Accelerated CXL for stage 2 to 3 progressive keratoconus: 24-month outcomes
L.F. Troichenko, G.I. Drozhzhyna
SI “The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine”; Одеса (Україна)
TO CITE THIS ARTICLE: Troichenko L.F., Drozhzhyna G.I. Accelerated CXL for stage 2 to 3 progressive keratoconus: 24-month outcomes. J.ophthalmol.(Ukraine).2020;3:16-22. http://doi.org/10.31288/oftalmolzh202031622
Background: Ultraviolet (UV-X) corneal collagen cross-linking (CXL) involves photopolymerization of corneal collagen and in recent decades has been commonly employed for the treatment of stage 2 to 3 keratoconus. The high-intensity illumination of the UV-X™ 2000 Crosslinking System (Avedro, Inc., Waltham, Massachusetts) provides accelerated CXL (A-CXL), reducing treatment time threefold (to 10 minutes) compared with conventional CXL protocol.
Purpose: To assess 24-month outcomes of A-CXL for stage 2 to 3 progressive keratoconus.
Material and Methods: One hundred and nineteen patients (167 eyes) who underwent ACXL for keratoconus were included in this study. At 24 months, ocular changes were assessed in 40 eyes. A-CXL was carried out using the UV-X™ 2000 Crosslinking System at an irradiation intensity of 9 mW/cm?.
Results: Mean astigmatism decreased by 1.15 D to 3.02 ± 1.73 (SD) D (for n=40 eyes) and mean corneal refractive power as assessed by Kmax decreased by 3.4 D to 54.4 ± 6.62 (SD) D (median value, 54.3 D; n=40 eyes) at 24 months compared to baseline values. Mean thinnest local corneal thickness increased by 3.0 ?m (mean value, 462.7± 34.3 (SD) ?m; median value, 455.5 ?m; n=40 eyes; р = 0.009), mean uncorrected visual acuity increased by 0.2, and mean best-corrected visual acuity increased by 0.25 at 24 months compared to baseline values. Of the 40 eyes examined at 24 months, BCVA improved in 34 eyes (85%).
Conclusion: A-CXL for stage 2 to 3 progressive keratoconus resulted in a steady state of the pathological process, decrease in astigmatism by 1.15 D, decrease in corneal refractive power as assessed by Kmax by 3.4 D, and an increase in thinnest local corneal thickness by 3.0 ?m for the total study cohort, and improvement in BCVA in 85% of eyes at 24 months.
Keywords: keratoconus, cornea, cross-linking
1.Bikbov MM, Surkova VK. [Corneal collagen crosslinking for keratoconus]. A review. Ophthalmology in Russia. 2014;11(3):13-8. https://doi.org/10.18008/1816-5095-2014-3-13-19. Russian.
2.Birich TA, Chekina AIu, Aksionova NI. [Outcomes of treatment for keratoconus]. Oftalmologiia Belorusi. 2010;1(4):90-7. Russian.
3.Ivanovskaia EV, Vit VV, Golovchenko VG. [Immunological status of patients with various stages of keratoconus and keratoglobus]. Oftalmol Zh. 2000;5:40-4. Russian.
4.Drozhzhyna GI, Troychenko LF, Naumenko VA, et al. [Outcomes of accelerated corneal collagen cross-linking in keratoconus]. Oftalmol Zh. 2018;3:10-7. Russian.
5.Sevastiianov EN, Gorskova EN, Ekgard VF. [Keratoconus (etiology, pathogenesis, medicinal treatment): textbook]. Cheliabinsk: UGMADO;2005. Russian.
6.Solodkova EG, Remesnikov IA. [Modern approaches in the treatment progressive keratectasia]. Prakticheskaia meditsina. 2012;4:75-9. Russian.
7.Croghale NS. Epidemiology of keratoconus. Indian J Ophthalmol. 2013;61(8): 382-3.
8.Rabinowitz YS. Keratoconus. Surv Ophthalmol. 1998 Jan-Feb;42(4):297-319.
9.Georgiou T, Funnell CL, Cassels-Brown A, O’Conor R. Influence of ethnic origin on the incidence of keratoconus and associated atopic disease in Asians and white patients. Eye (Lond). 2004 Apr;18(4):379-83.
10.Li X, Rabinowitz YS, Rasheed K, Yang H. Longitudinal study of the normal eyes in unilateral keratoconus. Ophthalmology. 2004;111:440–6.
11.Gordon-Shaag A, Millodot M, Shneor E, Liu Y. Gordon-Shaag A, et al. The genetic and environmental factors for keratoconus. Biomed Res Int. 2015;2015:795738.
12.Zadnik K, Barr JT, Edrington TB, et al. Baseline findings in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. Invest Ophthalmol Vis Sci. 1998;39:2537–46.
13.Adel Alhayek, Pei-Rong Lu. Corneal collagen crosslinking in keratoconus and other eye disease. Int J Ophthalmol. 2015; 8(2): 407–18. doi: 10.3980/j.issn.2222-3959.2015.02.35.
14.Kohlhaas M, Spoerl E, Schilde T, et al. Biomechanical evidence of the distribution of cross-links in corneas treated with riboflavin and ultraviolet A light. J Cataract Refract Surg. 2006 Feb;32(2):279-83.
15.Nowak DM, Gajecka M. The genetics of keratoconus. Middle East Afr J Ophthalmol. 2011 Jan;18(1):2-6.
16.Spoerl E, Mrochen M, Sliney D, et al. Safety of UVA – riboflavin cross – linking of the cornea. Cornea. 2007 May;26(4):385-9.
17.Wollensak G, Spoerl E, Seiler T. Stress-strain measurements of human and porcine corneas after riboflavin/ultraviolet–A-induced cross-linking. J Cataract Refract Surg. 2003 Sep;29(9):1780-5.
18.Kymionis GD, Portaliou DM, Bouzoukis DI, et al. Herpetic keratitis with iritis after corneal crosslinking with riboflavin and ultraviolet A for keratoconus. J Cataract and Refract Surg. 2007 Nov;33(11):1982-4.
19.Macsai MS, Varley GA, Krachmer JH. Development of keratoconus after contact lens wear. Patient characteristics. Arch Ophthalmol. 1990 Apr;108(4):534-8.
20.Mazzotta C, Balestrazzi A, Traversi C, et al. Treatment of progressive keratoconus by riboflavin-UVA-induced cross-linking of corneal collagen; ultrastructural analysis by Heidelberg Retinal Tomograph II in vivo confocal microscopy in humans. Cornea. 2007 May;26(4):390-7.
21.Meek KM, Tuft SJ, Huang Y, et al. Changes in collagen orientation and distribution in keratoconus. Invest Ophthalmol Vis Sci. 2005. 2005 Jun;46(6):1948-56.
22.McQuaid R, Cummings AB, Mrochen M. The theory and art of corneal cross-linking. Indian J Ophthalmol. 2013 Aug;61(8):416-9.
23.Spoerl E, Huhle M, Seiler T. Induction of cross-links in corneal tissue. Exp Eye Res. 1998 Jan;66(1):97-103.
24.Spoerl E, Seiler T J. Techniques for stiffening the cornea. Refract Surg. 999 Nov-Dec;15(6):711-3.
25.Sp?rl E, Huhle M, Kasper M, Seiler T. [Increased rigidity of the cornea caused by intrastromal crosslinking]. Ophthalmologe. 1997 Dec;94(12):902-6. German.
26.Tsubota K, Mashima Y, Murata H, et al. Corneal epithelium in keratoconus. Cornea. 1995 Jan;14(1):77-83.
27.Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. – 2003 May;135(5):620-7.
28.Shajari M, Kolb CM, Agha B, Steinwender G, M?ller M, Herrmann E, et al. Comparison of standard and accelerated corneal cross-linking for the treatment of keratoconus: a meta-analysis. Acta Ophthalmol. 2019 Feb;97(1):e22-e35.
29.Sadoughi MM, Einollahi B, Baradaran-Rafii A, et al. Accelerated versus conventional corneal collagen cross-linking in patients with keratoconus: an intrapatient comparative study. Int Ophthalmol. 2018; 38: 67–74.
The authors certify that they have no conflicts of interest in the subject matter or materials discussed in this manuscript.