title: Reliable intraocular pressure measurement using automated radio-wave telemetry.
abstract: OBJECTIVE
  To present an autonomous intraocular pressure (IOP) measurement technique using a wireless implantable transducer (WIT) and a motion sensor.
  
  
  METHODS
  The WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS) comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline) IOP.
  
  
  RESULTS
  On average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg) and mean vehicle IOP (13.27±2.1 mmHg) (P=0.45), suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001), and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001). Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001). Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute), during which the IOP is not expected to change.
  
  
  CONCLUSIONS
  IOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results.
authors: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.
authors: Eleftherios I
authors: EI
authors: Paschalis
authors: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.
authors: Fabiano
authors: F
authors: Cade
authors: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.
authors: Samir
authors: S
authors: Melki
authors: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.
authors: Louis R
authors: LR
authors: Pasquale
authors: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.
authors: Claes H
authors: CH
authors: Dohlman
authors: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.
authors: Joseph B
authors: JB
authors: Ciolino
keywords: IOP; MEMS; implant; intraocular; pressure transducer; wireless