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:
 3rd 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
K. Mikek
M.Mrochen, IV.international congress of corneal cross-linking, 2008
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.
kmikek@morelaokulisti.si
www.morelaokulisti.si
K. Mikek