Prospective, randomized contralateral eye study of accelerated and conventional corneal cross-linking in pediatric keratoconus

Original Paper
  • 23 Downloads

Abstract

Purpose

To compare the outcomes of two different cross-linking (CXL) protocols, in pediatric keratoconus eyes.

Materials and methods

In this prospective randomized contralateral eye interventional study, 68 eyes of 34 patients, 9–16 years old, underwent CXL and enrolled between October 2011 and October 2013. Group A represents conventional riboflavin–ultraviolet A (UVA)-induced CXL with 30 min of exposure to UVA irradiation of 3 mW/cm2. Group B represents accelerated cross-linking with 5 min of continuous UVA irradiation of 18 mW/cm2. In either group, total energy delivered was adjusted to 5.4 J/cm2. Follow-up of all patients was accomplished throughout the postoperative 3 years, and the data from the preoperative, 12, 24, and 36 months visits were analyzed and compared in both groups. Uncorrected visual acuity, corrected distance visual acuity, steepest keratometry (Kmax), corneal astigmatism (simulated K), total wavefront aberrations, central corneal thickness (CCT), corneal densitometry, manifest refraction spherical equivalent, and endothelial cell density (ECD) were evaluated at baseline, 12, 24, and 36 months post-CXL.

Results

At 1-year assessment, the mean value of UCVA, CDVA, and Kmax showed a statistically significant difference between both groups, without any documented change in the variables throughout the remaining follow-up (1–3-year) period. Twelve months postoperatively, mean LogMAR UCVA and CDVA were (0.11 ± 1.60) and (0.03 ± 1.60), respectively, in accelerated CXL group, compared to conventional CXL group values of (0.20 ± 1.00) and (0.06 ± 1.22), showing a statistically significant difference (P < 0.05). Mean Kmax in accelerated CXL group (45.47 ± 0.44) showed a statistically significant difference (P < 0.05) compared to conventional CXL group (46.41 ± 1.59) at 12 months post-CXL. On the other hand, wavefront aberrations, simulated K, corneal densitometry, ECD, and CCT changes showed nonstatistically significant difference in conventional CXL group, compared to accelerated CXL group (P > 0.05) throughout the follow-up course.

Conclusions

Both conventional and accelerated CXL improved UCVA and CDVA, attenuated disease progression, and reduced corneal steepness and wavefront aberrations at 1, 2, and 3 years postoperatively. In no case did keratoconus progress over the 36-month follow-up.

Keywords

Accelerated Conventional Cross-linking Pediatric Keratoconus 

Notes

Acknowledgements

The authors thank Dr Ahmed Ibrahim for referring cases of pediatric keratoconus and his independent follow-up of cases.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

The study adhered to the tenets of Declaration of Helsinki, and IRB approval was obtained from an ethical committee—Magrabi Aseer Hospital.

Informed consent

An informed consent was obtained from all parents.

References

  1. 1.
    Brooks NO, Greenstein SA, Fry K, Hersh PS (2012) Patient subjective visual function after corneal collagen crosslinking for keratoconus and corneal ectasia. J Cataract Refract Surg 38:615–6198CrossRefPubMedGoogle Scholar
  2. 2.
    Greenstein SA, Fry KL, Hersh PS (2011) Corneal topography indices after corneal collagen crosslinking for keratoconus and corneal ectasia: one-year results. J Cataract Refract Surg 37:1282–1290CrossRefPubMedGoogle Scholar
  3. 3.
    Wollensak G (2006) Crosslinking treatment of progressive keratoconus: new hope. Curr Opin Ophthalmol 17:356–360CrossRefPubMedGoogle Scholar
  4. 4.
    Spoerl E, Wollensak G, Seiler T (2004) Increased resistance of crosslinked cornea against enzymatic digestion. Curr Eye Res 29:35–40CrossRefPubMedGoogle Scholar
  5. 5.
    Wollensak G, Spoerl E, Seiler T (2003) Stress-strain measurements of human and porcine corneas after riboflavin-ultraviolet-A induced cross-linking. J Cataract Refract Surg 29:1780–1785CrossRefPubMedGoogle Scholar
  6. 6.
    Chatzis N, Hafezi F (2012) Progression of keratoconus and efficacy of pediatric corneal collagen cross-linking in children and adolescents. J Refract Surg 28:753–758CrossRefPubMedGoogle Scholar
  7. 7.
    Vanathi M, Panda A, Vengayil S, Chaudhuri Z, Dada T (2009) Pediatric keratoplasty. Surv Ophthalmol 54:245–271CrossRefPubMedGoogle Scholar
  8. 8.
    Wollensak G, Spoerl E, Seiler T (2003) Stress-strain measurements of human and porcine corneas after riboflavin-ultraviolet-A-induced cross-linking. J Cataract Refract Surg 29:1780–1785CrossRefPubMedGoogle Scholar
  9. 9.
    Hersh PS, Greenstein SA, Fry KL (2011) Corneal collagen crosslinking for keratoconus and corneal ectasia: one-year results. J Cataract Refract Surg 37:149–160CrossRefPubMedGoogle Scholar
  10. 10.
    Krachmer JH, Feder RS, Belin MW (1984) Keratoconus and related non-inflammatory corneal thinning disorders. Surv Ophthalmol 28:293–322CrossRefPubMedGoogle Scholar
  11. 11.
    Vinciguerra P, Albe E, Trazza S, Rosetta P, Vinciguerra R, Seiler T, Epstein D (2009) Refractive, topographic, tomographic, and aberrometric analysis of keratoconic eyes undergoing corneal cross-linking. Ophthalmology 116:369–378CrossRefPubMedGoogle Scholar
  12. 12.
    Greenstein SA, Hersh PS (2013) Characteristics influencing outcomes of corneal collagen crosslinking for keratoconus and ectasia: implications for patient selection. J Cataract Refract Surg 39:1133–1140CrossRefPubMedGoogle Scholar
  13. 13.
    Toprak I, Yayali V, Yildrim C (2014) Factors affecting outcomes of corneal collagen crosslinking treatment. Eye 28:41–46CrossRefPubMedGoogle Scholar
  14. 14.
    Witting-Silva C, Chan E, Islam FM, Wu T, Whiting M, Snibson GR (2014) A randomized, controlled trial of corneal collagen cross-linking in progressive keratoconus: three-year results. Ophthalmology 121(4):812–821CrossRefGoogle Scholar
  15. 15.
    Greenstein SA, Fry KL, Hersh MJ, Hersh PS (2012) Higher-order aberrations after corneal collagen crosslinking for keratoconus and corneal ectasia. J Cataract Refract Surg 38:292–302CrossRefPubMedGoogle Scholar
  16. 16.
    Bunsen RW, Roscoe HE (1862) Photochemical researches—Part V. On the measurement of the chemical action of direct and diffuse sunlight. Proc R Soc Lond 12:306–312CrossRefGoogle Scholar
  17. 17.
    Amsler M (1961) The, “forme fruste” of keratoconus. Wien Klin Wochenschr 73:842–843PubMedGoogle Scholar
  18. 18.
    Sridhar MS, Mahesh S, Bansal AK et al (2004) Pellucid marginal corneal degeneration. Ophthalmology 111:1102–1107CrossRefPubMedGoogle Scholar
  19. 19.
    Li X, Yang H, Rabinowitz YS (2009) Keratoconus: classification scheme based on videokeratography and clinical signs. J Cataract Refract Surg 35:1597–1603CrossRefPubMedPubMedCentralGoogle Scholar
  20. 20.
    Wittig-Silva C, Whiting M, Lamoureux E et al (2008) A randomized controlled trial of corneal collagen cross-linking in progressive keratoconus: preliminary results. J Refract Surg 24:S720–S725PubMedGoogle Scholar
  21. 21.
    Minoru T, Mariko M, Tukezban H (2014) Accelerated versus conventional corneal collagen crosslinking. J Cataract Refract Surg 40:1013–1020CrossRefGoogle Scholar
  22. 22.
    Dalal A, David T, Pierre F, Florence M, Caroline G, Anne G, Francois M, Joseph C (2011) Corneal collagen crosslinking in progressive keratoconus: multicenter results from the French National Reference Center for Keratoconus. J Cataract Refract Surg 37:2137–2143CrossRefGoogle Scholar
  23. 23.
    Abdelrahman G (2013) Transepithelial corneal collagen crosslinking for progressive keratoconus in a pediatric age group. J Cataract Refract Surg 39:1164–1170CrossRefGoogle Scholar
  24. 24.
    Ng AL, Chan TC, Cheng AC (2016) Conventional versus accelerated corneal collagen cross-linking in the treatment of keratoconus. Clin Exp Ophthalmol 44(1):8–14CrossRefPubMedGoogle Scholar
  25. 25.
    Greenstein SA, Fry KL, Hersh MJ, Hersh PS (2010) Natural history of corneal haze after collagen crosslinking for keratoconus and corneal ectasia: scheimpflug and biomicroscopic analysis. J Cataract Refract Surg 36:2105–2114CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Ophthalmology, Faculty of MedicineCairo UniversityCairoEgypt
  2. 2.Magrabi Eye HospitalAbhaKingdom of Saudi Arabia

Personalised recommendations