NIU researcher developing
diagnostic tool for eye doctors

by Tom Parisi

A group of researchers led by NIU Chemistry Professor Elizabeth Gaillard is developing a high-tech diagnostic tool that could vastly improve detection of blinding diseases, such as age-related macular degeneration.

Gaillard's research group has built two prototypes of its modified confocal scanning laser ophthalmoscope.

“This is a powerful diagnostic tool that will be enormously useful for clinicians. It also will help us understand how diseases progress,” Gaillard said.

“With most eye disorders, by the time the doctor and patient notice something is wrong, irreversible damage may have already occurred,” she added. “This new tool is able to detect subtle metabolic changes in the tissue of the eye that are indicative of a problem. It should give ophthalmologists a tool for making much earlier diagnoses of retinal disorders. The earlier you intervene, the better the outcome for patients.”

Gaillard's research group includes research scientists James Dillon at Columbia University in New York and Dietrich Schweitzer at the University of Jena in Germany .

The traditional ophthalmoscope is a relatively simple device that has been used for decades to examine the eye's interior structures. Doctors also use a more advanced scanning laser ophthalmoscope, used primarily to evaluate the vascular structure of the eye after a fluorescent dye has been injected. The tool can't detect anomalies at the molecular level and doesn't discriminate differences among a large number of fluorescing compounds found in the human eye.

“There are compounds in the retina that fluoresce under light,” Gaillard explained. “Some of these compounds should be present in healthy tissue, and others accumulate as a result of disease. Our instrument can discriminate between normal and abnormal fluorescing compounds. No commercially available instruments can do that.”

In several seconds, the new modified confocal scanning laser ophthalmoscope produces a series of scans that can be stacked together to produce a multi-dimensional image on a computer screen.

“Confocal means that we're able to achieve very good spatial resolution, so we know where we are in terms of x, y and z coordinates in the retina,” Gaillard said. “We receive temporal information as well, so we can monitor what's happening in real time. This detection system will give doctors vastly more information. The new instrument would allow doctors to detect abnormalities at the molecular or cellular level.”

The two prototypes built by Gaillard's research group are in Germany . The group hopes to build two additional instruments. One would be housed at Columbia University in New York , where Gaillard's group is involved in a study examining genetic links to age-related macular degeneration, the leading cause of blindness in older adults. The study aims to pinpoint genetic mutations responsible for the disease.

The researchers will collect DNA samples from patients in the study. They then hope to correlate retinal abnormalities discovered with the new instrumentation to patients' genetic profiles.

Gaillard hopes the modified confocal scanning laser ophthalmoscope will be available commercially to ophthalmologists within several years. The instrument would need to pass the U.S. Food and Drug Administration (FDA) approval process, which would include clinical trials. In Germany , Gaillard said, the instrument already has been approved by the German equivalent of the FDA and is being used in clinical research on patients.

Development of the new prototypes is just one research aspect being investigated by Gaillard's group, which more broadly examines the effects of light on biological tissue.

“Our research group studies the mechanisms involved in photo-oxidative damage to biological systems, in particular the human eye,” Gaillard said. “Aging oftentimes has to do with oxidizing tissue, and light can accelerate the oxidation process.

“Our work is somewhat unique,” Gaillard added, “because there aren't many researchers doing basic research on the chemistry of eye diseases. We're working on a number of projects that have to do with age-related eye diseases, such as macular degeneration and cataract development, and are developing models that will help us understand these diseases truly at the molecular level.”

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