A Comparative Study Of Riboflavin-induced Transepithelial Collagen Cross-linking

Objective:To compare the clinical efficacy of CXL(corneal collagen crosslinking)induced by riboflavin in the treatment of progressive keratoconus.Methods:Retrospective control study.A total of 46 patients(74 eyes)diagnosed with progressive keratoconus and receiving CXL treatment in Hankou Aier Hospital from August 2016 to June 2018 were collected and divided into 3 groups:16 eyes were assigned to the osmotic agent CXL group(0.25%concentration of isosmotic riboflavin,carrier hydroxypropyl methyl cellulose);40 eyes were assigned to the iontophoresis CXL group(0.1%concentration of isosmotic riboflavin,carrier EDTA,tromethamine);18 eyes were assigned to epithelium-off CXL group(0.1%isosmotic riboflavin).All use accelerated scheme(370nm ultraviolet light,intensity 10m W/cm~2,total energy 5.4J/cm~2,continuous 9min).The BCVA(best corrected visual acuity),Kmax(maximum anterior surface curvature),corneal optical density,TCT(Thinnest corneal Thickness),ECD(Endothelial cell density)and SE(sphcrical equivalent)was checked before surgery and at 6,12 and 24months postoperatively.Results:The Kmax in the epithelium-off group at 24 months postoperatively was decreased by 1.63D(F=3.881,P=0.032),that in the iontophoresis CXL group at 24months postoperatively was decreased by 1.00D(F=3.212,P=0.041),and that in the osmotic agent group remained stable.At 24 months postoperatively,the TCT of the iontophoresis group increased by 2.3?m(F=4.164,P=0.02),and the TCT of the epithelium-off group decreased by 10.4?m(F=12.230,P<0.0001),the TCT of the osmotic agent group remained stable.BCVA,corneal optical density,ECD,and SE remained stable after all three types of CXL treatments.All patients in the three groups had no significant postoperative complications.Conclusion:All three types of CXL can effectively control the progression of progressive keratoconus.Epithelium-off CXL can reduce Kmax,but at the same time it can also reduce TCT.Epithelium-on CXL is safer and can also achieve the efficacy of controlling the development of keratoconus,among which iontophoresis type has better efficacy than osmotic agent type.