specialist, by the time a person becomes visually aware of a problem, it is generally too late for treatment to be effective,” said Dr. Applegate. The entoptoscope allows patients to detect potentially vision-threatening events in their own eye prior to actual vision loss.

To use the device, a patient positions one eye in front of an eyepiece, allowing a beam of light to illuminate the eye and create a shadow outline of the retinal blood vessels down to the smallest capillaries. Diabetics are taught to look for changes occurring in the eye that may warrant a doctor’s care.

“Diabetics routinely receive eye exams every six months, but the vascular makeup of the eye can change for the worse between visits,” said Dr. Applegate. “A hand-held device gives patients a cost-effective way to monitor their eyes as often as needed.”  

 


William Sponsel, M.D., assistant professor of ophthalmology, and Yolanda Trigo, research ophthalmic technician, administer a glaucoma test to patient Lisa Ranson using a Frequency Doubling Perimeter (FDP).


Mysteries of the eye

It began with a question.

For John Denny, Ph.D., assistant professor of ophthalmology, the question of how a newly discovered protein in the retina contributes to eyesight is leading to research that may provide new treatments for people with low vision.  

Originally found to be in various parts of the brain, a growth-associated protein, known as GAP-43, recently was discovered in neurons in the retina as well. The mystery was what role this particular protein played in the eye.

In the brain, GAP-43 allows us to remember things such as phone numbers of friends and when to pick up the dry cleaning. In the eye, its inner workings are more mysterious, but Dr. Denny’s research suggests that it may be an intricate part of the changes the retina undergoes when adapting to light and darkness.

Along with its partner protein MARCKS, GAP-43 is now known to be found in certain cells in the eye which release the neurotransmitter dopamine. Through his investigations, Dr. Denny believes that GAP-43, working in conjunction with MARCKS, alters the release of dopamine, supporting the eye’s adaptation processes from light to dark conditions.

The outcome of Dr. Denny’s research may be valuable information on how these proteins operate and how they can be altered by pharmaceuticals to enhance eyesight.

“What we would like to understand is the biochemistry of GAP-43,” said Dr. Denny. “Knowledge of its biochemistry could lead to the development of a drug that could potentially enhance the function of the retina. By enhancing GAP-43, we could enhance vision in someone with low vision.”

To catch a thief

Lisa Ranson, 34, worried that she would inherit glaucoma, the so-called “sneak thief of sight,” from her grandmother, and that it would indeed creep into her life without warning and eventually steal her vision.

Glaucoma runs in Ranson’s family. Her grandmother and two of her great aunts are being treated for the disease. So it was not out of the realm of possibility that Ranson, an outpatient service representative at University Hospital, could have it as well.

Glaucoma is a group of diseases that cause the progressive deterioration of the optic nerve and produce defects in a person’s field of vision. With nearly 3 million people suffering from glaucoma in the United States, it is one of the three major causes of blindness. But the vast majority of those with the disease don’t know they have it until it’s too late. Symptoms often do not show up until the damage has been done and cannot be repaired.

Current tests for glaucoma focus almost solely on pressure, alerting ophthalmologists to patients who have high or low intraocular pressure, which does contribute to glaucoma. It is now believed that larger numbers of people suffering from glaucoma have normal pressures and may never be diagnosed because of testing procedures.

William Sponsel, M.D., chief of glaucoma service and assistant professor of ophthalmology, is trying to change that by developing new testing tools that target patients with normal intraocular pressure.

One such device is a small, lightweight tabletop unit called the Frequency Doubling Perimeter (FDP), which is designed to detect the earliest cases of glaucoma in patients who may normally go untreated. 

The visual function test presents 16 squares of light in wave patterns on the screen that for normal eyes produces a doubling illusion or “ghost lines” between each of the lines introduced to the patient. People with glaucoma do not see all the lines. The test targets the large optic nerves, which is where the disease first begins to do its damage, offering ophthalmologists an opportunity to catch glaucoma earlier.

The FDP requires an average testing time of five minutes, is small and portable, and costs less than larger visual field testing equipment while providing similar results.

“This has proven to be very effective. It is highly specific. Everyone who failed has a problem,” Dr. Sponsel said. “We had people who had 20/15 vision—better than 20/20—and normal intraocular pressure, but failed the FDP. We found they had a problem.”

For Ranson the FDP was quick and easy. In less than 10 minutes, she was pronounced glaucoma-free for now.

“It is still something I need to keep abreast of, but now I am breathing a sigh of relief,” Ranson said.

Early detection is just one of the directions Dr. Sponsel’s glaucoma research is heading.  He also is working on new treatments for the disease, including drugs that may increase blood vessel capacity and provide better circulation. Such treatments also may benefit patients suffering from other types of eye diseases, including macular degeneration. 

“What we learn in the eye, in the treatment of the nerves, may help with age-onset diseases like Parkinson’s and Alzheimer’s. It is exciting to think of the potential our research could have in other areas of medicine,” Dr. Sponsel said.

While Health Science Center researchers work to “lift the fog,” their efforts continue to restore and prevent future loss of one of our most precious senses—sight.