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Br J Ophthalmol 2004;88:466-468 doi:10.1136/bjo.2003.030361
  • Clinical science
    • Scientific reports

Comparison of corneal thickness measurements using Orbscan II, non-contact specular microscopy, and ultrasonic pachymetry in eyes after laser in situ keratomileusis

  1. K Kawana1,
  2. T Tokunaga2,
  3. K Miyata2,
  4. F Okamoto1,
  5. T Kiuchi1,
  6. T Oshika1
  1. 1Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan
  2. 2Miyata Eye Hospital, Miyazaki, Japan
  1. Correspondence to: Dr T Oshika Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575 Japan; toshikamd.tsukuba.ac.jp
  • Accepted 1 September 2003

Abstract

Aims: To compare central corneal thickness measurements of three pachymetry devices in eyes after laser in situ keratomileusis (LASIK).

Methods: Central corneal thickness was measured in 203 eyes after myopic LASIK. Orbscan II scanning slit topography (Bausch & Lomb), SP-2000P non-contact specular microscopy (Topcon), and ultrasonic pachymetry (Tomey) were used in this sequence.

Results: Three devices gave significantly different corneal thickness readings (p<0.0001, repeated measure analysis of variance). The measurements of Orbscan II (445.6 (SD 60.0) μm) were significantly smaller than those of noncontact specular microscopy (467.9 (SD 40.2) μm; p<0.0001, Tukey multiple comparison) and ultrasonic pachymetry (478.8 (SD 41.9) μm; p<0.0001). The value obtained with SP-2000P non-contact specular microscopy was significantly smaller than that taken with ultrasonic pachymetry (p<0.001). There were significant linear correlations between scanning slit topography and non-contact specular microscopy (Pearson’s correlation coefficient r = 0.912, p<0.0001), non-contact specular microscopy and ultrasonic pachymetry (r = 0.968, p<0.0001), and ultrasonic pachymetry and scanning slit topography (r = 0.933, p<0.0001).

Conclusion: In post-LASIK eyes, Orbscan II scanning slit topography significantly underestimated corneal thickness. Non-contact specular microscopy gave smaller thickness readings than ultrasonic pachymetry, but these two units showed an excellent linear correlation.

Footnotes

  • The authors have no commercial or proprietary interest in any of the companies, products, or methods described in this article.

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