Implantable IOP Measurement Device Shows Agreement With Applanation Tonometry

An implantable, intraocular pressure (IOP)-measuring device demonstrates high levels of agreement with measurements obtained via applanation tonometry, according to research published in Ophthalmology. No adverse events were noted and the device was well-tolerated among patients. 

Researchers enrolled 24 patients (mean age, 65.2 years; 50% women) with primary open-angle glaucoma (POAG) in a prospective, multicenter, single-arm clinical trial to test agreement between an implantable IOP device and applanation tonometry. Patients underwent comprehensive exams which included best corrected visual acuity (BCVA) and IOP measurements, slit lamp analysis, and fundoscopy. Follow-up visits were conducted at 1, 3, 10, 30, 90, 180, 270, and 360 days following the baseline assessment. The primary endpoint was to evaluate the level of agreement between the 2 devices, while the secondary endpoint was the number of patients experiencing device-related adverse effects.

The analysis included 536 IOP measurements gathered from the implantable device. After a 3-month period during which the IOP values of the implantable device were significantly higher than those obtained by applanation tonometry (maximum difference, 2.5 mm Hg), the overall difference declined and stabilized until the conclusion of the study. Mean overall difference between the devices was 0.8 (95% CI, -5.1 to 6.7) mm Hg, which improved to -0.2 (95% CI, -4.6 to 4.2) mm Hg in the final 264 measures. 

Patients reported several minor complications following implantation including hyphema (n=9), superficial punctate keratitis (n=2), postoperative leakage (n=1), and choroidal detachment and hypotony (n=1), but no serious adverse events occurred, according to the report. Anterior segment optical coherence tomography (AS-OCT) assessment revealed no instances of device migration, rotation, or dislocation. 

“[The device’s] repeated measures automatically generate an individual IOP profile that can be shared with their treating ophthalmologist to adapt their management based on the short- and long-term fluctuations observed,” according to the researchers. “Not only were these fluctuations shown to play a significant role in glaucoma progression, but in times when the COVID-19 pandemic has led to the delay or cancellation of 84.6% of glaucoma appointments in some area and telemedicine is rapidly developing, IOP telemetry may be particularly relevant.”

Study limitations include a small and homogenous patient population.

Disclosure: This study was supported by Implandata Ophthalmic Products GmbH. Multiple study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.