esvo_sferov_corneal-cross-linking_technique_and_veterinary applications_ frank-famose
TRANSCRIPT
CXL*Corneal collagen- cross-linking for veterinarians
* Collagen Cross-Linking
Dr Frank FAMOSE – [email protected] October 6th, 2016
Collagen reticulation by cross-linkingA natural…
or industrial… … or medical process
Collagen reticulation
Anti-infectious effects
Keratocytes apoptosis
The photochemical process
The Dresden protocol
A recent breakthrough…
The CXL in human ophthalmology
Corneal ectasia:Progressive keratoconusPost-LASIK ectasiaPellucid marginal deg.
Infectious keratitis:PACK-CXL
Bullous keratopathy
The CXL in veterinary ophthalmology
Infectious keratitis(dogs, cats, horses)
Bullous keratopathy(dogs)
Keratomalacia« corneal melting »
MMP imbalance
Perforation
Antibiotics& anticollagenases
Tectonic surgery
CXL
Results*
8 dogs 10 cats
*Accelerated cross-linking
D1 D31
8/8 dogs – 10/10 cats 2/8 dogs – 3/10 cats
Corneal vascularization
Corneal scar
D1 D31
8/8 dogs – 10/10 cats
Discussion
Clinical and pain improvement Direct effects of UVA
Free oxygen radicals
Physical changes withinthe cornea
Biological corneal response
Adverse effects ?
Infections
Herpesvirus reactivation
Endothelial alterations
In humans
No adverse effects attributableto the treatment
Ulcerative keratitis in Horses(Dr Hellander-Edman)
9 cases Ulcerative keratitis(Dresden protocol)
8 good results (1-3 months)
1 enucleation (fungalkeratitis)
Worse than dogs and cats ?
Corneal /epithelial thickness
Depth of infection
Low power UVA
RF administration?
Protocol modifications
ConventionalProtocol
Modifications"Epi-On"
"Epi-Off"(epithelialremoval)
UV exposition3mW/cm² - 30 min.
(5,4J/cm²)
Riboflavininstillation
(30 minutes)
Low or highosmolarity RFNanostructures,adjuvants
Intrastromal injectionsIontophoresis
AcceleratedCXL9-30mW/cm²
(5,4J/cm²)
Epithelium RF distribution UVA irradiation
Standard or accelerated ?
Standard3 mW/cm²30 minutes
« Flash »30 mW/cm²3 minutes
5,4 J/cm²
Total durationab. 1h20
Total durationab. 40 min
Same biologicaleffects ?
Same energylevel
Iontophoresis
Use of a low intensity continuous electric current to enhance the penetration of a ionized substance through a biological tissue
2013Iontophoresisof RF forCXL(keratoconus)
From 1990
SteroidsAntibioticsAntifungal
AntimetabolitesOligonucleotides
DiscoveryWirz 1908
No veterinaryclinical use
(Bikbova et al.Mastropasqua et al.Touboul et al.)
No data forkeratitis
treatment
IontophoresisSame therapeuticeffects (keratitis)
Bullous keratopathy
Endothelial alterations
Corneal edema
Bullae and epithelial ulcers
« Epi-off » Stromalcompaction UVA irradiation
Hyperosmotictopical drugs
RF +Dextran 20 %
9 mW/cm²10 minutes
Bullous keratopathy
Results
Epithelial healing (<1 sem)
ConclusionMain indication : infectious keratitis
2 main constraints- High fluence- Minimal corneal thickness
Secondary indication: Bullous keratopathy
Merci
