Implantation of intraocular pressure sensor in glaucoma patients
Reviewed by Wai Siene Ng

The authors report safety and accuracy of an intraocular intraocular pressure (IOP) sensor placed in the ciliary sulcus during planned cataract surgery. Six patients underwent implantation of the device; a silicone rubber ring-shaped device encapsulating pressure sensitive capacitors and a microcoil antenna. To determine IOP the difference between the absolute pressure sensor in the eye and outside the eye measured by a reader unit held in front of the eye, is calculated. They report a well-tolerated device but rightfully highlight an area of grave concern whereby four out of six patients developed early postoperative sterile anterior chamber inflammation, with two displaying hypopyons. Furthermore, significant pigment dispersion was noted in 50% of patients and all patients showed pupillary distortion. With regards to accuracy, four patients with unexplained IOP shifts, which have been put down to malfunction or a pressure effect on the device during the healing process. The authors should indeed be given credit for their attempt at searching for a continuous IOP monitoring and self non-contact tonometry device. However, with the aforementioned safety issues, size of device necessitating a large corneal incision of about 5.5mm and inexplicable IOP shifts, it would be wise for the group to continue working on refining the sensor shape, size, accuracy and perhaps an alternate site for implantation so as not to impinge onto the uvea, i.e. capsular bag rim or as an IOL piggy back. Otherwise, the risks of an intraocular IOP device far outweighs that of an extraocular one.

Implantation of a novel telemetric intraocular pressure sensor in patients with glaucoma (ARGOS Study): 1-Year results.
Koutsonas A, Walter P, Roessler G, Plange N.
INVESTIGATIVE OPHTHALMOLOGY AND VISUAL SCIENCE
2015;56:1063-9.