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Performance of the Barrett Toric Calculator with and without measurements of posterior corneal curvature

Abstract

Background

Toric intraocular lens power calculators, e.g., the Barrett Toric Calculator, based on predicted, rather than on measured posterior corneal curvature have yielded the best results so far. However, recent update of the Barrett Toric Calculator aims to fine tune its refractive predictions with the input of measured posterior corneal curvature. Here, we wanted to compare refractive predictions of the Barrett Toric Calculator, based on IOL Master 700 biometry, with and without measurements of posterior corneal curvature.

Methods

In total 30 eyes were included in the study. One-month postoperative manifest refraction and predicted residual refractive error of both formulas were utilized to calculate mean absolute error and centroid error in predicted residual astigmatism. The Pentacam was used to measure posterior corneal curvature.

Results

We did not find any statistically significant difference in mean absolute error and centroid error in predicted residual astigmatism between the Barrett Toric Calculator with and without measurement of posterior corneal curvature. Post-hoc analysis of with-the-rule and against-the-rule astigmatic eyes did not reveal any significant differences as well.

Conclusions

Astigmatism prediction errors, based on IOL Master 700 biometry, with and without measured posterior corneal curvature, were similar. To the best of our knowledge, the updated Barrett Toric Calculator is the first formula to provide non-inferior and reliable predictions based on measurement of posterior corneal curvature.

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References

  1. 1.

    Olsen T. Calculation of intraocular lens power: a review. Acta Ophthalmol Scand. 2007;85:472–85.

  2. 2.

    Cooke DL, Cooke TL. Comparison of 9 intraocular lens power calculation formulas. J Cataract Refract Surg. 2016;42:1157–64.

  3. 3.

    Roberts TV, Hodge C, Sutton G, Lawless M, contributors to the Vision Eye Institute IOLor. Comparison of Hill-radial basis function, Barrett Universal and current third generation formulas for the calculation of intraocular lens power during cataract surgery. Clin Exp Ophthalmol. 2018;46:240–6.

  4. 4.

    Koch DD, Hill W, Abulafia A, Wang L. Pursuing perfection in intraocular lens calculations: I. Logical approach for classifying IOL calculation formulas. J Cataract Refract Surg. 2017;43:717–8.

  5. 5.

    Visser N, Beckers HJ, Bauer NJ, Gast ST, Zijlmans BL, Berenschot TT, et al. Toric vs aspherical control intraocular lenses in patients with cataract and corneal astigmatism: a randomized clinical trial. JAMA Ophthalmol. 2014;132:1462–8.

  6. 6.

    Reitblat O, Levy A, Kleinmann G, Abulafia A, Assia EI. Effect of posterior corneal astigmatism on power calculation and alignment of toric intraocular lenses: comparison of methodologies. J Cataract Refract Surg. 2016;42:217–25.

  7. 7.

    Koch DD. The posterior cornea: hiding in plain sight. Ophthalmology. 2015;122:1070–1.

  8. 8.

    Koch DD, Ali SF, Weikert MP, Shirayama M, Jenkins R, Wang L. Contribution of posterior corneal astigmatism to total corneal astigmatism. J Cataract Refract Surg. 2012;38:2080–7.

  9. 9.

    Koch DD, Jenkins RB, Weikert MP, Yeu E, Wang L. Correcting astigmatism with toric intraocular lenses: effect of posterior corneal astigmatism. J Cataract Refract Surg. 2013;39:1803–9.

  10. 10.

    Hoffmann PC, Wahl J, Hutz WW, Preussner PR. A ray tracing approach to calculate toric intraocular lenses. J Refract Surg. 2013;29:402–8.

  11. 11.

    Preussner PR, Hoffmann P, Wahl J. Impact of posterior corneal surface on toric intraocular lens (IOL) calculation. Curr Eye Res. 2015;40:809–14.

  12. 12.

    Abulafia A, Barrett GD, Kleinmann G, Ofir S, Levy A, Marcovich AL, et al. Prediction of refractive outcomes with toric intraocular lens implantation. J Cataract Refract Surg. 2015;41:936–44.

  13. 13.

    http://www.ascrs.org/barrett-toric-calculator. Accessed 15.01.2018.

  14. 14.

    Abulafia A, Koch DD, Wang L, Hill WE, Assia EI, Franchina M, et al. New regression formula for toric intraocular lens calculations. J Cataract Refract Surg. 2016;42:663–71.

  15. 15.

    Hoffmann PC, Abraham M, Hirnschall N, Findl O. Prediction of residual astigmatism after cataract surgery using swept source fourier domain optical coherence tomography. Curr Eye Res. 2014;39:1178–86.

  16. 16.

    Holladay JT, Moran JR, Kezirian GM. Analysis of aggregate surgically induced refractive change, prediction error, and intraocular astigmatism. J Cataract Refract Surg. 2001;27:61–79.

  17. 17.

    Dang MS, Raj PP. SRK II formula in the calculation of intraocular lens power. Br J Ophthalmol. 1989;73:823–6.

  18. 18.

    Visser N, Bauer NJ, Nuijts RM. Toric intraocular lenses: historical overview, patient selection, IOL calculation, surgical techniques, clinical outcomes, and complications. J Cataract Refract Surg. 2013;39:624–37.

  19. 19.

    Sun XY, Vicary D, Montgomery P, Griffiths M. Toric intraocular lenses for correcting astigmatism in 130 eyes. Ophthalmology. 2000;107:1776–81. discussion 1781–1772.

  20. 20.

    Abulafia A, Hill WE, Franchina M, Barrett GD. Comparison of methods to predict residual astigmatism after intraocular lens implantation. J Refract Surg. 2015;31:699–707.

  21. 21.

    Ferreira TB, Ribeiro P, Ribeiro FJ, O’Neill JG. Comparison of astigmatic prediction errors associated with new calculation methods for toric intraocular lenses. J Cataract Refract Surg. 2017;43:340–7.

  22. 22.

    Ferreira TB, Ribeiro P, Ribeiro FJ, O’Neill JG. Comparison of methodologies using estimated or measured values of total corneal astigmatism for toric intraocular lens power calculation. J Refract Surg. 2017;33:794–800.

  23. 23.

    Thebpatiphat N, Hammersmith KM, Rapuano CJ, Ayres BD, Cohen EJ. Cataract surgery in keratoconus. Eye Contact Lens. 2007;33:244–6.

  24. 24.

    Masket S, Wang L, Belani S. Induced astigmatism with 2.2- and 3.0-mm coaxial phacoemulsification incisions. J Refract Surg. 2009;25:21–24.

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Correspondence to Leejee H. Suh.

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