Repeatability of a novel corneal indentation device for corneal biomechanical measurement

Kwok Cheung Andrew Lam, Ying Hon, Leo K.K. Leung, David C.C. Lam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

23 Citations (Scopus)


Purpose: The aim of the study was to evaluate the repeatability of a new device for measuring corneal biomechanics. Methods: Twenty-nine normal subjects aged 20-28 years (23.4 ± 1.7 years) underwent measurements of corneal stiffness and tangent elastic modulus using a novel corneal indentation device. Corneal topography, axial biometry and Goldmann applanation tonometry were also performed during the visit. Subjects returned after about 1 week, at approximately the same time, and with the corneal biomechanics, corneal topography and Goldmann applanation tonometry measured again. Both the intrasession and intersession repeatability was assessed. Results: Both the corneal stiffness and tangent elastic modulus demonstrated good intrasession repeatability (corneal stiffness: coefficient of variation = 7.32%, intraclass correlation coefficient = 0.75; tangent elastic modulus: coefficient of variation = 7.34%, intraclass correlation coefficient = 0.84). The mean modulus after normalised to normal intraocular pressure of 15.5 mmHg was 0.755 ± 0.159 MPa. There was no significant difference between the two visits (paired t-tests: p > 0.05). The repeatability [1.96 times the standard deviation (S.D.) of the intersession difference] of the corneal stiffness and the tangent elastic modulus was 0.0022 N mm-1 and 0.197 MPa, respectively. Conclusion: The corneal indentation device has good intrasession and intersession repeatability. It has good potential to measure corneal biomechanics clinically, even at different corneal regions.
Original languageEnglish
Pages (from-to)455-461
Number of pages7
JournalOphthalmic and Physiological Optics
Issue number4
Publication statusPublished - 1 Jan 2015


  • Corneal biomechanics
  • Elastic modulus
  • Intraocular pressure
  • Stiffness

ASJC Scopus subject areas

  • Ophthalmology
  • Optometry
  • Sensory Systems


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