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Agreement between Scheimpflug-based optical biometer with partial coherence interferometry in patients with
Hassan Hashemi1, Alireza Jamali2, Morad Amir Ahmad3
1Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
Scientific Reports
|January 24, 2026
Summary
The Pentacam AXL and IOL Master 500 show good agreement for axial length in keratoconus patients. However, differences in keratometry and other measurements lead to variations in intraocular lens (IOL) power calculations.
Area of Science:
- Ophthalmology
- Biomedical Engineering
Background:
- Accurate intraocular lens (IOL) power calculation is crucial for successful refractive outcomes after cataract surgery.
- Keratoconus (KCN) presents unique challenges for biometry due to corneal irregularity.
- Comparing optical biometry devices is essential for clinical decision-making.
Purpose of the Study:
- To assess the agreement between the Pentacam AXL and IOL Master 500 for measuring biometric parameters in keratoconus patients.
- To evaluate the impact of device differences on intraocular lens (IOL) power calculations using various formulas.
Main Methods:
- A cross-sectional study involving 121 eyes of patients over 60 with keratoconus and cataracts.
- Optical biometry performed using both Pentacam AXL and IOL Master 500.
- IOL power calculated using six formulas (Kane keratoconus, Barret universal 2, Holladay 1, Haigis, Hoffer Q, SRK/T) based on device measurements.
- Agreement analyzed using the Bland-Altman method.
Main Results:
- Good agreement was found for axial length measurements between the two devices (95% limits of agreement: -0.08 to 0.02).
- Discrepancies were observed in keratometry (K1, K2), anterior chamber depth (ACD), and white-to-white (WTW) measurements.
- Significant differences in IOL power calculations were noted, with the Pentacam AXL generally yielding higher power values.
- The Hoffer Q formula showed the most pronounced difference (+0.55 ± 0.92), while Holladay 1 showed the least (+0.34 ± 1.98).
Conclusions:
- The Pentacam AXL and IOL Master 500 demonstrate good agreement for axial length in keratoconus patients.
- Differences in keratometry, ACD, and WTW measurements between devices impact IOL power calculations.
- The choice of IOL calculation formula significantly influences the final power, with the Pentacam AXL and Kane keratoconus formula resulting in higher estimates.
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