PURPOSE: To investigate interdevice agreement among toric power calculation difference based on corneal topography/ray-tracing aberrometry (iTrace), partial coherence interferometry (IOLMaster 500), and Scheimpflug imaging (Pentacam) for the measurement of anterior corneal astigmatism.
METHODS: The analysis included 101 eyes with regular astigmatism of 101 subjects. The main outcome measures were corneal cylinder power, axis of astigmatism, keratometry values. The toric power and intraocular lens (IOL) power was calculated using online Barrett toric calculator. Interdevice measurement and calculation agreement was assessed using paired sample t-test, and nonparametric test.
RESULTS: Significant interdevice difference existed for astigmatism magnitude, flat keratometry, steep keratometry and mean keratometry between iTrace and IOLMaster (all P < 0.01). Significant interdevice difference existed for flat keratometry, steep keratometry and mean keratometry (all P < 0.001) but not astigmatism magnitude (P = 0.325) between iTrace and Pentacam. Significant interdevice difference existed for astigmatism magnitude, steep keratometry and mean keratometry (all P < 0.01) but not flat keratometry (P = 0.310) between IOLMaster and Pentacam. For toric IOL power calculation, iTrace calculation was statistically higher than IOLMaster (0.49±0.36, P <0.001) and Pentacam (0.39±0.42, P <0.001). Moreover, Pentacam IOL power calculation was statistically lower than IOLMaster (-0.10±0.39, P =0.009). Toricity calculation difference was also existed among the three groups (P = 0.004).
CONCLUSIONS: The toric IOL power and toricity calculation difference based on iTrace, IOLMaster 500, and Pentacam anterior keratometry data should be noticed in clinic practice.