Ten Key Points to Optimize Surgical Correction of Astigmatism

  • Jean-Luc Febbraro
  • Douglas D. Koch
  • Hamza N. Khan
Chapter

Abstract

Preoperative measurements of corneal astigmatism need to be sufficiently accurate to reduce preexisting astigmatism to within 0.50 (multifocal IOLs)–0.75 D (monofocal IOLs). Our diagnostic tools include manual or autokeratometers, optical biometry, and, importantly, topography or tomography. A prerequisite condition to guarantee the quality of the measurements is a healthy cornea, without any surface irregularities caused by either deficient tear film or corneal pathology:
  • Corneal astigmatism can be identified with manual and autokeratometers in a repeatable manner. However, these instruments are insufficient because they only measure four points in the central 3 mm of the cornea and are unable to detect astigmatic asymmetries, irregularities, posterior corneal, nor lenticular astigmatism.

  • Optical biometry provides magnitude and axis measurements at various optical zones (1.65, 2.3, or 3.3 mm depending on the instrument) with variable numbers of points (6, 18, and 32).

  • Corneal topography has become a mandatory test prior to toric implantation as it allows for the detection of asymmetric and irregular astigmatism. Comparative studies between manual and automated keratometry, Placido-type topography, and simulated keratometry of Scheimpflug systems showed similar results in terms of anterior corneal magnitude, but axis differences were noted [1–3]. Corneal topographers may usually be considered as the final judge in terms of axis, pending verification of the image quality.

  • Total corneal astigmatism includes anterior and posterior components of the cylinder. Previous methods measured the anterior component only, whereas slit-scanning technology, optical coherence tomography, and Scheimpflug imaging systems allow for the measurement of both anterior and posterior astigmatism. These newer systems use true refractive indices to calculate the anterior and posterior corneal powers (1.376 for the cornea and 1.336 for the aqueous), instead of a standardized corneal refractive index of 1.3375 [4]. Accuracy is still suboptimal, but these devices hold the promise that they can be used to reliably measure posterior astigmatism and optimize the estimation of total corneal astigmatism.

References

  1. 1.
    Shirayama M, Wang L, Weikert MP, et al. Comparison of corneal powers obtained from 4 different devices. Am J Ophthalmol. 2009;148(4):528–35.CrossRefPubMedGoogle Scholar
  2. 2.
    Kobashi H, Kamiya K, Igarashi A, et al. Comparison of corneal power, corneal astigmatism, and axis location in normal eyes obtained from autokeratometer and a corneal topographer. J Cataract Refract Surg. 2012;38(4):648–54.CrossRefPubMedGoogle Scholar
  3. 3.
    Visser N, Berendschot TT, Verbakel F, et al. Comparability and repeatability of corneal astigmatism measurements using different measurement technologies. J Cataract Refract Surg. 2012;38(10):1764–70.CrossRefPubMedGoogle Scholar
  4. 4.
    Ventura B, Wang L, Weikert M, et al. Surgical management of astigmatism with toric intraocular lenses. Arq Bras Oftalmol. 2014;77(2):125–31.CrossRefPubMedGoogle Scholar
  5. 5.
    Mingo-Botin D, Munoz-Negrete FJ, Won Kim HR, et al. Comparison of toric intraocular lenses and peripheral corneal relaxing incisions to treat astigmatism during cataract surgery. J Cataract Refract Surg. 2010;36(10):1700–8.CrossRefPubMedGoogle Scholar
  6. 6.
    Cervantes-Coste G, Garcia-Ramirez L, Mendoza-Schuster E. at al. High-cylinder acrylic toric intraocular lenses : a case series of eyes with cataract and large amounts of corneal astigmatism. J Refract Surg. 2012;28(4):302–4.CrossRefPubMedGoogle Scholar
  7. 7.
    Hoffmann PC, Hutz WW. Analysis of biometry and prevalence data for corneal astigmatism in 23239 eyes. J Cataract Refract Surg. 2010;35(1):70–5.Google Scholar
  8. 8.
    Ferrar-Blasco T, Montès-Mico R, Peixoto-de-Matos SC, et al. Prevalence of astigmatism before cataract surgery. J Cataract Refract Surg. 2009;36(9):1479–85.Google Scholar
  9. 9.
    Nanavaty MA, Lake DB, Daya SM. Outcomes of pseudophakic toric intraocular lens implantation in keratoconic eyes with cataract. J Refract Surg. 2012;28(12):884–9.CrossRefPubMedGoogle Scholar
  10. 10.
    Lane SS, Ernest P, Miller KM, et al. Comparison of clinical and patient-reported outcomes with bilateral Acrysoft toric or spherical control intraocular lenses. J Refract Surg. 2009;25(10):899–901.CrossRefPubMedGoogle Scholar
  11. 11.
    Kohnen T, Dick B, Jacobi KW. Comparison of the induced astigmatism after clear corneal tunnel incisions of different sizes. J Cataract Refract Surg. 1995;21:417–24.CrossRefPubMedGoogle Scholar
  12. 12.
    Long DA, Long LM. A prospective evaluation of corneal curvature changes with 3.0- to 3.5-mm corneal tunnel phacoemulsification. Ophthalmology. 1996;103:226–32.CrossRefPubMedGoogle Scholar
  13. 13.
    Kohnen T. Corneal shape changes and astigmatic aspects of scleral and corneal tunnel incisions (editorial). J Cataract Refract Surg. 1997;23:301–2.CrossRefPubMedGoogle Scholar
  14. 14.
    Kohnen S, Neuber R, Kohnen T. Effects of temporal and nasal unsutured limbal tunnel incisions on induced astigmatism after phacoemulsification incisions. J Cataract Refract Surg. 2002;28:821–5.CrossRefPubMedGoogle Scholar
  15. 15.
    Borasio E, Mehta J, Maurino V. Surgically induced astigmatism after phacoemulsification in eyes with mild to moderate corneal astigmatism: temporal versus on-axis clear corneal incisions. J Cataract Refract Surg. 2006;32:565–6572.CrossRefPubMedGoogle Scholar
  16. 16.
    Koch DD. How should we analyze astigmatic data? (editorial). J Cataract Refract Surg. 2001;27:1–3.CrossRefPubMedGoogle Scholar
  17. 17.
    Holladay JT, Cravy TV, Koch DD. Calculating the surgically induced refractive change following ocular surgery. J Cataract Refract Surg. 1992;18:429–43.CrossRefPubMedGoogle Scholar
  18. 18.
    Alpins NA. A new method of analyzing vectors for changes in astigmatism. J Cataract Refract Surg. 1993;19:524–33.CrossRefPubMedGoogle Scholar
  19. 19.
    Javal E. Mémoires d’ophtalmométrie: Annotés et précédés d’une introduction. Paris: G. Masson; 1890. p. 131.Google Scholar
  20. 20.
    Koch DD, Shazia FA, Weickert MP, et al. Contribution of posterior corneal astigmatism to total corneal astigmatism. J Cataract Refract Surg. 2012;38:2080–7.CrossRefPubMedGoogle Scholar
  21. 21.
    Abulafia A, Koch DD, Wang L, et al. New regression formula for toric intraocular lens calculations. J Cataract Refract Surg. 2016;42:663–71.CrossRefPubMedGoogle Scholar
  22. 22.
    Koch DD, Weickert MP, YEU E, et al. Correcting astigmatism with toric intraocular lenses : The effect of posterior corneal astigmatism. J Cataract Refract Surg. 2013;39(12):1803–9.CrossRefPubMedGoogle Scholar
  23. 23.
    Davson H. Physiology of the eye. 2nd ed. Boston: Little, Brown; 1963. p. 227.Google Scholar
  24. 24.
    Sanders DR, Sarver EJ, Cooke DL. Accuracy and precision of a new system for measuring toric intraocular lens rotation. J Cataract Refract Surg. 2013;39:1190–5.CrossRefPubMedGoogle Scholar
  25. 25.
    Igarashi A, Kamiya K, Shimizu K. Clinical evaluation of accuracy of horizontal meridian limbal marking. Optom Vis Sci. 2013;90:540–5.CrossRefPubMedGoogle Scholar
  26. 26.
    Febbraro JL, Koch DD, Khan H, et al. Detection of static and compensation for dynamic cyclotorsion in laser in situ keratomileusis. J Cataract Refract Surg. 2010;36(10):1718–23.CrossRefPubMedGoogle Scholar
  27. 27.
    Popp N, Hirnshall N, Maedel S, et al. Evaluation of 4 corneal astigmatic marking methods. J Cataract Refract Surg. 2012;38(12):2094–9.CrossRefPubMedGoogle Scholar
  28. 28.
    Osher RH. Iris fingerprinting new method for improving accuracy in toric lens orientation. J Cataract Refract Surg. 2010;36(2):351–2.CrossRefPubMedGoogle Scholar
  29. 29.
    Montes de Oca I, Kim E, Wang L, Weikert MP, Khandelwal SS, Al-Mohtaseb Z, Koch DD. Accuracy of toric intraocular lens axis alignment using a 3D computer-guided visualization system. J Cataract Refract Surg. 2016 Apr;42(4):550–5.CrossRefPubMedGoogle Scholar
  30. 30.
    Lans LJ. Experimentelle untersuchungen uber die entstehung von astigmatism durch nicht-perforierende corneawunden. Graefes Arch Clin Exp Ophthalmol. 1888;45:117–52.CrossRefGoogle Scholar
  31. 31.
    Thornton SP. Astigmatic keratotomy : a review of basic concepts with case reports. J Cataract Refract Surg. 1990;16:430–5.CrossRefPubMedGoogle Scholar
  32. 32.
    Gills JP. Reducing pre-existing astigmatism. In: Gills JP, editor. Cataract surgery: The state of the art. Thorofare: SLACK; 1998. p. 53–66.Google Scholar
  33. 33.
    Lombardo A, Linsdtrom R. Astigmatic keratotomy : Arcuate and transverse incisions for managing astigmatism. In: Gills JP, editor. A complete surgical guide for correcting astigmatism. Thorofare: SLACK; 2003. p. 87–96.Google Scholar
  34. 34.
    Budak K, Friedman NJ, Koch DD. Limbal relaxing incisions with cataract surgery. J Cataract Refract Surg. 1998;24:503–8.CrossRefPubMedGoogle Scholar
  35. 35.
    Venter J, Blumenfeld R, Schalhorn S, et al. Non-penetrating femtosecond laser intrastromal astigmatic keratotomy in patients with mixed astigmatism after previous refractive surgery. J Refract Surg. 2013;29:180–6.CrossRefPubMedGoogle Scholar
  36. 36.
    Chan TCY, Cheng GPM, Wang Z, et al. Vector analysis of corneal astigmatism after combined femtosecond-assisted phacoemulsification and arcuate keratotomy. Am J Ophthalmol. 2015;160:250–5.CrossRefPubMedGoogle Scholar
  37. 37.
    Day AC, Lau NM, Stevens JD. Non-penetrating femtosecond laser intrastromal astigmatic keratotomy in eyes having cataract surgery. J Cataract Refract Surg. 2016;42:102–9.CrossRefPubMedGoogle Scholar
  38. 38.
    Day AC, Stevens JD. Predictors of femtosecond laser intrastromal astigmatic keratotomy efficacy for astigmatism management cataract surgery. J Cataract Refract Surg. 2016;42:102–9.CrossRefPubMedGoogle Scholar
  39. 39.
    Day AC, Stevens JD. Stability of keratometric astigmatism after non-penetrating femtosecond laser intrastromal astigmatic keratotomy performed during laser cataract surgery. J Refract Surg. 2016;42:251–7.CrossRefGoogle Scholar
  40. 40.
    Shimizu K, Misawa A, Suzuki Y. Toric intraocular lenses: correcting astigmatism while controlling axis shift. J Cataract Refract Surg. 1994;20:523.CrossRefPubMedGoogle Scholar
  41. 41.
    Grabow HB. Early results with foldable toric IOL implantation. Eur J Implant Refract Surg. 1994;6:177–8.Google Scholar
  42. 42.
    Grabow HB. Toric intraocular lens report. Ann Ophthalmol Glaucoma. 1997;29:161–3.Google Scholar
  43. 43.
    Sun X-Y, Vicary D, Montgomery P, Griffiths M. Toric intraocular lenses for correcting astigmatism in 130 eyes. Ophthalmology. 2000;107:1776–81; discussion by RM Kershner, 1781–2CrossRefPubMedGoogle Scholar
  44. 44.
    Ruhswurm I, Scholz U, Zehetmayer M, Hanselmayer G, Vass C, Skorpik C. Astigmatism correction with a foldable toric intraocular lens in cataract patients. J Cataract Refract Surg. 2000;26:1022–7.CrossRefPubMedGoogle Scholar
  45. 45.
    Patel CK, Ormonde S, Rosen PH, Bron AJ. Postoperative intra-ocular lens rotation: a randomized comparison of plate and loop haptic implants. Ophthalmology. 1999;106:2190–5; discussion by DJ Apple, 2196CrossRefPubMedGoogle Scholar
  46. 46.
    Kim HM, Chung T-Y, Chung E-S. Long-term efficacy and rotational stability of AcrySof toric intraocular lens implantation in cataract surgery. Korean J Ophthalmol. 2010;24(4):207–12.CrossRefPubMedPubMedCentralGoogle Scholar
  47. 47.
    Koshy JJ, et al. Rotational stability of a single-piece toric acrylic intraocular lens. J Cataract Refract Surg. 2010;36(10):1665–70.CrossRefPubMedGoogle Scholar
  48. 48.
    Chang DV. Early rotational stability of the longer Staar toric intraocular lens; fifty consecutive cases. J Cataract Refract Surg. 2003;29:935–40.CrossRefPubMedGoogle Scholar
  49. 49.
    Shah GD, Praveen MR, Vasavada AR, Vasavada VA, Rampal G, Shastry LR. Rotational stability of a toric intraocular lens: influence of axial length and alignment in the capsular bag. J Cataract Refract Surg. 2012;38:54–9.CrossRefPubMedGoogle Scholar
  50. 50.
    Prinz A, Neumayer T, Buehl W, Vock L, Menapace R, Findl O, Georgopoulos M. Rotational stability and posterior capsule opacification of a plate-haptic and an open-loop-haptic intraocular lens. J Cataract Refract Surg. 2011;37:251–7.CrossRefPubMedGoogle Scholar
  51. 51.
    Visser N, Bauer N, Nuijts R. Toric intraocular lenses: historical overview, patient selection, IOL calculation, surgical techniques, clinical outcomes, and complications. J Cataract Refract Surg. 2013;39:624–37.CrossRefPubMedGoogle Scholar
  52. 52.
    Felipe A, Artigas JM, Diez-Ajenjo A, et al. Residual astigmatism produced by toric intraocular lens rotation. J Cataract Refract Surg. 2011;37:1895–901.CrossRefPubMedGoogle Scholar
  53. 53.
    Visser N, Berendschot T, Bauer N, et al. Accuracy of toric intraocular lens implantation in cataract and refractive surgery. J Cataract Refract Surg. 2011;37:1394–402.CrossRefPubMedGoogle Scholar
  54. 54.
    http://astigmatismfix.com/ Accessed October 30, 2016.

Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  • Jean-Luc Febbraro
    • 1
  • Douglas D. Koch
    • 2
  • Hamza N. Khan
    • 3
  1. 1.Rothschild FoundationParisFrance
  2. 2.Cullen Eye Institute, Baylor College of MedicineHoustonUSA
  3. 3.University of British ColumbiaVictoriaCanada

Personalised recommendations