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. 2016 Feb 29:10:35-43.
doi: 10.2174/1874364101610010035. eCollection 2016.

Intra-Ocular Pressure Measurement in a Patient with a Thin, Thick or Abnormal Cornea

Colin I Clement  1 , Douglas G A Parker  2 , Ivan Goldberg  3
Affiliations

Intra-Ocular Pressure Measurement in a Patient with a Thin, Thick or Abnormal Cornea

Colin I Clement et al. Open Ophthalmol J. .

Abstract

Accurate measurement of intra-ocular pressure is a fundamental component of the ocular examination. The most common method of measuring IOP is by Goldmann applanation tonometry, the accuracy of which is influenced by the thickness and biomechanical properties of the cornea. Algorithms devised to correct for corneal thickness to estimate IOP oversimplify the effects of corneal biomechanics. The viscous and elastic properties of the cornea influence IOP measurements in unpredictable ways, a finding borne out in studies of patients with inherently abnormal and surgically altered corneal biomechanics. Dynamic contour tonometry, rebound tonometry and the ocular response analyzer provide useful alternatives to GAT in patients with abnormal corneas, such as those who have undergone laser vision correction or keratoplasty. This article reviews the various methods of intra-ocular pressure measurement available to the clinician and the ways in which their utility is influenced by variations in corneal thickness and biomechanics.

Keywords: Applanation; corneal pathology; corneal thickness; hysteresis; intraocular pressure.

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Figures

Fig. (1)
Fig. (1)
Representative histogram showing a typical ocular response analyzer (ORA) reading. The applanation signal is a function of air jet pressure during the bi-direction applanation process. Corneal hysteresis is defined as the difference between the pressure required to induced inward corneal applanation (P1) and the pressure at which the cornea bends back outward (P2).
See this image and copyright information in PMC

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