Comparison of refractive error in phacovitrectomy for epiretinal membrane using ultrasound and partial coherence interferometry

Abstract

PURPOSE: To compare the postoperative refractive error (RE) using A-scan ultrasound (US) and partial coherence interferometry (PCI) after phacovitrectomy for idiopathic epiretinal membrane (iERM) and cataract.

METHODS: Eighty-eight participants (88 eyes) with iERM and cataracts underwent phacovitrectomies with internal limiting membrane removal. Postoperative RE was the main outcome measured, calculated by subtracting intended spherical equivalent (SE) from 6-month postoperative SE. Secondary outcomes included axial length (AL) measured by 2 methods, change in best-corrected visual acuity (BCVA), and change in central subfield thickness (CSFT).

RESULTS: Mean postoperative RE using US showed greater myopic shift compared with that using PCI (-0.569 ± 0.571 D vs -0.169 ± 0.415 D, respectively, p<0.001). The 6-month postoperative RE was within ±0.50 D in 43.2% (38/88) using US vs 84.1% (74/88) using PCI and within ±1.00 D in 84.1% (74/88) using US vs 96.6% (85/88) using PCI. Mean AL measured by US was shorter than that measured by PCI (23.50 ± 1.27 mm vs 23.58 ± 1.30 mm, respectively, p<0.001). Postsurgery, BCVA improved from 0.374 ± 0.264 logMAR to 0.144 ± 0.124 logMAR (p<0.001), and CSFT decreased from 449.2 ± 78.5 ?m to 378.2 ± 47.0 ?m (p<0.001). The BCVA improvement significantly correlated with decreased CSFT (R = 0.268, p = 0.011).

CONCLUSIONS: Estimation of intraocular lens power for phacovitrectomies for iERM and cataracts is more accurate when assessed by PCI than by US.