SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
Conclusion
CXL offers an alternative treatment for melting ulcerative keratitis, as well as bullous
keratopathy. CXL seems to increase the resistance of corneal tissue to enzymatic
digestion as well as for UVA to kill microbes and thus is a further modality option in
the treatment of microbial keratitis. The free radicals also directly damage
microorganisms and lead to apoptosis of cells in the irradiated area. The riboflavin
may interact with nucleic acids within the microorganisms inhibiting replication.
It is non-invasive, requires less frequent and shorter post-operative care and leads to
substantially less opacities in the cornea compared to tectonic surgical procedures.
This remains a relatively new procedure and more indications and or
contraindications may still be discovered.
References
1.
2.
3.
Famose F. Evaluation of accelerated collagen
cross-linking for the treatment of melting keratitis
in eight dogs. Veterinary ophthalmology 2014;
17: 358 – 367.
Famose F. Evaluation of accelerated collagen
cross linking for the treatment of melting keratitis
in ten cats Veterinary ophthalmology 2015; 18:
95 – 104.
Gallhofer S, Spies BM, Guscetti F et al.
Penetration depth of corneal cross linking with
riboflavin and UV–A [CXL] in horses and
rabbits. Veterinary Ophthalmology 2016; 19:275
– 284.
4.
5.
6.
Hellander–Edman et al. Corneal cross–linking in
9 horses with ulcerative keratitis. Veterinary
Research
2013;
9,
128
http://biomedicalcentral.com/1746-
6148/9/128
Pot SA, Gallhofer NS, Walser–Reinhardt L et al.
Treatment of bullous keratopathy
with
corneal cross–linking in two dogs. Veterinary
ophthalmology 2015; 18: 168 173.
Spies BM, Pot SA, Hafezi F. Corneal collagen
cross linking [CXL] for the treatment of melting
keratitis in cats and dogs: a pilot study.
Veterinary Ophthalmology 2014; 17 1 – 11 .
7] Intracorneal Voriconazole
Should fungal keratitis be suspected or is confirmed via cytology / culture, one would
need to apply topical antifungals every 2-4hrs and the treatment period may last for
weeks to months. This obviously can prove to be a tremendous problem for
management and patient comfort. Fungal abscesses generally have severe
vascularisation which is seen just anterior or posterior to the stromal abscess itself
but seems to fail to invade the abscess. Careful slit lamp biomicroscopy examination
may assist in identifying this subtle situation. It is believed the vascularisation of the
abscess area is very important for the healing process. Studies using intrastromal
voriconazole injections tended to show that blood vessels were attenuated and
healed without extensive vascularisation. This new intrastromal injection approach
seems to be very effective. The current drug of choice is voriconazole [VFend,
Pfizer]. The product can be reconstituted and used as a topical medication by adding
into a dropper bottle or can be injected into the corneal stroma.
Method:
Take a 200mg vial of injectable voriconazole (Vfend I.V., Pfizer Pharmaceuticals,) lyophilised powder
and reconstitute using 3.5 mL of sterile water to obtain 4 ml of clear solution containing 50 mg/ml of
drug. Shake well to ensure it is completely dissolved. It will form a clear solution. The solution is
drawn up into a 1ml tuberculin syringe and transferred in 0.2 ml aliquots to three separate 3ml Luer-
lock syringes. A 27 gauge needle is then attached to each syringe and bent at a 30–45 degree angle
near the hub. The needle is inserted nearly parallel to the corneal surface starting at a point 2–3 mm
abaxial to the near side of the dorsal aspect of the lesion. The needle passes horizontally along
lamellar planes anterior to the abscess to stop just beyond the opposite extent of the lesion. The
voriconazole solution was then injected slowly as the needle was withdrawn. An additional two
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