Dynamic palpation device to evaluate IOP; simulation on a mechanical eyeball system

Matthias R Hien, R. L. Reuben

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The only sure diagnostic indicator of Glaucoma is the intra ocular pressure IOP. When the IOP increases to about 2 times the normal average pressure of 16 mmHg (2.1kPa) the pressure in the eyeball affects the optic nerve and causes visual distortion and, ultimately, can cause blindness.

The Goldmann tonometer is recognised as the "gold standard" for measuring IOP. However, this test does not take into account the effect of changes in central cornea thickness (CCT), creep of the cornea and drainage of the aqueous humour (AH) from the anterior chamber. These factors, two of which are time-dependent, play a very important role for measuring the real IOP in vivo. Whereas, static devices are not able to record these parameters, a dynamic palpation instrument is able to separate the effects of IOP, CCT, creep and fluid drainage. To assess this behaviour, a mechanical eyeball was designed capable of simulating fluid drainage through a range of nozzle sizes, CCT through a change in membrane thickness and IOP using a variable hydrostatic head. The device which was driven by a piezo actuator was used to palpate the surface of the membrane with a range of frequency up to 60Hz with an amplitude of max 0.15 mm, whilst measuring the force, displacement and pressure as a functions of time. Significant differences in amplitude ratio and phase lag were achieved each characteristic of the IOP, membrane thickness and/or nozzle size.

Original languageEnglish
Title of host publicationWorld Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany
Subtitle of host publicationVol. 25/11 Biomedical Engineering for Audiology, Ophthalmology, Emergency & Dental Medicine
EditorsOlaf Dössel , Wolfgang C Schlegel
PublisherSpringer
Pages339-342
Number of pages4
ISBN (Electronic)978-3-642-03891-4
ISBN (Print)978-3-642-03890-7
DOIs
Publication statusPublished - 2009
EventWorld Congress on Medical Physics and Biomedical Engineering - Munich, Germany
Duration: 7 Sep 200912 Sep 2009

Publication series

NameIFMBE Proceedings
Volume25/11
ISSN (Print)1680-0737

Conference

ConferenceWorld Congress on Medical Physics and Biomedical Engineering
CountryGermany
CityMunich
Period7/09/0912/09/09

Keywords

  • MODEL
  • INTRAOCULAR-PRESSURE
  • Glaucoma
  • APPLANATION TONOMETRY
  • Artificial mechanical eyeball
  • CORNEAL THICKNESS
  • EYE
  • Dynamic measurement

Cite this

Hien, M. R., & Reuben, R. L. (2009). Dynamic palpation device to evaluate IOP; simulation on a mechanical eyeball system. In O. Dössel , & W. C. Schlegel (Eds.), World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany: Vol. 25/11 Biomedical Engineering for Audiology, Ophthalmology, Emergency & Dental Medicine (pp. 339-342). (IFMBE Proceedings; Vol. 25/11). Springer. https://doi.org/10.1007/978-3-642-03891-4_90