Differences in corneal astigmatism between partial coherence interferometry biometry and automated keratometry and...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optometry

Background:

• Accurate measurement of corneal astigmatism is crucial for refractive surgery outcomes.
• Partial coherence interferometry (PCI) biometry and automated keratometry are common methods for assessing corneal astigmatism.
• Understanding discrepancies between these methods is essential for clinical decision-making.

Purpose of the Study:

• To compare corneal astigmatism measurements obtained via PCI biometry and automated keratometry.
• To investigate the relationship between measurement differences and corneal topographic patterns.

Main Methods:

• A comparative case series involving 312 eyes.
• Corneal astigmatism was measured using PCI biometry (IOLMaster) and automated keratometry (RK-F1).
• Eyes were grouped based on astigmatism differences, and topographic maps were classified into distinct patterns.

Main Results:

• The asymmetric bow-tie pattern was most prevalent (34.6%).
• Measurement discrepancies were linked to specific topographic patterns, with statistically significant differences observed (P=.015).
• The asymmetric bow-tie pattern dominated groups with smaller measurement differences, while the symmetric bow-tie pattern was more common in the group with larger negative differences.

Conclusions:

• The observed differences in corneal astigmatism measurements between PCI biometry and automated keratometry are influenced by the underlying corneal topography.
• Corneal topography should be considered when interpreting astigmatism measurements from different devices.