Myopia and myopic astigmatism photorefractive keratectomy: applying an advanced multiple regression-derived nomogram

  • Yinon ShapiraEmail author
  • Igor Vainer
  • Michael Mimouni
  • Tzahi Sela
  • Gur Munzer
  • Igor Kaiserman
Refractive Surgery



To evaluate a multiple regression-derived nomogram for myopia and myopic astigmatism photorefractive keratectomy (PRK).


Regression modeling derived a formula for spherocylindrical correction in wavefront-optimized PRK (nomogram II). Treatment outcomes between eyes with myopia and myopic astigmatism using the manufacturer’s nomogram (nomogram I) in the years 2010–2013 were retrospectively compared with eyes treated using nomogram II in the years 2014–2015.


Overall 1100 eyes (of 561 patients) were operated using nomogram I and 791 eyes (of 406 patients) using nomogram II. Nomogram II achieved correction within ± 0.5 D of the attempted in 90% (95% CI 86.8–92.3%) of eyes with a spherical equivalent (SE) < |− 6|D, compared to 84% (95% CI 81.8–86.9%) in nomogram I. Overcorrection was reached in 14% (95% CI 10.1–18.3%) of eyes with SE ≥ |-6|D in nomogram II, compared to 22.6% (95% CI 18.1–27.2%) in nomogram I. Nomogram II achieved correction within ± 0.5 D of the attempted in 88.7% (95% CI 85.7–91.6%) of patients aged 18–23 years compared to 81.2% (95% CI 77.9–84.5%) in nomogram I; however, in 77% (95% CI 69.5–84.4%) versus 87.4% (95% CI 82.7–92.0%), respectively, among patients aged ≥ 30 years. In eyes with astigmatism ≥ 2 D, a postoperative astigmatism < 0.5 D was achieved in 89.4% (95% CI 83.0–95.7%) versus 72.9% (95% CI 64.3–81.5%), and a treatment efficacy index ≥ 0.9 was achieved in 100% versus 92.6% (95% CI 87.6–97.6%) with nomogram II versus nomogram I, respectively.


There were several clinically significant benefits of the advanced nomogram in wavefront-optimized myopia PRK. On the other hand, there was a trend of lower accuracy in the older age group, warranting a second iteration.


Nomogram PRK Refractive surgery Regression analysis Accuracy Outcome 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the Barzilai Medical Center institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required.

Supplementary material

417_2018_4101_MOESM1_ESM.docx (41 kb)
ESM 1 (DOCX 40 kb)


  1. 1.
    Hersh PS, Brint SF, Maloney RK et al (1998) Photorefractive keratectomy versus laser in situ keratomileusis for moderate to high myopia. A randomized prospective study. Ophthalmology 105:1512–1523CrossRefGoogle Scholar
  2. 2.
    Allan BD, Hassan H, Ieong A (2015) Multiple regression analysis in nomogram development for myopic wavefront laser in situ keratomileusis: improving astigmatic outcomes. J Cataract Refract Surg 41:1009–1017CrossRefGoogle Scholar
  3. 3.
    Liyanage SE, Allan BD (2012) Multiple regression analysis in myopic wavefront laser in situ keratomileusis nomogram development. J Cataract Refract Surg 38:1232–1239CrossRefGoogle Scholar
  4. 4.
    Mimouni M, Vainer I, Shapira Y et al (2016) Factors predicting the need for retreatment after laser refractive surgery. Cornea 35:607–612CrossRefGoogle Scholar
  5. 5.
    Shapira Y, Vainer I, Mimouni M et al (2016) Effect of anisometropia on the predictability and accuracy of refractive surgery. Cornea 35:1410–1415CrossRefGoogle Scholar
  6. 6.
    Shapira Y, Mimouni M, Levartovsky SC et al (2015) Comparison of three epithelial removal techniques in PRK: mechanical, alcohol assisted, and transepithelial laser. J Refract Surg 31:760–766CrossRefGoogle Scholar
  7. 7.
    Mohammadpour M, Hashemi H, Jabbarvand M, Rahmatnejad KSF (2016) Efficacy of wavefront-guided photorefractive keratectomy with iris registration for management of moderate to high astigmatism by advanced personalized treatment nomograme. J Ophthalmic Vis Res 11:136–140CrossRefGoogle Scholar
  8. 8.
    Lapid-Gortzak R, van der Linden JW, van der Meulen IJE, Nieuwendaal CP (2008) Advanced personalized nomogram for myopic laser surgery: first 100 eyes. J Cataract Refract Surg 34:1881–1885CrossRefGoogle Scholar
  9. 9.
    Subbaram MV, MacRae SM (2007) Customized LASIK treatment for myopia based on preoperative manifest refraction and higher order aberrometry: the Rochester nomogram. J Refract Surg 23:435–441CrossRefGoogle Scholar
  10. 10.
    Thibos LN, Wheeler W, Horner D (1997) Power vectors: an application of Fourier analysis to the description and statistical analysis of refractive error. Optom Vis Sci 74:367–375CrossRefGoogle Scholar
  11. 11.
    Han DC, Chen J, Htoon HM et al (2012) Comparison of outcomes of conventional WaveLight((R)) Allegretto Wave((R)) and Technolas((R)) excimer lasers in myopic laser in situ keratomileusis. Clin Ophthalmol 6:1159–1168Google Scholar
  12. 12.
    Caster AI, Hoff JL, Ruiz R (2004) Nomogram adjustment of laser in situ keratomileusis for myopia and myopic astigmatism with the Alcon LADARVision system. J Refract Surg 20:364–370Google Scholar
  13. 13.
    Ditzen K, Handzel A, Pieger S (1999) Laser in situ keratomileusis nomogram development. J Refract Surg 15:S197–S201Google Scholar
  14. 14.
    Mohammadpour M, Hashemi H, Jabbarvand M, Rahmatnejad KSF (2016) Efficacy of wavefront-guided photorefractive keratectomy with Iris registration for management of moderate to high astigmatism by advanced personalized treatment nomogram. J Ophthalmic Vis Res 11:136–140CrossRefGoogle Scholar
  15. 15.
    Subbaram MV, MacRae SM (2006) Does dilated wavefront aberration measurement provide better postoperative outcome after custom LASIK? Ophthalmology 113:1813–1817CrossRefGoogle Scholar
  16. 16.
    Arnalich-Montiel F, Wilson CM, Morton SJ, Allan BD (2009) Back-calculation to model strategies for pretreatment adjustment of the ablation sphere in myopic wavefront laser in situ keratomileusis. J Cataract Refract Surg 35:1174–1180CrossRefGoogle Scholar
  17. 17.
    Labiris G, Sideroudi H, Giarmoukakis A, Koukoula S, Pagonis GKV (2012) Evaluation of the difference between intended and measured ablation and its impact on refractive outcomes of the wavefront optimize profile and the S001 Wellington nomogram in myopic spherocylindrical corrections. Clin Exp Ophthalmol 40:127–133CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Yinon Shapira
    • 1
    Email author
  • Igor Vainer
    • 1
  • Michael Mimouni
    • 1
  • Tzahi Sela
    • 2
  • Gur Munzer
    • 2
  • Igor Kaiserman
    • 2
    • 3
  1. 1.Department of OphthalmologyRambam Health Care Campus and the Technion Israel Institute of TechnologyHaifaIsrael
  2. 2.Care-Vision Laser CentersTel-AvivIsrael
  3. 3.Department of Ophthalmology, Barzilai Medical Center, Ashkelon and the Faculty of Health SciencesBen-Gurion University of the NegevBeer ShebaIsrael

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