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Biomechanics and Modeling in Mechanobiology

, Volume 17, Issue 4, pp 923–938 | Cite as

Template-based methodology for the simulation of intracorneal segment ring implantation in human corneas

  • Julio Flecha-Lescún
  • Begoña Calvo
  • Jesús Zurita
  • Miguel Ángel Ariza-Gracia
Review Paper
  • 130 Downloads

Abstract

Keratoconus is an idiopathic, non-inflammatory and degenerative corneal disease characterised by a loss of the organisation in the corneal collagen fibrils. As a result, keratoconic corneas present a localised thinning and conical protrusion with irregular astigmatism and high myopia that worsen visual acuity. Intracorneal ring segments (ICRSs) are used in clinic to regularise the corneal surface and to prevent the disease from progressing. Unfortunately, the post-surgical effect of the ICRS is not explicitly accounted beforehand. Traditional treatments rely on population-based nomograms and the experience of the surgeon. In this vein, in silico models could be a clinical aid tool for clinicians to plan the intervention, or to test the post-surgical impact of different clinical scenarios. A semi-automatic computational methodology is presented in order to simulate the ICRS surgical operation and to predict the post-surgical optical outcomes. For the sake of simplicity, circular cross section rings, average corneas and an isotropic hyperelastic material are used. To determine whether the model behaves physiologically and to carry out a sensitivity analysis, a \(3^k\) full-factorial analysis is carried out. In particular, how the stromal depth insertion, horizontal distance of ring insertion (hDRI) and diameter of the ring’s cross section (\(\phi _\mathrm{ICRS}\)) are impacting in the spherical and cylindrical power of the cornea is analysed. Afterwards, the kinematics, mechanics and optics of keratoconic corneas after the ICRS insertion are analysed. Based on the parametric study, we can conclude that our model follows clinical trends previously reported. In particular and although there is an improvement in defocus, all corneas presented a change in their optical aberrations. The stromal depth insertion is the parameter that affects the corneal optics the most, whereas hDRI and \(\phi _\mathrm{ICRS}\) are less important. Not only that, but it is almost impossible to achieve an optimal trade-off between spherical and cylindrical correction. Regarding the mechanical behaviour, inserting the rings at 65% depth or above will cause the cornea to slightly bend. This abnormal stress distribution greatly distorts the corneal optics and, more importantly, could be the cause of clinical problems such as corneal extrusion. Not only that, but our model also supports that rings are acting as restraint elements which relax the stresses of the corneal stroma in the cone of the disease. However, depending on the exact spatial location of the keratoconus, the insertion of rings could promote its evolution instead of preventing it. ICRS inserted deeper will prevent keratoconus in the posterior stroma from growing (relaxation of posterior surface), but will promote its growing if they are located in the anterior surface (increment of stress). In conclusion, the methodology proposed is suitable for simulating long-term mechanical and optical effects of ICRS insertion.

Keywords

Corneal biomechanics Template-based automatisation Keratoconus Intracorneal segment ring Corneal ectasia Finite element methodology 

Notes

Funding

This work was supported by the Spanish Ministry of Economy and Competitiveness (Projects DPI2014-54981-R and DPI2017-84047-R), Department of Industry and Innovation (Government of Aragón) and European Social Fund 2014-2020 (FSE-DGA T88). J. Flecha was supported by the Spanish Ministry of Economy and Competitiveness (BES-2015-073630). M.Á. Ariza-Gracia was supported by the Swiss Government through the ESKAS program (ESKAS-No: 2016.0194. Federal Commission for Scholarships for Foreign Students FCS, Switzerland).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

Supplementary material 1 (mp4 14963 KB)

References

  1. Abdelmassih Y, El Khoury S, Chelala E, Slim E, Cherfan CG, Jarade E (2017) Toric ICL implantation after sequential intracorneal ring segments implantation and corneal cross-linking in keratoconus: 2-year follow-up. J Refract Surg 33(9):610–616.  https://doi.org/10.3928/1081597X-20170621-02 CrossRefGoogle Scholar
  2. Alió JL, Artola A, Jassanein A, Haroun A, Galal A (2005) One or 2 intacs segments for the correction of keratoconus. J Cataract Refract Surg 31:943–953CrossRefGoogle Scholar
  3. Alió JL, Shabayek MH, Artola A (2006) Intracorneal ring segments for keratoconus correction: long-term follow-up. J Cataract Refract Surg 32:978–985CrossRefGoogle Scholar
  4. Akaishi L, Tzelikis PF, Raber IM (2004) Ferrara intracorneal ring implantation and cataract surgery for the correction of pellucid marginal corneal degeneration. J Cataract Refract Surg 30(11):2427–2430.  https://doi.org/10.1016/j.jcrs.2004.04.047 CrossRefGoogle Scholar
  5. Ariza-Gracia MÁ, Zurita J, Piñero DP, Rodríguez-Matas JF, Calvo B (2015) Coupled biomechanical response of the cornea assessed by non-contact tonometry. A simulation study. PlosOne 10(3):1–10CrossRefGoogle Scholar
  6. Ariza-Gracia MÁ, Zurita J, Piñero DP, Calvo B, Rodríguez-Matas JF (2016) Automatized patient-specific methodology for numerical determination of biomechanical corneal response. Ann Biomed Eng 44(5):1753–1772.  https://doi.org/10.1007/s10439-015-1426-0 CrossRefGoogle Scholar
  7. Ariza-Gracia MÁ, Ortillés A, Cristóbal J, Rodríguez-Matas JF, Calvo B (2017) A numerical-experimental protocol to characterize corneal tissue with an application to predict astigmatic keratotomy surgery. J Mech Behav Biomed Mater 74(2017):304–314CrossRefGoogle Scholar
  8. Auffarth GU, Wang L, Völcker HE (2000) Keratoconus evaluation using the orbscan topography system. J Cataract Refract Surg 26(2):222–228.  https://doi.org/10.1016/S0886-3350(99)00355-7 CrossRefGoogle Scholar
  9. Barbara R, Barbara A, Naftali M (2015) Depth evaluation of inteded vs intacts intrastromal ring segments using opitcal coherence tomography. Eye 30:102–110CrossRefGoogle Scholar
  10. Benoit A, Latour G, Schanne-Klein MC, Allain JM (2015) Simultaneous microstructrual and mechanical characterzation of human corneas at increasing pressure. J Mech Behav Biomed Mater 60(2016):93–105Google Scholar
  11. Colin J, Cochenre B, Savary G, Malet F, Holmes-Higgin D (2001) INTACS inserts for treating keratoconus. Am Acad Ophtalmol 108(8):1409–1414CrossRefGoogle Scholar
  12. Colin J, Kiliç A (2012) Surgical techniques for ICRS Implantation. Cataract Refract Surg Today. https://crstodayeurope.com/articles/2012-jul/surgical-techniques-for-icrs-implantation/
  13. Coskunseven E, Kymionis GD, Tsiklis NS, Atun S, Arslan E, Jankov MR, Pallikaris IG (2008) One-year results of intrastromal corneal ring segment implantation (keraring) using femtosecond laser in patients with keratoconus. Am J Ophthalmol 145(5):775–779.e1.  https://doi.org/10.1016/j.ajo.2007.12.022
  14. Coudrillier B, Pijanka J, Jefferys J, Sorensen T, Quigley HA, Boote C, Nguyen TD (2015) Effects of age and diabetes on scleral stiffness. J Biomech Eng 137(7):1–10.  https://doi.org/10.1115/1.4029986 CrossRefGoogle Scholar
  15. Dan ZR, Timothy JA, Marine G, Raksha U, Ronald HS (2017) Role of corneal biomechanics in the diagnosis and management of keratoconus. In: Alió JL (ed) Keratoconus: recent advances in diagnosis and treatments, 1st edn. Springer Nature, Cham, pp 141–150Google Scholar
  16. Elsheikh E, Alhasso D, Rama P (2008) Assessment of the epithelium’s contribution to corneal biomechanics. Exp Eye Res 86:445–451.  https://doi.org/10.1016/j.exer.2007.12.002 CrossRefGoogle Scholar
  17. Fangjun B, Brendan G, QinMei W, Ahmed E (2016) Consideration of corneal biomechanics in the diagnosis and management of keratoconus: is it important? Eye Vis 2016:3–18.  https://doi.org/10.1186/s40662-016-0048-4 Google Scholar
  18. Fernandez-Vega L, Lisa C, Poo-López A, Madrid-Costa D, Merayo-Lloves J, Alfonso JF (2016) Intrastromal corneal ring segment implantation in 409 paracentral keratoconic eyes. Cornea 35(11):1421–1426CrossRefGoogle Scholar
  19. Garcia-Porta N, Fernandes P, Queiros A, Salgado-Borges J, Parafita-Mato M, González-Méijome JM (2014) Corneal biomechanical properties in different ocular conditions and new measurement techniques. ISRN Ophthalmol 2014:1–20CrossRefGoogle Scholar
  20. Garzón N, Galán FP (2013) Orbscan: topographical maps. Gac Opt 420:24–28Google Scholar
  21. Gomes JA, Tan D, Rapuano CJ, Belin MW, Renato AJ, Guell JL, Malecaze F, Nishida K, Sangwan VS (2015) Global consensus on keratoconus and ectasic disease. Cornea 34(4):359–369CrossRefGoogle Scholar
  22. Guang-Ming Dai G (2008) Wavefront optics for vision correction. SPI Press, BellinghamGoogle Scholar
  23. Guarnieri FA, Ferrara P, Torquetti L (2015) Biomechanics of additive surgery: intracorneal rings.  https://doi.org/10.1007/978-1-4939-1767-9
  24. Hernández-Gómez G, Malacara-Doblado D, Malacara-Hernández Z, Malacara-Hernández D (2014) Modal processing of hartmann and shack-hartmann patterns by means of a least squares fitting of the transverse aberrations. Appl Opt 53(1):7422–7434.  https://doi.org/10.1364/AO.53.007422 CrossRefGoogle Scholar
  25. Hong J, Xu J, Wei A, Deng SX, Cui X, Yu X, Sun X (2013) A new tonometer? The corvis st tonometer: clinical comparison with noncontact and goldmann applanation tonometers. Invest Ophthalmol Vis Sci 54:659–665CrossRefGoogle Scholar
  26. Jadidi K, Mosavi SA, Nejat F, Naderi M, Janani L, Serahati S (2014) Intrastromal corneal ring segement implantation (keraring 355\(^{\circ }\)) in patients with central keratoconus: 6-month follow-up. J Ophthalmol 2015:1–8.  https://doi.org/10.1155/2015/916385 CrossRefGoogle Scholar
  27. Kahn SN, Shiakolas PS (2016) To study the effects of intrastromal corneal ring geometry and surgical condictions on the postsurgical outcomes through finite element analysis. J Mech Med Biol 16(7):1–16.  https://doi.org/10.1142/S0219519416501013 Google Scholar
  28. Kling S, Marcos S (2013) Finite-element modeling of intrastromal ring segment implantation into a hyperelastic cornea. Investig Ophthalmol Vis Sci 54(1):881–889CrossRefGoogle Scholar
  29. Lago M, Rupérez MJ, Monserrat C, Martínez-Martínez F, Martínez-Sanchís S, Larra E, Díez-Ajenjo M, Peris-Martínez C (2015) Patient-specific simulation of the intrastromal ring segment implantation in corneas with keratoconus. J Mech Behav Biomed Mater 51:260–268.  https://doi.org/10.1016/j.jmbbm.2015.07.023 CrossRefGoogle Scholar
  30. Lakshminarayanan V, Fleck A (2011) Zernike polynomials: a guide. J Mod Opt 58(7):545–561.  https://doi.org/10.1080/09500340.2011.554896 CrossRefGoogle Scholar
  31. Liu XL, Li PH, Fournie P, Malecaze F (2015) Investigation of the efficency of intrastromal ring segments with cross-linking using different sequence and timing for keratoconus. Int J Ophthalmol 8(4):703–708.  https://doi.org/10.3980/j.issn.2222-3959.2015.04.11 Google Scholar
  32. Malacara D, Malacara Z (2003) Handbook of optical design, 2nd edn. Marcel Dekker, New YorkCrossRefGoogle Scholar
  33. Montgomery DC (2001) Desgin and analysis of experiments, 5th edn. Wiley, New YorkGoogle Scholar
  34. Navarro R, González L, Hernández JL (2006) Optics of the average normal cornea from general and canonical representations of its surface topography. J Opt Soc Am 23(2):219–32.  https://doi.org/10.1364/JOSAA.23.000219 CrossRefGoogle Scholar
  35. O’Brat D (2017) Corneal collagen cross-linking for corneal ectasias. In: Alió JL (ed) Keratoconus: recent advances in diagnosis and treatments, 1st edn. Springer Nature, Cham, pp 219–238Google Scholar
  36. Pandolfi A, Vasta M (2012) Fiber distributed hyperelastic modeling of biological tissues. Mech Mater 44(Supplement C):151–162.  https://doi.org/10.1016/j.mechmat.2011.06.004
  37. Peris-Martínez C, Cisneros Lanuza ÁL (2014) Microscopía de la Sornea Sana correlación con la cornea ectásica. In: del Buey MÁ, Peris-Martínez, C (eds) Biomechanics and architecture corneal, 1st edn. Elsevier, Barcelona, pp 25–34Google Scholar
  38. Piñero DP, Alió JL, Kady BE, Coskunseven E, Morbelli H, Uceda-Montanes A, Maldonado MJ, Cuevas D, Pascual I (2009) Refractive and aberrometric outcomes of intracorneal segments for keratoconus: mechanical versus femtosecond-assited procedures. Am Acad Ophtalmol 116:1675–1687CrossRefGoogle Scholar
  39. Rabinowitz YS (1998) Keratoconus. Surv Ophthalmol 42(4):297–319.  https://doi.org/10.1016/S0039-6257(97)00119-7 CrossRefGoogle Scholar
  40. Ramez B, Andrew MJT, Parwez H, David FA, Adel B (2017) Epidemiology of keratoconus. In: Alió JL (ed) Keratoconus: recent advances in diagnosis and treatments, 1st edn. Springer Nature, Cham, pp 13–23Google Scholar
  41. Scarcelli G, Yun SH (2017) Keratoconus: recent advances in diagnosis and treatments. Chap 14:167–173Google Scholar
  42. Shabayek MH, Alió JL (2007) Intrastromal corneal ring segment implantation by femtosecond laser for keratoconus correction. Am Acad Ophtalmol 114:1643–1652CrossRefGoogle Scholar
  43. Sherwin T, Ismail S, Loh IP, McGhee JJ (2017) Histopathology (from keratoconus pathology to pathogenesis). In: Alió JL (ed) Keratoconus: recent advances in diagnosis and treatments, 1st edn. Springer Nature, Cham, pp 25–41Google Scholar
  44. Suiter BG, Twa MD, Ruckhofer J, Schanzlin DJ (2000) A comparison of visual acuity, predictability and visual function outcomes after intracorneal ring segments and laser in situ keratomileusis. Trans Am Ophthalmol Soci 98:51–57Google Scholar
  45. Thibos LN, Hong X, Bradley A, Applegate RA (2004) Accuracy and precision of objective refraction from wavefront aberrations. J Vis 4(4):329–351.  https://doi.org/10.1167/4.4.9 CrossRefGoogle Scholar
  46. Torquetti L, Arce C, Merayo-Lloves J, Ferrara G, Ferrara P, Signorelli B, Signorelli A (2016) Evaluation of anterior and posterior surfaces of cornea using a dual scheimpflug analyzer in keratoconus patients implanted with intrastromal corenal ring segements. Int J Ophthalmol 9(9):1283–1288.  https://doi.org/10.18240/ijo.2016.09.08 Google Scholar
  47. Torquetti L, Ferrara G, Almeida F, Cunha L, Ferrara P, Merayo-Lloves J (2013) Clinical outcomes after intrastromal corneal ring segments reoperation in keratoconus patients. Int J Ophthalmol 6(6):796–800.  https://doi.org/10.3980/j.issn.2222-3959.2013.06.10 Google Scholar
  48. Vega-Estrada A, Alió JL (2016) The use of intracorneal ring segments in keratoconus. Eye Vis 2016:3–8Google Scholar
  49. Al-Tuwairqui WS, Osuagwu UL, Razzouk H, AlHarbi A, Ogbuehi KC (2016) Clinical evaluation of two types of intracorneal ring segments (ICRS) for keratoconus. Int Ophthalmol 37(5):1185–1198.  https://doi.org/10.1007/s10792-016-0385-2 CrossRefGoogle Scholar
  50. Zare MA, Hashemi H, Salari MR (2007) Intracorneal ring segment implantation for the management of keratoconus: safety and efficacy. J Cataract Refract Surg 33(11):1886–1891.  https://doi.org/10.1016/j.jcrs.2007.06.055 CrossRefGoogle Scholar

Copyright information

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

Authors and Affiliations

  • Julio Flecha-Lescún
    • 1
  • Begoña Calvo
    • 1
    • 2
  • Jesús Zurita
    • 3
  • Miguel Ángel Ariza-Gracia
    • 1
    • 4
  1. 1.Applied Mechanics and Bioengineering (AMB); Aragón Institute for Engineering Research(i3A)University of ZaragozaZaragozaSpain
  2. 2.Bioengineering, Biomaterials and Nanomedicine OnlineBiomedical Research Center (CIBBER-BBN)MadridSpain
  3. 3.Department of Mechanical EngineeringPublic University of NavarraPamplonaSpain
  4. 4.Computational Biomechanics (CB), Institute for Surgical Technology and Biomechanics(ISTB)University of BernBernSwitzerland

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