Corneal collagen cross‐linking as treatment for infectious and noninfectious corneal melting in cats and dogs: results of a prospective, nonrandomized, controlled trial

Abstract

OBJECTIVE. UV-A/Riboflavin crosslinking of corneal collagen fibers (CXL) is a highly promising therapy for corneal melting in humans. A prospective interventional, non-randomized, controlled study was conducted to compare the stabilizing effect of CXL treatment on melting keratitis in dogs and cats and the complication rate of CXL to those of standardized intensive medical treatment. PROCEDURES. Forty-nine eyes with melting keratitis were included in the study between October 2009 and October 2012. All eyes were treated according to the same medical treatment protocol. Nineteen eyes were CXL-treated and 30 eyes were not. Follow-up included slit-lamp examination, fluorescein staining, ulcer size measurement, stromal stability evaluation, photographic documentation and documentation of complications. RESULTS. Five of 19 eyes in the CXL group and 9/30 eyes in the control group required rescue stabilization due to continued melting. Seven of the 9 control group corneas stabilized after rescue CXL treatment. At initial presentation, the ulcers in the canine CXL group were significantly deeper and larger than in the control group. Ulcer deepening during follow-up was more pronounced in the canine control group than in the canine CXL group. CXL treatment related complications were not observed. CONCLUSIONS. Based on the similar failure rates in the control and CXL treatment groups despite the poorer initial situation in the CXL group, the tendency for the ulcers in the control group to deepen and the stabilization of all corneas receiving CXL rescue treatment, we believe that CXL has its place as an adjunctive therapy for melting keratitis in veterinary ophthalmology. RESULTS.Five of 19 eyes in the CXL group and 9/30 eyes in the control group required 39 rescue stabilization due to continued melting. Seven of the 9 control group corneas stabilized 40 after rescue CXL treatment. At initial presentation, the ulcers in the canine CXL group were 41 significantly deeper and larger than in the control group. Ulcer deepening during follow-up 42 was more pronounced in the canine control group than in the canine CXL group. CXL 43 treatment related complications were not observed. 44 CONCLUSIONS. Based on the similar failure rates in the control and CXL treatment groups 45 despite the poorer initial situation in the CXL group, the tendency for the ulcers in the control 46 group to deepen and the stabilization of all corneas receiving CXL rescue treatment, we 47 believe that CXL has its place as an adjunctive therapy for melting keratitis in veterinary 48 ophthalmology. 49

Outcome of medical therapy for keratomalacia in dogs

“…This outcome is notably lower than that previously reported by Pot et al . () (18/26) and, although there is no objective way to compare the severity of the lesions between that and the current study, it appears that the clinical findings in these two reports are very similar. The main difference is in collagenase inhibitor therapy protocols, since oxytetracycline ointment, K‐EDTA drops, serum drops and systemic doxycycline were used by Pot et al .…”

“…The main difference is in collagenase inhibitor therapy protocols, since oxytetracycline ointment, K‐EDTA drops, serum drops and systemic doxycycline were used by Pot et al . (), whereas we used equine serum only. Since these various compounds utilise different mechanisms to inhibit proteases, the combination of several protease inhibitors might have been beneficial, as previously suggested (Ollivier ).…”

“…The criteria for inclusion were: (1) a clinical diagnosis of keratomalacia/“melting” corneal ulcer – based on subjective evaluation (changes in corneal contour and ulcer depth, changes in perceived stability of the stroma (gelatinous), cellular infiltrates and malacic corneal material in the ulcer area) as commonly described in veterinary reports (Famose , Pot et al . ); (2) intensive topical treatment with frequent administrations of tobramycin in combination with equine serum (each 2 to 4 hours) applied by the owner or by the staff of the intensive care unit; and, (3) return for follow‐up examinations. Cases with a different intensive medical treatment protocol or inadequate drug therapy (due either to owner inability to deliver the frequent topical administrations or poor dog compliance) were excluded from the study.…”

“…In a prospective study by Pot et al ., eight of 26 canine ulcers with keratomalacia treated under an intensive medical treatment protocol required rescue stabilisation due to progressive keratomalacia (Pot et al . ). No association between clinical findings and treatment failure was reported (Pot et al .…”

Keratomykose beim Pferd

“…Eine neue und sehr interessante Behandlungsmöglichkeit, die ursprünglich zur Therapie des Keratokonus und aktuell auch gegen infektiöse Hornhautentzün-dungen eingesetzt wird, ist die CXL-Technik (corneal Collagen Crosslinking -CXL) [8,12]. Bisher wurden jedoch zu wenige Pferde mit dieser Technik behandelt, um die Ergebnisse objektiv beurteilen zu kön-nen.…”