Contact lens helps predict speed of glaucoma progression

Continuous monitoring using a sensor-laden contact lens could be a beneficial adjunctive procedure in assessing patients' risk for glaucoma-related vision loss, study results indicate.

Presented at the American Glaucoma Society 2017 Annual Meeting, a study by Carlos Gustavo De Moraes, M.D., et al,, showed that 24-hour intraocular pressure (IOP) monitoring using a contact lens sensor could help doctors predict the speed of vision loss in 78% of treated glaucoma patients over the subsequent five years.  

The study followed 445 patients with open-angle glaucoma in 13 countries using the SENSIMED Triggerfish, a contact lens monitoring system approved last year by the U.S. Food and Drug Administration, but available in Europe for some time. The device measures patients' eye volume continuously as a proxy for IOP, and transmits that data wirelessly to a data-recorder apparatus. This 24-hour monitoring permits a wide range of measurements, including how fast IOP increases and peaks at night—an indicator for patients' progression.  

Glaucoma, the second leading cause of blindness in the U.S., is a group of eye disorders leading to progressive damage of the optic nerve. Elevated IOP is the main risk factor, yet IOP varies throughout the day and may not be abnormally high when a patient presents for an eye exam. Tonometry takes a snapshot of IOP at the time, but diurnal variations can yield higher results as IOP tends to increase as patients sleep.  

It's for this reason that this study's findings—more than three-quarters of patient outcomes could be accurately identified as fast or slow progression of vision loss—prove so compelling.  

"These findings suggest that contact lens sensor parameters can be used to assess future rates and risk of visual field progression and could be extrapolated to a more general population," Dr. De Moraes' study notes.  

Data influencing care?  

However, there's a question of what to do with all that data, says Michael Chaglasian, O.D., chief of staff at The Illinois Eye Institute in charge of glaucoma services. While there is great anticipation for this contact lens monitoring system coming to market, the data question looms.  

"This will be a huge leap in how much new or additional IOP information that a practitioner would have, and you have to know what to do with that data once you have it," Dr. Chaglasian says. That said, easily interpretable data could indeed be a game-changer in glaucoma care.  

Early intervention is key in glaucoma management as optic nerve damage leads to irreversible vision loss, often with no advanced warning. That's why IOP is such a critical measurement.  

"If we can assess someone and know early on if they would have an easy course of glaucoma or a rapid progressor—someone needing more aggressive treatment—that can make all the difference in effective treatment," Dr. Chaglasian says. 

"This contact lens sensor could help the practitioner guide the aggressiveness of treatment and intervention, and provide additional information that is critical to the early assessment for the patient with glaucoma."  

Read more about hi-tech contact lenses in the July/August 2014 edition of AOA Focus(member login required).