International Journal of Preventive Medicine (Int J Prev Med)2008-7802112016122417561756ENEye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, TehranEye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, TehranEye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, & Department of Ophthalmology, Kashan University of Medical Sciences, KashanIran Eye Bank, TehranEye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, TehranEye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, TehranIsfahan Eye Research Center, Feiz Hospital, Isfahan University of Medical Sciences, IsfahanIsfahan Eye Research Center, Feiz Hospital, Isfahan University of Medical Sciences, Isfahan20161224<p><strong>Background: </strong>To evaluate any change in tear indices and confocal microscopic findings after corneal collagen crosslinking (CXL) in patients with progressive keratoconus.</p><p><strong>Methods:</strong> Thirty‑two consecutive eyes from 23 patients having progressive keratoconus were enrolled in this prospective, interventional cohort study. The standard crosslinking surgery was performed for all patients. Visual, refractive, and topographic evaluations were done before and at 6 months after surgery. Tear function tests and confocal microscopic examination were<br />performed before and at 1 month and 6 months after the procedure.</p><p><strong>Results:</strong> There was no significant change in Schirmer‑1 test results and tear osmolarity at 1 month and 6 months after CXL. Using confocal microscopy, all eyes showed reduced<br />or absent subepithelial nerve plexus. Differences in basal epithelial cell density, epithelial mean cell area, and keratocyte density in anterior and middle stroma and endothelial cell<br />pleomorphism were all significant at 1 month and 6 months after CXL (P &lt; 0.05). No significant change was noted in endothelial cell count and their polymegathism at 6 months follow‑up.<br />Significant improvement was noted in uncorrected visual acuity, best corrected visual acuity, flattest corneal meridian (K2), and maximum keratometry in Pentacam (Kmax) after 6 months<br />of the procedure.</p><p><strong>Conclusions:</strong> While CXL would have no effect on tear indices and endothelial cell count, it can cause a significant reduction in subepithelial nerve plexus and significant alterations in epithelial<br />cell density in the anterior and middle stroma.</p><p><strong>Keywords: </strong>Confocal microscopy, corneal collagen crosslinking, keratoconus</p>http://ijpm.mui.ac.ir/index.php/ijpm/article/view/1756http://ijpm.mui.ac.ir/index.php/ijpm/article/download/1756/2046