Vector analysis investigation of toric intraocular lens with no deviation from the intended axis
Authors Kawahara A, Takayanagi Y
Received 14 August 2016
Accepted for publication 7 October 2016
Published 2 November 2016 Volume 2016:10 Pages 2199—2203
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Colin Mak
Peer reviewer comments 3
Editor who approved publication: Dr Scott Fraser
Atsushi Kawahara,1,2 Yoshinori Takayanagi1
1Takayanagi Clinic, Kushiro, 2Sapporo Kato Eye Clinic, Sapporo, Hokkaido, Japan
Aim: The aim of this research was to evaluate vector analysis after implantation of toric intraocular lenses (IOLs) without deviation from the intended axis.
Methods: The study included 18 eyes of 16 patients who underwent cataract surgery with the insertion of a toric implant (AcrySof IQ Toric). The postoperative IOL meridian placement completely corresponded to that planned. Using vector analysis, surgically induced astigmatism (SIA) was derived from the refractive outcome versus the predicted postoperative keratometric astigmatism and was compared with targeted induced astigmatism (TIA). The difference vector (DV) was derived by calculating the vector expression of the remaining astigmatic change.
Results: The mean postoperative remaining refractive astigmatism of 0.73±0.55 diopters (D) was achieved versus the mean target of 0.44±0.28 D. There was a difference of 0.29 D between the target and achieved values. The mean SIA value was 1.90±0.99 D compared with the mean TIA value of 2.00±0.85 D. The mean DV value was 0.87±0.56 D. The astigmatism correction index (SIA/TIA) was 0.95, which was near the ideal value of 1. The index of success (DV/TIA) was 0.44, which was far from the ideal value of 0.
Conclusion: The implantation of toric IOLs is an effective, predictable method for astigmatic correction. However, some remaining astigmatism is present even if toric IOLs are placed accurately.
Keywords: cataract surgery, astigmatism, toric intraocular lens, alpins method, toric calculator, remaining astigmatism
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