Anterior Segment Disease

9/17/13 Corneal Collagen Cross-­‐Linking CCXL-­‐ How It Works l Clinical Indications l Keratoconus l Forme-­‐fruste keratoconus l Post-­‐LASIK ectasia l Post-­‐RK l Pelliucid Marginal Degeneration l Cornea is saturated with riboflavin l Cornea is exposed to UV light l Photosensitization occurs, singlet oxygen released l The molecular oxygen causes extra cross-­‐linking of corneal collagen fibers and extracelluilar matrix proteins l This causes corneal stiffening CCXL – The Procedure CCXL Post –op Process l Debridement of central 7-­‐9mm of epithelium l Riboflavin 0.1% is applied and allowed to saturate cornea for 30 minutes l Cornea is irradiated with 370-­‐nm wavelength light for 30 minutes, riboflavin is reapplied every 5 minutes throughout the procedure l Topical antibiotic ointment and bandage CL applied l Monitor post-­‐op healing closely l Much like PRK post-­‐op l Watch for infection – antibiotic l Mitigate corneal haze – steroid l Moderate pain-­‐ NSAID l Final result may not be seen until 18 months out, so refraction may vary Some CCXL Particulars CCXL Benefits l Cornea must be saturated before UV light application l 90% of the UV light absorbed within the anterior 400 microns of K l Riboflavin blocks deeper light penetration thus avoiding cytotoxicity at endothelium or lens capsule l Effect is not immediate, 3-­‐6 months for new keratocytes to repopulate and remodel cornea l Improvement continues over 15 month period l Improved regularity to corneal shape l Decreased apical scarring l Improved UCVA and BCVA l Decreased astigmatism l Improved ability to wear CL l Improve outcomes with secondary ICCL l CCXL definitely works better on early diagnosed keratoconic pxs! 6