Comparison of AL-Scan and IOLMaster 500 Partial Coherence Interferometry Optical Biometers

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optical Instrumentation

Background:

• Accurate ocular biometry is crucial for intraocular lens (IOL) power calculation in cataract surgery.
• Partial coherence interferometry (PCI) based biometers are widely used for these measurements.
• Comparing newer devices with established ones is essential for clinical adoption.

Purpose of the Study:

• To evaluate the agreement between ocular biometry measurements from the AL-Scan and the IOLMaster 500.
• To assess the comparability of axial length, corneal power, and anterior chamber depth measurements.

Main Methods:

• Measurements of axial length, corneal power, and anterior chamber depth were performed on 86 eyes using both the AL-Scan and IOLMaster 500.
• Statistical analysis included paired t-tests, Pearson correlation coefficients, and Bland-Altman plots.
• Patients were scheduled for cataract surgery.

Main Results:

• Excellent agreement and correlation were observed for axial length measurements between the two biometers (mean 23.46 ± 0.99 mm).
• The AL-Scan showed statistically significant differences in corneal power at the 2.4-mm zone and a deeper anterior chamber depth (0.13 mm).
• Differences in corneal power at the 3.3-mm zone were not statistically significant.

Conclusions:

• Good overall agreement exists between the AL-Scan and IOLMaster 500.
• Statistically significant differences in corneal power and anterior chamber depth require lens constant optimization for precise IOL power calculation.
• These findings are important for surgeons using theoretical formulas for IOL power calculation.