Clinical research on corneal biomechanical changes after keratoconus collagen cross-linking

Objective To observe corneal biomechanical changes in patients with keratoconus after corneal collagen cross-linking. Methods Prospective self-control study. Twenty-three eyes of 17 patients with primary keratoconus from Jan. 2018 to Jun. 2018 in Zhengzhou Second Hospital were analyzed. The age of patients ranged from 13 to 28 years, with average of (16.4±2.8) years. All cases were treated with riboflavin/ultraviolet A (UVA)-induced rapid epithelium-off corneal collagen cross-linking. All cases were observed with Corvis ST visualized corneal biomechanical measurement instrument and followed up for 12 months. Results The best corrected visual acuity (LogMAR) after operation increased from 0.42±0.19 to 0.29±0.15 (t=-8.043, P=0.000). The equivalent spherical diopter and the maximum curvature of the anterior corneal surface were decreased (t=-4.183, -5.188, P=0.000, 0.000). The thinnest corneal thickness postoperative was decreased compared with that before operation(t=-3.984, P=0.001). The first flattening time postoperative increased (t=7.793, P=0.000). The second flattening time and the maximum indentation depth decreased (t=-9.075, P=0.000, t=-3.280, P=0.003). Conclusion The visual acuity, corneal morphology and biomechanical parameters after the rapid epithelium-off corneal collagen cross-linking in patients with primary keratoconus are ameliorated significantly. Key words: Keratoconus; Cross-linking, collagen, corneal; Biomechanics, cornea