Novel contact lens design tracks IOP for continuous 24-hour period

A new and innovative design for a soft contact lens, with an embedded micro-fluidic channel, may be the novel solution to monitoring intraocular pressure (IOP) throughout the course of a day, authors of a new study say.

Study researchers call IOP the "most important modifiable risk factor for glaucoma." Currently, however, patients' IOP is oft-tracked during clinic hours. That time frame captures only a fraction of IOP ups and downs over the course of a day. A longer period of monitoring would provide a more accurate measure of IOP and enable doctors to provide better treatment options to patients.

The researchers' soft contacts worked, measuring IOP variations throughout the day, say researchers affiliated with Queen's University in Kingston, Ontario, Canada; Beijing University in Beijing, China; and Kingston Health Services Centre in Kingston.

"Overall, the need for an improved methodology in tracking the IOP fluctuations through the day is required for a higher-quality approach to monitor the progression of glaucoma," the researchers write in the article, "Non-invasive, intraocular pressure monitoring with contact lens," in the July 2 issue of British Journal of Ophthalmology.

"Capturing the changing corneal curvature, as a direct result in the fluctuating IOP, with an altered soft contact lens provides an inexpensive, quick and easy way to track the IOP," they continue. "The contact lens-based IOP monitoring device evaluated in this report appears able to provide robust measures of change in IOP. The indicator position is linearly responsive, highly sensitive and provides consistent measures across multiple porcine eyes and individual fabricated devices."

According to researchers, changes in IOP induce changes to the curvature of the cornea, which deforms the embedded microchannel and displaces its indicator fluid. Reference markers on the lens calibrate displacement of the fluid and allow for changes in IOP to be calculated.

The researchers note that the device could be manufactured at relatively low costs and, though additional research is needed, it "holds promise in the prevention of glaucoma-related vision loss and blindness."

About 3 million Americans live with glaucoma, a progressive eye disorder that leads to damage to the optic nerve. It is a leading cause of vision loss and many patients don't realize they have the condition because it can be asymptomatic.

Success or failure depends on patients

Mile Brujic, O.D., practices full-scope optometry in Ohio. Among his areas of emphasis in his practice is glaucoma. Dr. Brujic takes note of the myriad innovations occurring with contact lenses to improve the care of patients including the novel, non-invasive contact lens with the microchannel.

A 2017 study looked at the efficacy and safety of the SENSIMED Triggerfish, which was approved for marketing two years ago by the Food and Drug Administration. That device can help assess patients' risk for glaucoma-related vision loss. It measures patients' eye volume over a 24-hour period as a proxy for IOP and transmits that data wirelessly to a data-recorder apparatus.

"These types of studies are indicators of the advanced interest in helping provide better diagnostics in the realm of eye care," Dr. Brujic says. "Assessing IOP measurements are always a challenge because we are testing patients in-office. This (new soft contact) may provide a way to measure IOP in a more continuous way giving the clinician more information to base therapeutic intervention on.

"These technologies are encouraging for both patients and the eye care providers who care for these individuals," he adds.

Still, he agreed with the study's authors that more research is needed. For instance, the lenses were tested on porcine eyes. The proof will be in the patient, he added.

"Assuming the data can be translated into human trials, it may avoid office visits for patients while giving the clinician more continuous information on the patient's IOP throughout the day," Dr. Brujic says.

"Further, as with any contact lens advances, the success or failure of the technology will be in the patients' ability to wear the contact lens comfortably and be able to place the lens appropriately on the eye," he says. "Glaucoma patients are often elderly individuals where dexterity may be a challenge."

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