TITLE:
The Effect of Anterior Corneal Astigmatism Orientation on Toric Intraocular Lens Outcomes
AUTHORS:
Eugene A. Lowry, Jonathan Li, Sundeep K. Kasi, Seth Blumberg, Priya Morjaria, Steven Schallhorn, Ayman Naseri
KEYWORDS:
Toric, Lens, Astigmatism, Cataract Surgery, Refractive Lens Exchange
JOURNAL NAME:
Open Journal of Ophthalmology,
Vol.9 No.2,
May
9,
2019
ABSTRACT: Background: It is unclear whether post-operative errors after toric intraocular lens implantation would be more amenable to pre-operative correction with a fixed adjustment or a correction ratio that scales with the magnitude of pre-operative astigmatism. Purpose: To investigate the effect of pre-operative anterior corneal astigmatism orientation on outcomes of toric intraocular lens implantation in a large population. Methods: A retrospective cohort study of 625 patients undergoing refractive lens exchange through a superior clear corneal incision with Oculentis M-Plus toric intraocular lens implantation at an Optical Express, Inc. located in the United Kingdom and Ireland. Patients were stratified by axis of astigmatism on automated keratometry as with-the-rule, against-the-rule, or oblique. Analysis of visual acuity and refractive outcomes was performed using American National Standards Institute (ANSI) guidelines on astigmatic corrections with non-vector as well as vector analyses. Analysis was limited to one eye per patient. Results: Patients who had with-the-rule (WTR) astigmatism, compared with oblique and against-the-rule (ATR), had higher vector magnitudes of surgically induced refractive correction (2.89D, 2.55D, 2.42D; p Conclusions: Refractive lens exchange surgery using toric intraocular lenses overcorrected patients who had with-the-rule astigmatism. Degree of overcorrection did not vary with severity of pre-operative astigmatism. Incorporation of axis of astigmatism in lens selection and reduction of astigmatic correction among with-the-rule patients by an absolute value of 0.25D - 0.35D, rather than proportional adjustments, may reduce cylindrical over-correction.