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. 2022 Nov 7;12(1):18845.
doi: 10.1038/s41598-022-23665-0.

A formula to improve the reliability of optical axial length measurement in IOL power calculation

Maddalena De Bernardo  1 , Ferdinando Cione  2 , Luigi Capasso  3 , Alessia Coppola  1 , Nicola Rosa  1
Affiliations

A formula to improve the reliability of optical axial length measurement in IOL power calculation

Maddalena De Bernardo et al. Sci Rep. .

Abstract

To verify the influence of axial length (AL) variations after cataract surgery in IOL power calculation. Patients underwent ophthalmic evaluation before surgery, including optical biometry with IOLMaster 500. Same exams were repeated 2 months after surgery: AL of operated eye was evaluated using two modes (pseudophakic/aphakic options). Mean Keratometry and AL changes were analyzed. Furthermore, refractive prediction error (PE) was back-calculated with Barrett Universal-II, Hoffer-Q, Holladay-1 and SRK/T formulas. To eliminate any systematic error, the mean error (ME) was zeroed-out for each formula. MEs and median absolute errors (MedAEs) of PEs were analyzed. Two-hundred-one operated eyes of 201 patients and 201 opposite eyes were evaluated. In operated eyes, mean AL difference was - 0.11 ± 0.07 mm (p < 0.001) with pseudophakic option and 0.00 ± 0.07 mm (p = 0.922) with aphakic option. There were not-statistically significant differences between MedAE of PEs calculated after zeroing-out the ME with different ALs (p > 0.05). Instead, only MEs of PEs obtained with postoperative ALs-pseudophakic option were not-statistically different from zero (p > 0.05). AL measurement change after cataract surgery is probably due to a systematic error in optical biometer in case of phakic eyes. A correction factor applied to preoperative AL could eliminate any systematic error in IOL power calculation without modifying the lens constant.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Bland–Altman plot of axial length measured before and after cataract surgery utilizing the pseudophakic option.
Figure 2
Figure 2
Bland–Altman plot of axial length measured before and after cataract surgery utilizing the aphakic option.
Figure 3
Figure 3
IOL power calculation formulas evaluation by utilizing phakic-option (Ph), aphakic-option (Ap) and pseudophakic-option (Ps).
See this image and copyright information in PMC

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