Dynamic contour tonometry over silicone hydrogel contact lens

Kwok Cheung Andrew Lam, Jimmy S H Tse

Research output: Journal article publicationJournal articleAcademic researchpeer-review

6 Citations (Scopus)


Purpose This study compared the measurements of intraocular pressure (IOP) and ocular pulse amplitude (OPA) using the Dynamic Contour Tonometry (DCT) over silicone hydrogel contact lenses of different modulus. Corneal biomechanics were also measured using the Ocular Response Analyzer (ORA). Methods Forty-seven young (mean age 22.3 years, standard deviation 1.2 years) subjects had IOP, OPA, corneal hysteresis (CH) and corneal resistance factor (CRF) measured without lens and with two brands of silicone hydrogel contact lenses. Each eye wore one brand followed by another, randomly assigned, and then the lenses switched over. Difference and agreement of IOP and OPA with and without silicone hydrogel contact lens were studied. Results The right and left eyes had similar corneal curvatures, central corneal thicknesses, IOP, OPA and corneal biomechanics at baseline. No significant difference was found in CH and CRF when they were measured over different contact lenses. IOP demonstrated a greater difference (95% limits of agreement: 2.73 mmHg) compared with no lens when it was measured over high modulus silicone hydrogel lenses. Agreement improved over low lens modulus silicone hydrogel lenses (95% limits of agreement: 2.2-2.4 mmHg). 95% limits of agreement were within 1.0 mmHg for OPA. Conclusions This study demonstrated the feasibility of DCT over silicone hydrogel lenses. Low lens modulus silicone hydrogel contact lens in situ has no clinical effect on DCT.
Original languageEnglish
Pages (from-to)91-99
Number of pages9
JournalJournal of Optometry
Issue number2
Publication statusPublished - 1 Jan 2014


  • Corneal hysteresis
  • Corneal resistance factor
  • Intraocular pressure
  • Lens modulus
  • Ocular pulse amplitude

ASJC Scopus subject areas

  • Optometry
  • Medicine(all)


Dive into the research topics of 'Dynamic contour tonometry over silicone hydrogel contact lens'. Together they form a unique fingerprint.

Cite this