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Toric intraocular lens orientation and residual refractive astigmatism: an analysis

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: To analyze intraocular lens (IOL) orientation data from an online toric back-calculator (astigmatismfix.com) for determining if differences were apparent by lens type.

Methods: A retrospective review of astigmatismfix.com toric back-calculations that included IOL identification and intended orientation axis.

Results: Of 12,812 total validated calculation records, 8,229 included intended orientation and lens identification data. Of the latter, 5,674 calculations (69%) involved lenses oriented 5° or more from their intended position. Using estimated toric lens usage data, the percentage of lenses with orientation ≥5° from intended was 0.89% overall, but the percentage varied significantly between specific toric lens brands (P<0.05). The percentage of back-calculations related to lenses that were not oriented as intended was also statistically significantly different by lens brand (P<0.05). When IOLs were misoriented, they were significantly more likely to be misoriented in a counterclockwise direction (P<0.05). This was found to be due to a bias toward counterclockwise orientation observed with one specific brand, a bias that was not observed with the other three brands analyzed here.

Conclusion: The percentage of eyes with lens orientation ≥5° from intended in the Toric Results Analyzer data set was <1% of toric IOLs in general, with the relative percentage of Tecnis® Toric IOLs significantly higher than AcrySof® Toric IOLs. Both of these had higher rates than the Staar® Toric and Trulign® Toric lenses, with the availability of higher Tecnis and AcrySof cylinder powers a likely contributing factor. The AcrySof Toric IOL appears to be less likely than the Tecnis Toric IOL to cause residual astigmatism as a result of misorientation. The Tecnis Toric IOL appears more likely to be misoriented in a counterclockwise direction; no such bias was observed with the AcrySof Toric, the Trulign® Toric, or the Staar Toric IOLs.

No MeSH data available.


Related in: MedlinePlus

Lens misorientation by group and direction.Notes: *Likelihood results are equally distributed around zero. Group A, AcrySof® Toric (Alcon Laboratories, Inc, Fort Worth, TX, USA); group T, Tecnis® Toric (Abbott Medical Optics Inc., Santa Ana, CA, USA); group S, Staar® Toric (Staar Surgical Company, Monrovia, CA, USA); and group B, Trulign® Toric (Bausch & Lomb Surgical, Inc., Rancho Cucamonga, USA). Statistically significant values are shown in bold (P<0.05).Abbreviations: CCW, counterclockwise; CW, clockwise; IOL, intraocular lens.
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f3-opth-10-1829: Lens misorientation by group and direction.Notes: *Likelihood results are equally distributed around zero. Group A, AcrySof® Toric (Alcon Laboratories, Inc, Fort Worth, TX, USA); group T, Tecnis® Toric (Abbott Medical Optics Inc., Santa Ana, CA, USA); group S, Staar® Toric (Staar Surgical Company, Monrovia, CA, USA); and group B, Trulign® Toric (Bausch & Lomb Surgical, Inc., Rancho Cucamonga, USA). Statistically significant values are shown in bold (P<0.05).Abbreviations: CCW, counterclockwise; CW, clockwise; IOL, intraocular lens.

Mentions: Direction of orientation was also of interest; this could be determined from the sign of the angle difference between the intended and actual orientation, as it was presumed that lenses rotated or were misaligned by <90°. Figure 3 shows the percentage of eyes by IOL group that were clockwise and counterclockwise of the intended orientation. Only group T demonstrated any statistically significant bias, with a higher percentage of lenses oriented counterclockwise from the intended direction (P<0.001, chi-square test, 95% confidence interval of the odds ratio [1.65, 2.13]).


Toric intraocular lens orientation and residual refractive astigmatism: an analysis
Lens misorientation by group and direction.Notes: *Likelihood results are equally distributed around zero. Group A, AcrySof® Toric (Alcon Laboratories, Inc, Fort Worth, TX, USA); group T, Tecnis® Toric (Abbott Medical Optics Inc., Santa Ana, CA, USA); group S, Staar® Toric (Staar Surgical Company, Monrovia, CA, USA); and group B, Trulign® Toric (Bausch & Lomb Surgical, Inc., Rancho Cucamonga, USA). Statistically significant values are shown in bold (P<0.05).Abbreviations: CCW, counterclockwise; CW, clockwise; IOL, intraocular lens.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036610&req=5

f3-opth-10-1829: Lens misorientation by group and direction.Notes: *Likelihood results are equally distributed around zero. Group A, AcrySof® Toric (Alcon Laboratories, Inc, Fort Worth, TX, USA); group T, Tecnis® Toric (Abbott Medical Optics Inc., Santa Ana, CA, USA); group S, Staar® Toric (Staar Surgical Company, Monrovia, CA, USA); and group B, Trulign® Toric (Bausch & Lomb Surgical, Inc., Rancho Cucamonga, USA). Statistically significant values are shown in bold (P<0.05).Abbreviations: CCW, counterclockwise; CW, clockwise; IOL, intraocular lens.
Mentions: Direction of orientation was also of interest; this could be determined from the sign of the angle difference between the intended and actual orientation, as it was presumed that lenses rotated or were misaligned by <90°. Figure 3 shows the percentage of eyes by IOL group that were clockwise and counterclockwise of the intended orientation. Only group T demonstrated any statistically significant bias, with a higher percentage of lenses oriented counterclockwise from the intended direction (P<0.001, chi-square test, 95% confidence interval of the odds ratio [1.65, 2.13]).

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: To analyze intraocular lens (IOL) orientation data from an online toric back-calculator (astigmatismfix.com) for determining if differences were apparent by lens type.

Methods: A retrospective review of astigmatismfix.com toric back-calculations that included IOL identification and intended orientation axis.

Results: Of 12,812 total validated calculation records, 8,229 included intended orientation and lens identification data. Of the latter, 5,674 calculations (69%) involved lenses oriented 5&deg; or more from their intended position. Using estimated toric lens usage data, the percentage of lenses with orientation &ge;5&deg; from intended was 0.89% overall, but the percentage varied significantly between specific toric lens brands (P&lt;0.05). The percentage of back-calculations related to lenses that were not oriented as intended was also statistically significantly different by lens brand (P&lt;0.05). When IOLs were misoriented, they were significantly more likely to be misoriented in a counterclockwise direction (P&lt;0.05). This was found to be due to a bias toward counterclockwise orientation observed with one specific brand, a bias that was not observed with the other three brands analyzed here.

Conclusion: The percentage of eyes with lens orientation &ge;5&deg; from intended in the Toric Results Analyzer data set was &lt;1% of toric IOLs in general, with the relative percentage of Tecnis&reg; Toric IOLs significantly higher than AcrySof&reg; Toric IOLs. Both of these had higher rates than the Staar&reg; Toric and Trulign&reg; Toric lenses, with the availability of higher Tecnis and AcrySof cylinder powers a likely contributing factor. The AcrySof Toric IOL appears to be less likely than the Tecnis Toric IOL to cause residual astigmatism as a result of misorientation. The Tecnis Toric IOL appears more likely to be misoriented in a counterclockwise direction; no such bias was observed with the AcrySof Toric, the Trulign&reg; Toric, or the Staar Toric IOLs.

No MeSH data available.


Related in: MedlinePlus