Does the Difference in Axial Length Affect the Refractive Outcome?

TL;DR

This study found that axial length does not significantly affect refractive outcomes after cataract surgery using the SRK2 formula.

Contribution

The study demonstrates that axial length differences do not require adjustments in refractive targets during cataract surgery.

Findings

No significant difference in refractive outcomes was found across different axial length groups.

The mean differences between targeted and actual postoperative spherical equivalent were small and not statistically significant.

Abstract

The purpose of this study is to compare axial length (AL) and the refractive outcome after phacoemulsification surgery from 2014 to 2019 at Hospital Sultanah Nur Zahirah, Terengganu, Malaysia.

This was a retrospective record review of all cataract patients who met the inclusion criteria and underwent uneventful superior wound phacoemulsification with nontoric intraocular lens (IOL) by a single surgeon from 2014 to 2019. Using optical biometry or immersion technique, the preoperative AL determined solely via the Sanders, Retzlaff and Kraff 2 (SRK2) formula was selected. The postoperative spherical equivalent (SE) at 6 weeks–12 weeks was retrieved. Using Statistical Package for the Social Sciences version 24.0, the mean differences between targeted and actual postoperative SE were analysed based on the AL.

In this study, 490 eyes of 472 patients aged 25 years old–88 years old (mean age 65.72 years old [SD 8.83]) were involved. There were 162 eyes (33%) in Group A (< 23 mm), 189 eyes (39%) in Group B (23.01 mm–24.0 mm) and 139 eyes (28%) in Group C (> 24.0 mm). The mean AL was 23.63 mm (SD 1.19). The mean differences between the targeted and actual postoperative SE were: −0.09 D (SD 0.60) in Group A, −0.07 D (SD 0.53) in Group B and −0.16 D (SD 0.52) in Group C. No significant difference was found between these groups (P = 0.327).

There was no significant difference in the refractive outcome using the SRK2 formula in different ALs after phacoemulsification surgery. Hence, there is no reason to modify or adjust the targeted SE based on AL.

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