Corneal thickness measurements: scanning-slit corneal topography and noncontact specular microscopy versus ultrasonic pachymetry

J Cataract Refract Surg. 2003 Jul;29(7):1313-8. doi: 10.1016/s0886-3350(03)00123-8.


Purpose: To compare central corneal thickness measurements taken with 3 pachymetry systems: Orbscan scanning-slit corneal topography/pachymetry, Topcon SP2000P noncontact specular microscopy, and Tomey ultrasonic pachymetry.

Setting: Multicenter study, Tokyo, Japan.

Methods: In 216 healthy eyes of 114 subjects, scanning-slit topography, noncontact specular microscopy, and ultrasonic pachymetry were used in that sequence to record central corneal thickness. In another 20 healthy eyes of 13 subjects, 2 sets of measurements were repeated for each pachymetry to assess repeatability.

Results: The mean central corneal thickness was compatible between scanning-slit topography (546.9 micrometers +/- 35.4 [SD] ) and ultrasonic pachymetry (548.1 +/- 33.0 micrometers); however, noncontact specular microscopy gave a significantly smaller mean (525.3 +/- 31.4 micrometers) than the other 2 tests (P<.001, Tukey multiple comparison). There were significant linear correlations between scanning-slit topography and noncontact specular microscopy (r = 0.846, P<.001), noncontact specular microscopy and ultrasonic pachymetry (r = 0.897, P<.001), and ultrasonic pachymetry and scanning-slit topography (r = 0.852, P<.001). Noncontact specular microscopy tended to show the best repeatability; however, the difference was not statistically significant (P =.663, repeated-measure analysis of variance).

Conclusions: Corneal thickness readings were comparable between scanning-slit topography and pachymetry; noncontact specular microscopy gave significantly smaller values. The measurements of the 3 methods showed significant linear correlations with one another. All methods provided acceptable repeatability of measurements.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Cornea / anatomy & histology*
  • Cornea / diagnostic imaging*
  • Corneal Topography* / standards
  • Humans
  • Microscopy* / standards
  • Middle Aged
  • Reference Values
  • Reproducibility of Results
  • Ultrasonography* / standards