Accuracy of New Generation Intraocular Lens Calculation Formulas in Vitrectomized Eyes

Abstract

PURPOSE: To compare the prediction accuracy of new intraocular lens (IOL) calculation formulas (Barrett Universal II [BUII], Emmetropia Verifying Optical [EVO], Kane and Ladas Super formula) and traditional formulas (Haigis, Hoffer Q, Holladay 1, and SRK/T) with Wang-Koch (WK) axial length (AL) adjustment in vitrectomized eyes.DESIGN: Retrospective consecutive case-series study. METHODS: One hundred eleven eyes of 111 patients underwent uneventful phacoemulsification and enVista MX60 implantation after vitrectomy were enrolled and divided into 4 groups according to whether the vitreous cavity was filled with silicone oil. The performance of each formula was evaluated with or without lens constant optimization.RESULTS: Before lens constants optimization, the mean prediction errors (MEs) of all formulas were statistically different from zero (0.14-0.46 diopters [D]) in vitrectomized eyes, except for the Kane formula. The BUII, EVO, Kane, and Haigis had relatively lower mean absolute error (MAE) and median absolute error (MedAE) with optimized constants. No significant systemic bias was found in new formulas for vitrectomized eyes with AL >26 mm (P > .05). The Hoffer Q and Holladay 1 displayed significantly hyperopic shift (0.39 and 0.51 D) for long eyes, which was corrected by the WK adjustment. There were no significant differences in the prediction accuracy of all formulas among 4 subgroups (P > .05).CONCLUSIONS: The BUII, EVO, Kane, and Haigis displayed comparable performance in vitrectomized eyes with optimized constants. In vitrectomized highly myopic eyes, the new formulas and traditional formulas with WK adjustment exhibited satisfactory prediction accuracy. Silicone oil tamponade did not affect the prediction accuracy of formulas using IOLMaster 700.

Cataract Surgery in Post-Vitrectomized Eyes

“…In addition, there were important uncontrolled variables such as the implanted IOL model, which was not the same in all participants of the study. This hyperopic shift in vitrectomized eyes also was reported by Lee et al [68] Recently, another retrospective study published by Tan et al [69] evaluated the refractive results obtained in cataract surgery in vitrectomized eyes by applying next-generation formulas (Barett Universal II, EVO, Kane, and Ladas super formula) against traditional formulas (Haigis, Hoffer Q , Holladay 1, and SRK/T) with Wang-Koch axial length adjustment if required. Before the lens constants were optimized, hyperopic outcomes were noted for all formulas, except for the Kane formula, which revealed no statistically significant bias.…”

The Role of Anterior Chamber Depth on Post-operative Refractive Error After Phacovitrectomy

“…The formulas for IOL selection are all designed for non-vitrectomized eyes. Although some of the new-generation IOL formulas have been demonstrated to be accurate in vitrectomized eyes, 17 this may not be the case with the simpler and more veteran formulas such as the SRK/T. In vitrectomized eyes, the difference in the final effective lens position is likely the result of two factors – the absence of the vitreous, and the possible effect of agents used to fill the vitreous cavity on IOL position.…”

The Postvitrectomy Cataract

“…Fortunately, analyses have shown that the use of optical biometers with newer fourth generation formulas resulted in no difference in the predictive error or difference between the postoperative and formula-predicted spherical equivalent in eyes that previously had silicone oil tamponade. 30 However, not all eyes are amenable to optical biometry and ultrasound biometry sometimes must be used, usually in the context of very dense lenses or in the presence of vitreous opacities. The AL can be separately measured for each ocular segment, with subsequent velocity conversions as have been previously published.…”