MMP9 and keratoconus: In this prospective pilot study involving pediatric eye-rubbers patients with progressive KC suffering from allergy, dry eye symptoms, and elevated tear MMP-9 levels, epi-off ACXL was associated with stabilization of corneal ectasia (Kmax), improvement in visual function (CDVA) and tear film stability (cBUT), reduction in subjective symptom burden (OSDI), and a marked decline in tear MMP-9 concentration, demonstrating a favorable safety and tolerability profile.