Persistent corneal edema after collagen cross-linking for keratoconus.

PURPOSE: To present a new complication of persistent corneal edema after collagen cross-linking (CXL) in keratoconus patients.

DESIGN: Retrospective case series of postoperative corneal edema after CXL.

METHODS: study population: All patients who underwent CXL treatment with subsequent corneal edema. Patients with stromal haze were excluded. intervention: The CXL treatments used the Dresden protocol with corneal thickness of more than 400 μm after epithelium was removed. main outcome measure: The resolution of corneal edema after surgery.

RESULTS: Postoperative corneal edema was identified in 10 (2.9%) of 350 patients who were followed up for a mean of 14 ± 4 months. The edema started on postoperative day 1 (10/10) and increased for 3 weeks. Additional findings included: deep vascularization (2 eyes; 20%), iris atrophy (6 eyes; 60%), pigment dispersion (5 eyes; 50%), persistent epithelial defect (3 eyes; 30%), and infectious keratitis (1 eye; 10%). Specular microscopy was unsuccessful, but the fellow untreated eyes had normal endothelial counts. Intraocular pressure and lenticular evaluations were normal. Corneal edema improved in 4 patients and resolved in 1 patient. In these 5 patients, the logarithm of the minimal angle of resolution best-corrected visual acuity was 0.5 ± 0.18. Penetrating keratoplasty was offered to 5 patients when improvement plateaued at 3 months, but only 2 patients underwent penetrating keratoplasty.

CONCLUSIONS: CXL is a safe and effective procedure with few known side effects. This case series reports the possibility of corneal endothelial damage with visually significant corneal edema after CXL treatment. Based on the extent of endothelial damage, patients may require penetrating keratoplasty.