The Ocular Axial Length Growth Of Induced By Collagen Cross-linking Using Riboflavin And Ultravolet A On Equtorial Sclera

Part IThe effect of riboflavin-ultraviolet A collagen cross-linking on biomechanical properties of scleraObjective To study the effect of collagen riboflavin-ultraviolet A cross-linking in biomechanical properties of sclera.Methods Out of40guinea pigs used in the study, in both groups the right eyes were intervened,20underwent collagen cross-linking using3.0mw/cm2ultraviolet A (UVA) and the application of0.1%riboflavin for30minutes. The remaining guinea pigs underwent an application of for30minutes. The right eyes were chosen in both groups. The changes in biomechanical properties of the sclera were investigated one month after surgery. In addition, they were examined histologically by light microscopy to evaluate any side effects. In addition, the sclera was examined by electron microscopy.Results The biomechanics of the sclera increased in the experimental group. Following the cross-linking treatment, the ultimate stress was increase of147%, Young’s modulus increase of193%and ultimate strain decrease of21.9%versus the control group. There were no pathological changes by light microscopy and fibroblast hyperplasia was increasingly found in the cross-linking area of the sclera by transmission-electron microscopy.Conclusions The collagen cross-linking on the sclera using riboflavin and ultraviolet A can effectively improve its biomechanical characteristics. There were no pathological changes by light microscopy and fibroblast hyperplasia was increasingly found in the cross-linking area of the sclera by transmission-electron microscopy. Part IIThe ocular axial length growth induced by collagen cross-linking using riboflavin and ultravolet A on equtorial scleraObjective To study the effect on axial length and diopter in guinea pigs after using collagen cross-linking riboflavin and ultraviolet Aon equtorial sclera.Methods Out of40guinea pigs used in the study,20underwent collagen cross-linking using3.0mw/cm2ultraviolet A (UVA) and the application of0.1%riboflavin for30minutes,The remaining guinea pigs underwent an application of0.1%riboflavin for30minutes. In both groups the right eyes were intervened. The changes of axial length and ocular refraction were investigated before surgery, two weeks and one month after surgery.Results Before the start of the experiment, there were no statistically significant differences in diopter and axial length between the groups and the eyes. In postoperative two weeks and one month, there were statistically significant differences in diopter and axial length between the right eyes and the opposite eyes in both groups. In postoperative two weeks and one month, the right eyes in the cross-linking group got relative6.19±1.14D,9.67±0.87D myopia, axial length extend0.59±0.14mm,0.89±0.07mm; the right eyes of form-deprivation group got relative3.93±0.52D,4.11±0.47D myopia, axial length extend0.36±0.09mm,0.51±0.09mm. After two weeks and one month, relative myopic diopter was deeper in the cross-linking group and the relative axial length extended more than form-deprivation group, the differences between the two groups was statistically significant; The myopia degree still progressed in postoperative one month compared to postoperative two weeks in cross-linking group, the differences between the two postoperative groups was statistically significant; The growth rate of myopia in form-deprivation group slowed down from postoperative two weeks, there was no statistically significant difference between the two postoperative groups.Conclusions The use of collagen cross-linking riboflavin and ultraviolet A on the equatorial area of the sclera which increases the ocular axial length and the degree of myopia may be extended as a new treatment for hypermetropia.