Clinical observation of transepithelial corneal collagen cross-linking by lontophoresis of riboflavin in treatment of keratoconus.

Purpose: To evaluate the efficacy and safety of transepithelial collagen cross-linking by iontophoretic delivery of riboflavin in treatment of progressive keratoconus.

Methods: Eleven patients (15 eyes) with progressive keratoconus were enrolled. After 0.1% riboflavin-distilled water solution was deliveried via transepithelial iontophpresis for 5 min with 1 mA current, and ultraviolet radiation (370 nm, 3 mW/cm2) was performed at a 1.5 cm distance for 30 min. The follow up were 6 months in all eyes. The uncorrected visual acuity, corrected visual acuity, endothelial cell counting, corneal thickness, intraocular pressure, corneal curvature, corneal topography, OCT and corneal opacity before and 6-month after surgery were analyzed.

Results: At 6 month postoperatively, mean uncorrected visual acuity and corrected visual acuity changed from 0.36 to 0.30 and from 0.42 to 0.57 without statistical significance. The mean value of each index of corneal curvature declined without statistical significance.Kmax value dereased from 60.91 to 59.91, and the astigmatism declined from 3.86 to 3.19. Central corneal thickness decreased from 460.93 μm to 455.40 μm, and thinnest corneal thickness declined from 450.87 μm to 440.60 μm with no statistical significance. Intraocular pressure was significantly elevated from 10.85 mmHg to 12.62 mmHg. Endothelial cell count did not change significantly. No corneal haze occurred. Mean depth of corneal demarcation line was 288.46 μm at 1 month postoperatively.

Conclusion: Transepithelial corneal collagen cross-linking by iontophoresis is effective and safe in the treatment of progressive keratoconus, and yields stable clinical outcomes during 6-month follow up. However, long-term follow up is urgently required.