Cross-linking uses ultra-violate rays to induce covalent bonds between collagen fibers and enhancement of corneal tissue. The purpose of this study was to use confocal microscopy to analyze microstructural changes, after corneal collagen cross-linking in keratoconus patients

Total of 45 keratoconic eyes was included in this study. All patients underwent complete ophthalmologic examinations. Keratocytes and the presence of activated keratocytes were calculated pre and post-operativelyusing confocal microscopy

One year after surgery, best corrected and uncorrected visual acuity increased significantly (p<0.001). Spherical equivalent and spherical refractive errors reduced significantly (p<0.001). The reduction in density of anterior and mid stromal keratocytes was significant (p<0.001). The percentage of activated keratocytes showed a significant increase one month after cross-linking (p<0.001) albeit this percent reduced as the corneal healing proceeded. The endothelia showed no significant reduction during the follow up

Collagen cross-linking induced significant reduction in keratocyte density. Activated keratocytes increased significantly after cross-linking which showed reduction with improvement of corneal healing. Hyper reflective structures were observed consistent with the stromal collagen structures post-operatively which could be a clue to increased corneal biomechanics. The consistency in corneal endothelium numbers proves the safety of this technique