International Ophthalmology

, Volume 39, Issue 9, pp 2041–2048 | Cite as

Correlation of central and peripheral keratometric parameters after corneal collagen cross-linking in keratoconus patients

  • C. CaginiEmail author
  • G. Di Lascio
  • M. Messina
  • F. Riccitelli
  • HS Dua
Original Paper



To evaluate the difference in the central and peripheral keratometric parameters in patients with keratoconus after corneal collagen cross-linking (CXL).


Forty-eight eyes of 32 patients (18 males, 16–28 years) affected by progressive keratoconus in different stages of evolution underwent CXL using the standard epithelium-off protocol. Corneal thickness and corneal curvature before CXL and after 6 and 12 months using the Sirius tomographer were analyzed. The values of the mean corneal thickness at the corneal apex (CAT), center of the pupil (PCT), thinnest point (CTTL) and along concentric circles of 2, 4, 6, 8, 8.5, 9, 9.5 and 10 mm diameter were evaluated; the values of the mean curvature at the corneal apex and at the points in which the inferior, superior, nasal and temporal meridians crossed the above-mentioned concentric circles were also evaluated.


The mean preoperative values for CAT, PCT and CTTL were 461.4 ± 30.3, 475.3 ± 30.5 and 441 ± 32.0, respectively. The values after 12 months of CXL were 444.6 ± 36.2, 451.6 ± 36.7 and 418.2 ± 41.4. The peripheral corneal thickness at the eight points ranged from 479 to 733 preoperatively. At 12-month post-CXL, the values ranged from 444.6 to 734.1. The mean posterior curvature from apex to periphery ranged from − 4.5 to − 9.1 days preoperatively and from − 4.5 to − 9.2 days at 12 months. These were not statistically significant (ANOVA and unpaired T test).


Our data suggest that CXL over an 8-mm zone can stabilize the peripheral cornea. Longer-term follow-up studies on the peripheral cornea after CXL will provide useful information.


Keratoconus Cross-linking Cornea periphery Curvature Thickness 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Human and animal rights statement

This article does not contain any studies with animals performed by any of the authors.

Ethical approval

All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Declaration of Helsinki and its later amendments.

Informed consent

The study is a retrospective analysis of instrumental examinations carried out previously: For this reason, authors did not ask informed consent.


  1. 1.
    Vazirani J, Basu S (2013) Keratoconus: current perspectives. Clin Ophthalmol 7:2019–2030Google Scholar
  2. 2.
    Parker JS, Van Dijk K, Melles GR (2015) Treatment options for advanced keratoconus: a review. Surv Ophthalmol 60:459–480CrossRefGoogle Scholar
  3. 3.
    Giacomin NT, Mello GR, Medeiros CS et al (2016) Intracorneal ring segments implantation for corneal ectasia. J Refract Surg 32:829–839CrossRefGoogle Scholar
  4. 4.
    Israel M, Yousif MO, Osman NA et al (2016) Keratoconus correction using a new model of intrastromal corneal ring segments. J Cataract Refract Surg 42:444–454CrossRefGoogle Scholar
  5. 5.
    Recalde JI, Acera A, Rodríguez-Agirretxe I et al (2017) Ocular surface disease parameters after collagen cross-linking for keratoconus. Cornea 36:148–152CrossRefGoogle Scholar
  6. 6.
    Hycl J, Janek M, Valesová L et al (2003) Experimental correction of irregular astigmatism in patients with keratoconus using diode laser thermal keratoplasty. Cesk Slov Oftalmol 59:382–391Google Scholar
  7. 7.
    Assaf A, Kotb A (2015) Simultaneous corneal crosslinking and surface ablation combined with phakic intraocular lens implantation for managing keratoconus. Int Ophthalmol 35:411–419CrossRefGoogle Scholar
  8. 8.
    Feizi S, Javadi MA, Rezaei Kanavi M (2012) Recurrent keratoconus in a corneal graft after deep anterior lamellar keratoplasty. J Ophthalmic Vis Res 7:328–331Google Scholar
  9. 9.
    Said DG, Faraj L, Elalfy MS et al (2014) Atypical hydrops in keratoconus. Int Ophthalmol 34:951–955CrossRefGoogle Scholar
  10. 10.
    Yahia Chérif H, Gueudry J, Afriat M et al (2015) Efficacy and safety of pre-Descemet’s membrane sutures for the management of acute corneal hydrops in keratoconus. Br J Ophthalmol 99:773–777CrossRefGoogle Scholar
  11. 11.
    Mastropasqua L (2015) Collagen cross-linking: when and how? A review of the state of the art of the technique and new perspectives. Eye Vis (Lond) 29(2):19CrossRefGoogle Scholar
  12. 12.
    Wollensak G (2006) Crosslinking treatment of progressive keratoconus: new hope. Curr Opin Ophthalmol 17:356–360CrossRefGoogle Scholar
  13. 13.
    Galvis V, Tello A, Ortiz A et al (2017) Patient selection for corneal collagen cross-linking: an updated review. Clin Ophthalmol 11:657–668CrossRefGoogle Scholar
  14. 14.
    Shafik Shaheen M, Lolah MM, Piñero DP (2018) The 7-year outcomes of epithelium-off corneal cross-linking in progressive keratoconus. J Refract Surg 1(34):181–186CrossRefGoogle Scholar
  15. 15.
    Noor IH, Seiler TG, Noor K et al (2018) Continued long-term flattening after corneal cross-linking for keratoconus. J Refract Surg 1(34):567–570CrossRefGoogle Scholar
  16. 16.
    O’Donnell C, Maldonado-Codina C (2005) Agreement and repeatability of central thickness measurement in normal corneas using ultrasound pachymetry and the OCULUS Pentacam. Cornea 24:920–924CrossRefGoogle Scholar
  17. 17.
    Lackner B, Schmidinger G, Pieh S et al (2005) Repeatability and reproducibility of central corneal thickness measurement with Pentacam, Orb- scan, and ultrasound. Optom Vis Sci 82:892–899CrossRefGoogle Scholar
  18. 18.
    Yam JC, Cheng AC (2013) Reduced cross-linking demarcation line depth at the peripheral cornea after corneal collagen cross-linking. J Refract Surg 29:49–53CrossRefGoogle Scholar
  19. 19.
    Koller T, Schumacher S, Fankhauser F 2nd et al (2013) Riboflavin/ultraviolet a crosslinking of the paracentral cornea. Cornea 32:165–168CrossRefGoogle Scholar
  20. 20.
    Ng AL, Chan TC, Lai JS et al (2015) Comparison of the central and peripheral corneal stromal demarcation line depth in conventional versus accelerated collagen cross-linking. Cornea 34:1432–1436CrossRefGoogle Scholar
  21. 21.
    Seiler T, Hafezi F (2006) Corneal cross-linking-induced stromal demarcation line. Cornea 25:1057–1059CrossRefGoogle Scholar
  22. 22.
    Spadea L, Tonti E, Vingolo EM (2016) Corneal stromal demarcation line after collagen cross-linking in corneal ectatic diseases: a review of the literature. Clin Ophthalmol 10:1803–1810CrossRefGoogle Scholar
  23. 23.
    Richoz O, Tabibian D, Hammer A et al (2014) The effect of standard and high-fluence corneal cross-linking (CXL) on cornea and limbus. Invest Ophthalmol Vis Sci 55:5783–5787CrossRefGoogle Scholar
  24. 24.
    Patel SV, Malta JB, Banitt MR et al (2009) Recurrent ectasia in corneal grafts and outcomes of repeat keratoplasty for keratoconus. Br J Ophthalmol 93:191–197CrossRefGoogle Scholar
  25. 25.
    McQuaid R, Mrochen M, Vohnsen B (2016) Rate of riboflavin diffusion from intrastromal channels before corneal crosslinking. J Cataract Refract Surg 42:462–468CrossRefGoogle Scholar
  26. 26.
    Hashemi H, Seyedian MA, Miraftab M (2013) Corneal collagen cross-linking with riboflavin and ultraviolet a irradiation for keratoconus: long-term results. Ophthalmology 120:1515–1520CrossRefGoogle Scholar
  27. 27.
    Mazzotta C, Traversi C, Baiocchi S et al (2018) Corneal collagen cross-linking with riboflavin and ultraviolet a light for pediatric keratoconus: ten-year results. Cornea 37:560–566CrossRefGoogle Scholar
  28. 28.
    Kremer I, Eagle RC, Rapuano CJ et al (1995) Histologic evidence of recurrent keratoconus seven years after keratoplasty. Am J Ophthalmol 119:511–512CrossRefGoogle Scholar
  29. 29.
    Prospero Ponce CM, Rocha KM, Smith SD et al (2009) Central and peripheral corneal thickness measured with optical coherence tomography, Scheimpflug imaging, and ultrasound pachymetry in normal, keratoconus-suspect, and post-laser in situ keratomileusis eyes. J Cataract Refract Surg 35:1055–1062CrossRefGoogle Scholar
  30. 30.
    Brautaset RL, Nilsson M, Miller WL et al (2013) Central and peripheral corneal thinning in keratoconus. Cornea 32:257–261CrossRefGoogle Scholar
  31. 31.
    Fares U, Otri AM, Al-Aqaba MA et al (2012) Correlation of central and peripheral corneal thickness in healthy corneas. Cont Lens Anterior Eye 35:39–45CrossRefGoogle Scholar
  32. 32.
    Liu XL, Li PH, Fournie P et al (2015) Investigation of the efficiency of intrastromal ring segments with cross-linking using different sequence and timing for keratoconus. Int J Ophthalmol 8:703–708Google Scholar
  33. 33.
    Mastropasqua L, Nubile M, Salgari N et al (2018) Femtosecond laser-assisted stromal lenticule addition keratoplasty for the treatment of advanced keratoconus: a preliminary study. J Refract Surg 34:36–44CrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.Ophthalmology Section, Department of Biomedical and Surgical Sciences, S. Maria della Misericordia HospitalUniversity of PerugiaPerugiaItaly
  2. 2.Section of Academic Ophthalmology, Division of Clinical Neuroscience, Nottingham University Hospitals NHS TrustUniversity of NottinghamNottinghamUK

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