Abstract
Purpose: :
To compare white-to-white horizontal corneal diameter (WTW) and anterior chamber depth (ACD) using the Zeiss Meditec Atlas, Zeiss IOLMaster, Orbscan II, and Pentacam automated instruments.
Methods: :
38 eyes of 19 patients were measured using all four instruments and measurements were compared. Statistical evaluation was performed using independent t-tests for differences in means, Pearson correlation coefficient analysis, and the Bland-Altman method for agreement between measurement techniques.
Results: :
The mean horizontal corneal diameter measurements with the Atlas, IOLMaster, Orbscan II, and Pentacam were 12.41 ± 0.35 mm, 12.13 ± 0.31 mm, 11.79 ± 0.30 mm, and 12.06 ± 0.78 mm, respectively. Significant differences were found in the mean WTW diameter between the Atlas and IOLMaster (p<.01), Atlas and Orbscan (p<.01), Atlas and Pentacam (p<.02), and IOLMaster and Orbscan II (p<.01). The best 95% limits of agreement were for the IOLMaster and Pentacam (-1.30, 1.43; r=.76, p<.01). Mean ACD measurements for the IOLMaster, Orbscan II, and Pentacam were 3.55 ± 0.31 mm, 3.51 ± 0.28 mm, and 3.02 ± 0.30 mm, respectively. Significant differences in ACD were found between the IOLMaster and Pentacam (p<.01), and the Orbscan II and Pentacam (p<.01).
Conclusions: :
Measurements of the WTW diameter with the Atlas differ significantly from those using the IOLMaster, Orbscan II, and Pentacam instruments. The greatest agreement in WTW measurement was found between the IOLMaster and Pentacam.
Keywords: refractive surgery: phakic IOL • cornea: clinical science • refractive surgery: corneal topography