Repeatability of Corneal Thickness Measured Using an Oculus Pentacam

Purpose. To evaluate the repeatability of corneal thickness measurements over time, obtained with an Oculus Pentacam. Methods. Measurements of corneal thickness (apical and peripheral) were performed at three different sessions in one eye of 23 healthy subjects, using an Oculus Pentacam instrument. In each session, three consecutive measurements were taken (without realignment) by the same observer. Measurements were performed, immediately after a blink. Results. Mean values obtained were in agreement with published literature values for central corneal thickness (mean ± SEM: 546.23 ± 5.24 μm for first session over the first 1 min, 545.13 ± 5.49 μm for second session 1 h later, and 543.23 ± 4.96 μm for the third session measured 1 week later). The data showed an increase in corneal thickness towards the periphery with a decrease in intraobserver reproducibility. The confidence limits in the Bland and Altman charts for pachymetry at the corneal apex ranged between −10.91 μm and 13.00 μm within the first session measured over the first 1 min, −13.43 μm to 11.23 μm between the first and second sessions after 1 h and −11.99 μm to 10.02 μm between the first and third sessions after 1 week. The confidence limits were found to increase towards the peripheral cornea. There was no significant difference in within-subjects variance between the three time scales (p > 0.05 for all parameters measured). Conclusion. Our data showed that the Oculus Pentacam provides repeatable measures of corneal thickness when measured within a few seconds, after 1 h, and 1 week.

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