Comparison of Preoperative Measurements with Intraoperative Aberrometry in Predicting Need for Correction in Eyes with Low Astigmatism Undergoing Cataract Surgery

Abstract

Purpose

To determine whether intraoperative aberrometry during cataract surgery measures higher levels of absolute astigmatism than preoperative biometry readings and which method yields a lower, final level of astigmatism if the two do not agree.

Patients and Methods

Retrospective record review of all patients who underwent uncomplicated cataract surgery from February 2015 to May 2019 with planned intraoperative aberrometry. Data analysis included preoperative keratometry, total astigmatism as measured by intraoperative aberrometry, intraocular lens model and power used, and postoperative manifest refraction ≥1 month after surgery. The primary outcome measure was the proportion of patients requiring astigmatism correction (≥0.5 D) when measured by preoperative keratometry vs intraoperative aberrometry. Secondary outcomes included postoperative residual astigmatism, where adjusted preoperative astigmatism fell below the 0.5 D threshold for treatment but the intraoperative measurement was ≥0.5 D or ≥1.0 D.

Results

A total of 451 patient records were evaluated. Intraoperative aberrometry measured statistically higher levels of mean astigmatism than keratometry (0.86 D vs 0.79 D, respectively; P < 0.0001) and significantly greater astigmatism among patients with 0.5–1.5 D of adjusted preoperative astigmatism (P < 0.0001). Significantly more patients qualified for with-the-rule astigmatism correction when measured by intraoperative aberrometry (n=339; 75%) than by preoperative keratometry alone (n=314; 70%); P < 0.03. This difference did not hold for against-the-rule or oblique astigmatism. For patients whose preoperative biometry astigmatism differed from intraoperative biometry, final postoperative astigmatism was lower when corrected if the adjusted preoperative and intraoperative measurements had a vector difference of <0.5 D, but there was no additional benefit in final astigmatism reduction when the vector difference was ≥0.5 D.

Conclusion

Using intraoperative biometry readings can produce lower postoperative astigmatism than using preoperative biometry readings, but caution should be used when interpreting intraoperative readings that disagree with preoperative measurements with a vector magnitude of >0.5 D.

Keywords:

• aberrometry
• astigmatism
• cataract surgery
• toric IOL

Data Sharing Statement

The datasets used and/or analyzed for the purposes of this study are available from the corresponding author on reasonable request.

Ethics Approval and Informed Consent

This study was performed under the supervision of Aspire IRB (Santee, California) under Protocol ID “1909 ORA vs Biometry” and following the principles of the Declaration of Helsinki. Informed consent was provided for the surgery, but the data was anonymized for analysis purposes and exempt from additional informed consent.

Acknowledgments

This paper was presented as a poster at the 2020 ASCRS Virtual Symposium and at the 2019 American Academy of Ophthalmology meeting, also as a poster. Michelle Dalton, ELS, provided medical writing; this was funded by Research InSight, LLC.

Disclosure

Dr Hovanesian reports grants from Alcon, during the conduct of the study. The author reports no other competing interests related to this work.

Additional information

Funding

This was an investigator-initiated study; limited funding was received from Alcon.