Reducing the incidence of clinically significant residual astigmatism with a low-cylinder IOL using the Barrett toric calculator
What:
Paper Presentation | Présentation d'article
When:
4:58 PM, Saturday 2 Jun 2018
(3 minutes)
Where:
How:
Authors: David B. Yan, Monica Lau
Author Disclosure Block: D.B. Yan: Employment/honoraria/consulting fees; Name of Commercial Company(s); Alcon Labratories. M. Lau: Employment/honoraria/consulting fees; Name of Commercial Company(s); Alcon Labratories.
Abstract Body:
Purpose: Determine the effect of the targeted amount of residual astigmatism on the incidence of clinically significant post-operative astigmatism when implanting a low-cylinder IOL using the Barrett toric calculator.
Study Design: Retrospective Study
Methods: A low-cylinder toric IOL (SN6AT2, ~0.68D at corneal plane) was implanted in 44 eyes of 36 patients using the Barrett toric calculator to plan residual astigmatism <0.5D, or <0.1D if the axis flips 90°. Patients were divided by amount of targeted residual astigmatism into two groups: 1) < 0.1D (n=24) and 2) 0.1D-0.5D (n=20). The residual astigmatism with a non-toric IOL was calculated using a novel vector analysis with an online tool to combine the refracted residual astigmatism with a cross-cylinder 90° from the measured axis of the toric IOL at 1-month postop.
Results: Refracted postop astigmatism with the toric IOL (0.37±0.34D) was significantly lower (p<0.001) than the astigmatism with a non-toric IOL calculated by vector analysis (0.83 ± 0.33D). Targeting <0.1D residual astigmatism on Barrett toric calculator resulted in significantly less postoperative astigmatism compared to targeting 0.1-0.5D (0.26±0.22D vs. 0.50±0.42D; p=0.02). There was also a significantly lower incidence of clinically significant postoperative astigmatism (≥0.75D) in the <0.1D targeted astigmatism group compared to the 0.1-0.5D targeted astigmatism group (4% vs. 25%, p=0.05). The refractive benefit of the toric IOL was 0.46±0.31D. Frequency analysis showed that 91% of patients had a positive refractive benefit from the toric IOL, with 80% ≥ 0.25D benefit and 61% ≥ 0.5D benefit.
Conclusions: Vector analysis is an effective tool to demonstrate the refractive benefit of a toric IOL when implanting low-cylinder toric IOLs using the Barrett Toric Calculator. Greater targeting accuracy of astigmatism management with a low-cylinder toric IOL resulted in a lower incidence of clinically significant post-operative astigmatism.
Author Disclosure Block: D.B. Yan: Employment/honoraria/consulting fees; Name of Commercial Company(s); Alcon Labratories. M. Lau: Employment/honoraria/consulting fees; Name of Commercial Company(s); Alcon Labratories.
Abstract Body:
Purpose: Determine the effect of the targeted amount of residual astigmatism on the incidence of clinically significant post-operative astigmatism when implanting a low-cylinder IOL using the Barrett toric calculator.
Study Design: Retrospective Study
Methods: A low-cylinder toric IOL (SN6AT2, ~0.68D at corneal plane) was implanted in 44 eyes of 36 patients using the Barrett toric calculator to plan residual astigmatism <0.5D, or <0.1D if the axis flips 90°. Patients were divided by amount of targeted residual astigmatism into two groups: 1) < 0.1D (n=24) and 2) 0.1D-0.5D (n=20). The residual astigmatism with a non-toric IOL was calculated using a novel vector analysis with an online tool to combine the refracted residual astigmatism with a cross-cylinder 90° from the measured axis of the toric IOL at 1-month postop.
Results: Refracted postop astigmatism with the toric IOL (0.37±0.34D) was significantly lower (p<0.001) than the astigmatism with a non-toric IOL calculated by vector analysis (0.83 ± 0.33D). Targeting <0.1D residual astigmatism on Barrett toric calculator resulted in significantly less postoperative astigmatism compared to targeting 0.1-0.5D (0.26±0.22D vs. 0.50±0.42D; p=0.02). There was also a significantly lower incidence of clinically significant postoperative astigmatism (≥0.75D) in the <0.1D targeted astigmatism group compared to the 0.1-0.5D targeted astigmatism group (4% vs. 25%, p=0.05). The refractive benefit of the toric IOL was 0.46±0.31D. Frequency analysis showed that 91% of patients had a positive refractive benefit from the toric IOL, with 80% ≥ 0.25D benefit and 61% ≥ 0.5D benefit.
Conclusions: Vector analysis is an effective tool to demonstrate the refractive benefit of a toric IOL when implanting low-cylinder toric IOLs using the Barrett Toric Calculator. Greater targeting accuracy of astigmatism management with a low-cylinder toric IOL resulted in a lower incidence of clinically significant post-operative astigmatism.
