New tear research focused on contact lens benefits, risks

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Roderick Fullard, O.D., has been studying tears since 1983, and there was a time people wondered why.

Lucy Kehinde (far right), a doctoral student in the Vision Sciences graduate program examines a patient at UAB Eye Care.
“People used to say to me, ‘You’re studying tears? What’s in tears? They’re like a salt-water solution.’ But nothing could be further from the truth,” says the associate professor in Vision Sciences. “Tears are a very, very complex secretion. We learn more about tears every day, and there is much we do not know.”

Lucy Kehinde, a doctoral student in the Vision Sciences graduate program is the lead researcher on a tears project that looks at the impact contact lens use has on general eye health. Kehinde is working in Fullard’s lab where she is collecting tears from patients to study the biological changes in the eye. These changes can be measured through minor fluctuations in the level of inflammatory proteins called cytokines, which are present in the tear film. Cytokines are strong indicators of overall eye health, especially in contact lens wearers.

“Many studies have been done as to why some patients will develop infections or inflammations or allergies to the contact,” Fullard says. “Lucy’s looking at a very specific aspect of contact lens wear to determine the difference in these inflammatory biomarkers if you take your lenses out every night versus leaving them in continuously for 30 days. That’s become very common these days;  extended-wear lenses require less maintenance and are very convenient. But many patients pay a price. The eyes are more likely to be inflamed and more likely to develop problems and intolerance to contact lenses.”

Patients wear lenses that are approved for 30 days of continuous wear. They are instructed to leave one lens in for 30 days and the lens in the other eye is removed daily. The patient comes to the clinic at UAB Eye Care to collect their tears for Kehinde three or four times during the 30 days.
Kehinde then looks for the difference in the biomarkers or to see if the eye that has extended-wear lenses is showing more inflammatory markers.

“The levels of concentration in the tears will change depending on the health of the eye,” Kehinde says. “Certain diseases have elevated levels of certain cytokines, and others will have decreased levels. The goal of this study is to understand what happens to these cytokines with contact lens wear.”

Collecting the tears
Kehinde presented her initial research findings at the Association for Research in Vision and Ophthalmology annual meeting May 3-7 in Fort Lauderdale, Fla.

The results included 80 volunteers who collected their tears in ultra-thin glass tubes smaller than a coffee stirrer. The participants were trained to hold the collection end of the tube very close to the ocular surface without touching the eye.

The tears collected had to be non-stimulated since cytokine levels are skewed by stimulated or emotional tears.

“Lucy’s collecting tears that are stimulated normally,” Fullard says. “These tears have a very slow turnover rate. Without this basal secretion you wouldn’t be able to see anything but shapes or blurry outlines. Non-stimulated tears form that nice, smooth surface over the eye to help us see clearly.

“By collecting these tears we know as we go from one sample to the next what we’re getting from the surface of the eye and what we’re getting from the main lacrimal gland that secretes tears when we peel onions, for example.”

Kehinde’s research is helping to narrow down the cytokine markers important to eye-disease prevention and treatment.

“We may be able to use this data to develop new diagnostic tools that would identify good candidates for extended-wear lenses or find those who are better suited for daily wear lenses,” she says.

Next research step
Fullard says Kehinde’s study is laying the groundwork for a future study on dry-eye patients.
The ultimate goal is to find a better set of biomarkers than are currently available. Fullard says the upcoming study will use two different but potent treatment methods to see if one is more therapeutic or shows a bigger change in the inflammatory biomarkers.

“If one of the treatments is good we expect the biomarkers to go down substantially,” Fullard says.
Soon, Fullard also will begin a study collecting cells from the surface of the white part of the eye and looking at the RNA. He hopes to match it to the human genome and see all of the biomarkers that are being expressed on the surface of the eye.

“If we actually see this at the genetic level, we can use chips to sequence the entire human genome,” Fullard says. “That has so much potential because we can look at the expression of all of these genes and see what changes after treatment.”