Intraocular pressure measurement by radio wave telemetry.
OBJECTIVE
To determine the biocompatibility of a new wireless intraocular pressure (IOP) transducer (WIT) in rabbit eyes and to correlate its measurements with other pressure-measuring devices.


METHODS
The WIT is a ring-shaped intraocular device that allows wireless IOP measurements through radiofrequency. It was implanted into six eyes of New Zealand White rabbits after extracapsular lens extraction. A sham rabbit eye with no transducer implanted was used as a control. The animals were observed and examined by microscopy at various intervals up to 25 months after surgery. IOP was measured at various intervals by pneumotonometry, tonometry, WIT, and manometry. The data from the various devices were compared and analyzed for reproducibility. Two eyes were enucleated at 5.5 and 20 months after implantation and analyzed by histology.


RESULTS
The WIT appears to be well tolerated in the rabbit eye, with no evidence of significant inflammation or scar formation by microscopic in vivo examination. Histology did not reveal intraocular inflammation or membrane formation. Repeated IOP measurements with pneumotonometry, tonometry, and the WIT resulted in SDs of 2.70 mm Hg, 3.35 mm Hg, and 0.81 mm Hg, respectively. The concordance between the WIT and direct manometry measurements was high. A downward drift in IOP measured by the WIT was noted in three rabbits, necessitating recalibration.


CONCLUSIONS
The WIT is well tolerated by the rabbit eye. Its measurements are reproducible and in close concordance with manometry. A downward IOP drift warrants further investigation.
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02445, USA.
Amit
A
Todani
Irmgard
I
Behlau
Mark A
MA
Fava
Fabiano
F
Cade
Daniel G
DG
Cherfan
Fouad R
FR
Zakka
Frederick A
FA
Jakobiec
Yuqing
Y
Gao
Claes H
CH
Dohlman
Samir A
SA
Melki
D000818:Animals; D007429:Intraocular Pressure / Q000502:physiology*; D008422:Materials Testing; D011817:Rabbits; D011846:Radio Waves; D015203:Reproducibility of Results; D013686:Telemetry / Q000295:instrumentation*; D014065:Tonometry, Ocular / Q000295:instrumentation*; D014159:Transducers; D014160:Transducers, Pressure