Eyeworld

45 EW GLAUCOMA by Liz Hillman EyeWorld Senior Staff Writer ations rather than practical, clinical situations. "But it has been tremen- dously helpful in our understand- ing of what happens at night," she acknowledged. There is also Icare Home (Icare, Raleigh, North Carolina), an FDA-approved, externally applied, at-home tonometer operated by the patient with data retrieved by the healthcare provider. This device, though not continuous, allows pa- tients to collect several IOP measure- ments throughout a time period as directed by their physician. The ideal continuous IOP monitoring device would come in two iterations, Dr. Sit said. He said a non-invasive, well-tolerated mon- itoring device, like a contact lens, could be useful to learn more over a short time frame (days) about IOP patterns in glaucoma suspects or those in early stages of the disease who are not surgical candidates. For patients with established glaucoma, physicians want a more permanent monitoring device that could help detect risk of progression, and pro- vide alerts if certain pressure thresh- olds are crossed, Dr. Sit said. There has been a lot of work on this latter front thanks to advanc- es in extreme miniaturization of electronics in order to produce a biocompatible sensor that needs little calibration, Dr. Moster said. "I think it could be coupled with cataract surgery in the form of a capsular tension ring or perhaps embedded in an implant. It could be used as a standalone device within the sclera or perhaps attached to a shunt or any kind of MIGS device. The sky is the limit as to where this very small, biocompatible device will go. It all depends on the amount of inflammation it might cause," she said. "The goal is to have it as inert as possible, as small as possible, and to be recharged in a way that there is little need for the patient to pay attention to this. It will need to be easily rechargeable and battery friendly so that just sleeping at the bedside near a wire- less charger can enable this to last for 10–20 years." Some companies making head- way on such devices are Implandata Ophthalmic Products (Hannover, Germany) with EyeMate, which Devices for continuous IOP monitoring might not be that far off I ntraocular pressure and its association with glaucoma dates back to the 10th century, with more widespread recogni- tion and understanding of this association becoming established in the 19th century. 1 Since then, mea- suring intraocular pressure to detect risk of progression has become stan- dard of care for glaucoma patients and suspects. Despite its long history, there are still many unknowns about IOP, said Arthur Sit, MD, professor of ophthalmology, vice chair of clinical practice, Department of Ophthal- mology, Mayo Clinic, Rochester, Minnesota. But a better under- standing might not be far off with advances in the development and testing of continuous IOP-monitor- ing devices. "Right now, we only measure IOP a few times a year for a few sec- onds when a patient is in the clinic during office hours," Dr. Sit said, acknowledging that research has provided insight on what happens, generally, with IOP and circadian patterns. "But this still doesn't tell us what happens to an individual patient's IOP during activities of living." Marlene Moster, MD, professor of ophthalmology, Sidney Kimmel Medical College at Thomas Jeffer- son University, Philadelphia, said one of the remaining mysteries in understanding glaucoma is IOP over time. What happens at night? What happens during exercise? Is it the same in every patient? What is the patient's response to a medi- cation change or surgery? These are all questions that continuous IOP monitoring could provide. And, ac- cording to Dr. Moster, a device that could truly provide this information is not far off. Only one device—Triggerfish (Sensimed, Lausanne, Switzerland) —is currently approved by the U.S. FDA to provide some of these insights. The 24-hour contact lens monitoring device, however, does not measure IOP directly, rather ocular volume change. Dr. Moster also said she thinks Triggerfish is tailored more toward research situ- Imagining the future of IOP monitoring March 2019 ICare Home is a portable tonometer that allows patients to measure their IOP at home during several parts of the day/night as prescribed by their ophthalmologist. Source: ICare USA Triggerfish is an external contact lens that is the only FDA-approved, wearable device for continual monitoring, but it does not directly measure IOP. Source: Sensimed continued on page 47 Device focus

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