Instructional course IC 1 Corneal cross linking therapy: Operative technique Auhor: Kristina Mikek, Slovenia Co. Authors : Carina Koppen, Belgium Zoltan Nagy, Hungary David O Brart, UK

Preoperative assessment Patient counseling The role of epithelial removal Riboflavin dosage regimens UVA exposure regimens UV lamps and calibration Postoperative care and follow up Complications K. Mikek

Process of corneal cross linking Patient is referred to your service Preoperative diagnosis Decision on therapeutic intervention Treatment procedure Corneal cross linking therapy Post operative follow up visits K. Mikek

Preoperative diagnosis Measurements performed outside of your ophthalmology department and/or refractive changes given from the patient can not serve as a basis for a treatment decision Before final decision for cross linking treatment some check up examinations – depends on progression of the disease Family history of keratoconus or progression of keratoconus K. Mikek

Preoperative examination Rigid contact lenses must be removed for at least 2 weeks to achieve reasonable measurements of the cornea Most patients with keratoconus who came for the treatment don’t wear contact lenses because they have problems with them K. Mikek

Preoperative examination Refraction Visual acuity Slit lamp examination (cornea, lens and retina) Specular microscopy – morphology of endothelial cells and density Corneal topography and Sheimpflug images Corneal thickness map K. Mikek

Is the patient for cross linking treatment? Progression of ectasia verified by corneal topography – change of max K by > 1 Dpt Age of the patient – corneal changes? Can the patient expect any benefit from corneal cross linking treatment – CL tolerance, visual performance? K. Mikek

Is the patient for cross linking treatment? Are there any risk factors that might lead to unpleasant healing responses and complications after treatment – rheumatism, keloid formation, pregnancy, dry eyes…? Is the corneal thickness suitable for treatment, do I have to swell the cornea? K. Mikek

What we have to explain to the patient before treatment? Postoperative follow up time and hazy vision in the first 1 to 2 weeks after the cross linking treatment Some pain and photophobia on the day of surgery Results of stability statistically proven on the long term Based on the preoperative examination: Real expectation regarding the visual acuity (do not promise to the patient!) K. Mikek

Treatment procedure Calibration of the UV cross linker: To get the right energy to the cornea To avoid “hot spots” on the cornea and possible complications Wollensak G, Spoerl E, Seiler T. Am J Ophthalmol 2003 K. Mikek

Treatment procedure Topical anesthetic eye drops and pilocarpin at the time of surgery Partial epithelium removal – abrasio (diameter 8 to 9mm) Brush, 20% of ethanol, lines or punctures in the epithelium Applying riboflavin 1 drop every 2 min for 30 min Slit lamp inspection – blue light: staining of the anterior chamber Start UV- illumination with UV cross linking device: 1 drop of Ribo every 2 min for 30 min K. Mikek

Treatment procedure At the end of surgery therapeutic contact lens is placed on the surface of the cornea Eye drops at the end of surgery: 0,1 % prednisolon Ciprofloxacin K. Mikek

Postoperative treatment: 0,1% prednisolon 3 times/day Ciprofloxacin 4 times/day Artificial tears hourly Besides this: Pain killers - among these Lyrica, which helps the most Removing of the contact lens: 3 rd postoperative day K. Mikek

Treatment procedure Based on animal experimental studies and clinical studies the following parameters are the most appropriate for maximal safety of cross linking treatment: Corneal deepithelization (diameter 8 to 9 mm) 0,1% riboflavin in 20% dextrane – swelling the cornea if the corneal thickness after abrasio is less than 400 microns with riboflavin hypotonic solution! 3mW/cm2 at 365 nm for 30 min K. Mikek

Cross linking – cause of action Riboflavin diffusion UV –light illumination and absorption Formation of oxygen radicals Chemical reactions and cross link formation Changes of the biomechanical properties of the cornea M.Mrochen, IV.international congress of corneal cross-linking, 2008 K. Mikek

Background of corneal cross linking Molecular level – collagen molecules Microscopic level – collagen fibrillae of linked collagen molecules Tissue level – collagen lamellae – parallel arrangement of the fibrillae Organ level – cornea –arrangement of interlaced collagen lamellae M.Mrochen, IV.International Congress of Corneal Cross-linking, 2008 K. Mikek

Complications Delayed corneal reepithelization Drop of the therapeutic CL out of the treated eye and infection Corneal endothelium cell damage – in thin corneas Keratouveitis Very seldom severe corneal haze K. Mikek

Conclusions Corneal collagen cross-linking is now the only treatment which could stop the progression of keratoconus or iatrogenic ectasia of the cornea Complications rate of the treatment is low and mostly treatable or not affecting the visual acuity: With careful counseling of the patients before treatment and following the guidelines for cross linking treatment ! K. Mikek

Thank you. K. Mikek