Intraocular Lens Formula Comparison of Flanged Intrascleral Intraocular Lens Fixation with Double Needle Technique

Abstract

Purpose To analyze visual outcomes and accuracy of intraocular lens (IOL) calculation formulas in predicting postoperative outcomes in patients undergoing flanged intrascleral IOL fixation. Design Case Series. Subjects Twenty-three patients who had undergone secondary IOL placement using flanged intrascleral fixation technique. Methods Retrospective chart review. Main Outcome Measures Corrected distance visual acuity (CDVA) and postoperative spherical equivalent based on manifest refraction. Results Visual acuity improved from 20/577 to 20/58. Overall, the actual refraction was 0.06 D more myopic than predicted. Holladay 2, Sanders Retzlaff Kraff/Theoretical (SRK/T) and Barrett Universal II resulted in mild myopic surprise (−0.55, −0.18 and −0.20 D). Haigis and Hill-RBF (Radial Basis Function) resulted in mild hyperopic surprise (+0.28 and +0.28 D). Hoffer Q and Holladay 1 were the most accurate (−0.02D and −0.08 D). Conclusion Flanged intrascleral IOL fixation improved vision even in patients with other posterior segment pathologies. The effective lens positioning is likely similar to in-the-bag positioning. Hoffer Q and Holladay 1 formulas with in-the-bag calculations were the most accurate.

Comparison of Refractive Prediction Error by Axial Length in Flanged Intrascleral Intraocular Lens Fixation

“…Axial length is a major factor affecting refractive prediction error, 8 and the selection of IOL calculation based on axial length is not commonly known in intrascleral IOL fixation. There are many reports of refractive prediction error in intrascleral fixation with other IOLs have been seen, 4,5,[9][10][11][12] but few reports have used PN6A, 3,4 and we consider it very important to understand the trend of refractive prediction error at each institution.…”