Abstract
Purpose: :
To assess the efficacy and safety of Riboflavin and Ultraviolet A induced corneal cross-linking (CXL) in progressive keratoconus and in post laser in-situ keratomlieusis ectasia (PLE) after 6 to 12 months follow-up.
Methods: :
15 eyes of 14 patients with topographically or clinically (change of refraction) progressive keratoconus (13 eyes) and PLE (2 eyes) were included. Additional inclusion criteria were minimal and central corneal thickness (MCT,CCT) > 450 micron : Uncorrected and best corrected visual acuity (UCVA, BCVA), corneal anterior and posterior topography, CCT and MCT from optical corneal thickness maps (Pentacam HR, Zeiss), were pre- and postoperatively recorded. CXL was performed after explanation of the procedure and obtaining an informed consent. After local anesthesia with oxybuprocain epithelium was removed after 25 seconds incubation with alcohol (20%) in 8 mm diameter well. Riboflavin solution 0,1% was administered every 2 minutes for 30 minutes on the eye and activated by illumination with ultraviolet (UV-A) 365 nm light at 9 mm diameter using UV LED lamp (UV-X, Peschke) 3 mw/sqcm for 30 minutes. Therapeutic contact lens was used for 5-7 days until the epithelium was completly closed. Topical antibiotic (Ofloxacin, Bauch&Lomb) and steroid eye drops (Prednisolon 1% , Allergan) were used for 1-2 weeks. Corneal scans and refraction measurments were done every 3 months
Results: :
Efficacy: In 12 eyes BCVA did not change and in 3 eyes improved in the follow up period. The steepest keratometrie values increased in 3, were stable in 8 and decreased in 4 of 15 eyes. The average 3 mm central keratometry and keratometric astigmatismus increased in 3 eyes , unchanged in 8 eyes and decreased in 4 eyes. Corneal posterior topography values were stayed in all of the eyes. Safety: None of the treated eyes suffered of severe complications such as infectious keratitis, clinical endothelial decompansation, or clinical epithel stem cell deficency. 6 eyes developed stromal haze that improved with topical steroid therapy.
Conclusions: :
CXL seems to be a safe and effective theraupeutical option for progressive keratoconus. In the 2 eye with PLE the ectasia progressed in spite of CXL. Although the results are promissing it is important to keep in mind that they are based on a limited number of patients and follow up to maximum 12 months.
Keywords: keratoconus • radiation damage: light/UV • imaging/image analysis: clinical