Comparison of central corneal thickness measurements by Orbscan II and Pentacam after corneal refractive surgery.

PURPOSE

To compare the accuracy of postoperative pachymetry between Orbscan II (Bausch & Lomb) scanning-slit corneal topography/pachymetry and the Pentacam (Oculus) rotating Scheimpflug camera.

METHODS

Central corneal thickness (CCT) was determined in 24 patients (48 eyes) before and after laser in situ keratomileusis (LASIK) or Epipolis LASIK (Epi-LASIK) procedures. All eyes were examined by Orbscan II and Pentacam prior to refractive surgery and at the first, fourth, and twelfth week postoperatively. The residual CCT (RCCT) measured by each instrument was compared to the theoretical RCCT.

RESULTS

On the first, fourth, and twelfth week after the refractive surgery, the mean RCCT measurements by Orbscan II were 413 +/- 72, 435 +/- 65, and 440 +/- 69 microm, respectively. Those of Pentacam were 434 +/- 51, 436 +/- 53, and 438 +/- 50 microm, respectively. Orbscan II measurements at the postoperative first and fourth week were significantly smaller than the theoretical RCCT (P < 0.01, P < 0.01, paired t test). There was no statistical difference between the theoretical RCCT and the Pentacam measurements at any stage.

CONCLUSION

The Orbscan II measurement values of postoperative corneas tended to be thinner than the theoretical values, but not those of the Pentacam.