Evaluation of photoactivated chromophore for keratitis-corneal cross-linking (PACK-CXL) in feline infectious keratitis-patient demographics, treatment protocols, risk factors, and treatment outcome: a retrospective study.

OBJECTIVES: To describe patient demographics and treatment protocols in a population of feline patients undergoing photoactivated chromophore for keratitis-corneal cross-linking (PACK-CXL) as an adjunctive treatment for infectious keratitis. Furthermore, to determine the proportion of PACK-CXL treatment success in the population studied, explore risk factors for treatment failure, and provide recommendations for future PACK-CXL clinical studies. MATERIALS AND METHODS: Records from four veterinary ophthalmology practices were reviewed to identify eligible patients and extract data. Recorded variables included patient-related factors, ocular examination findings, PACK-CXL protocol parameters, and treatment outcome. RESULTS: Records for 153 cats (154 eyes) were included. Median age in the treatment success group was 8 years (interquartile range (IQR) 4-12), with a median ulcer depth of 30% (IQR 30-40). Median age in the treatment failure group was 10.5 years (IQR 4.75-12) with a median ulcer depth of 45.9% (IQR 30-75). Persian cats were the most represented brachycephalic breed (52 out of 64 cats). Modified PACK-CXL protocols were used, including fast energy delivery (134 eyes), and increased fluence (52 eyes). The overall proportion of success was 88% (95% CI 84-93), which was variable between clinics. Eighty-two of 89 mesocephalic cat eyes (92%), and 54 of 65 brachycephalic cat eyes (83%) were classified as treatment successes. CONCLUSIONS: PACK-CXL appeared to be a useful, adjunctive therapeutic modality for the treatment of infectious keratitis in the feline patient population presented here. Brachycephalic cats, older cats, and those with deeper ulcers may be at increased risk for treatment failure.

Use of a porcine urinary bladder acellular matrix for corneal reconstruction in dogs and cats.

OBJECTIVE: To describe the use of a porcine urinary bladder acellular matrix for surgical reconstruction of the cornea in cases of canine and feline deep corneal ulcers, and feline corneal sequestra. MATERIALS AND METHODS: Twenty-seven dogs and three cats with deep corneal ulcers and seven cats with corneal sequestra were included in the study with overall 38 eyes. For each patient, the necrotic material (ie corneal sequestrum or collagenolytic tissue) was removed by circular lamellar keratectomy. The collagen graft was then cut and prepared to match the stromal defect and then sutured into the lamellar keratectomy bed using interrupted and continuous patterns of absorbable polyglactin 9-0 sutures. Postoperative medical treatment consisted of topical and systemic administration of antibiotics, combined with topical administration of atropine sulfate. The animals were examined 18, 45, and 90 days after the surgery. RESULTS: Postoperative examination revealed complete integration of the biomaterial in 93.5% of ulceration cases in both species and in 100% of feline corneal sequestrum cases. In two cases of ulceration (1 dog and 1 cat), progression of the collagenolytic process at the graft periphery required an additional conjunctival graft 7 days after the first surgery. At 90 days post-op, 100% of the eyes were sighted. CONCLUSION: Use of a porcine urinary bladder acellular matrix appears to be effective in the surgical management of deep corneal ulcers and feline corneal sequestra.

Evaluation of accelerated corneal collagen cross-linking for the treatment of bullous keratopathy in eight dogs (10 eyes).

OBJECTIVE: Bullous keratopathy (BK) is a serious corneal condition leading to impaired vision and ocular pain, due to chronic corneal edema and recurrent superficial ulceration. BK is refractory to conventional therapy. In human patients, corneal collagen cross-linking (CXL) has been used for the treatment of BK, and CXL treatment was recently described for canine patients. The aim of this study was to evaluate the clinical and pachymetric effects of accelerated CXL in dogs affected by BK. ANIMAL STUDIED: Eight dogs (10 eyes) with BK underwent accelerated CXL. PROCEDURES: CXL treatment comprised 30 min of riboflavin-dextran instillation, followed by 3 min of UVA irradiation at 30 mW/cm². Ocular pain, corneal edema, corneal ulceration, and pachymetry were evaluated 7, 14, 30, 90, and 180 days after treatment. RESULTS: Corneal ulceration and ocular pain were resolved by 1 week after CXL treatment and did not recur during the 6-month follow-up period. Corneal edema improved in the first 3 months, but worsened from months 3 to 6. Corneal thickness initially decreased, but returned to baseline by 6 months post-CXL. CONCLUSIONS: CXL is a useful treatment option for BK in dogs, despite the short-lasting effects on corneal thickness. Patient comfort improved rapidly after a single procedure, although CXL did not achieve resolution of corneal edema. Treatment protocols may be refined to produce more durable effects on corneal edema.

Evaluation of accelerated collagen cross-linking for the treatment of melting keratitis in ten cats.

OBJECTIVES: Melting keratitis is a serious condition presenting a high risk of permanent blindness and is caused by infectious or noninfectious factors. In humans, the clinical efficacy of collagen cross-linking (CXL) has been described in the treatment of refractory infectious keratitis by arresting keratomalacia. The aim of this study was to evaluate the efficacy of accelerated CXL for the treatment of melting keratitis in cats. ANIMALS STUDIED: Ten cats were treated for unilateral melting keratitis by accelerated CXL. PROCEDURE: Corneas were irradiated by UVA (370 nm) at 30 mW/cm² irradiance for 3 min after soaking with 0.1% riboflavin in 20% dextran for 30 min (D1). Follow-up was conducted 3, 7, 14, and 30 days after treatment. RESULTS: Pain improvement was noted for all cases at D4 examination. Epithelial healing was observed at D8 for 9 of 10 cases and at D15 for 1 of 10 cases. Resolution of cellular infiltration was observed for all cases at D8 examination. The corneal vascularization was reduced for 9 of 10 cats by D31. At D31, all cases presented a variable degree of corneal fibrosis, but all eyes had visual function. No recurrent infection was observed. CONCLUSION: Accelerated CXL appears to be a valuable option for the treatment of melting keratitis in cats. All the cases have reached a satisfactory outcome despite the individual differences in the conditions prior to the CXL treatment and the variable presence of infectious agents.

Assessment of the use of spectral domain optical coherence tomography (SD-OCT) for evaluation of the healthy and pathological cornea in dogs and cats.

PURPOSE: Morphologic evaluation of the cornea is based on the slit-lamp examination. In human ophthalmology, optical coherence tomography (OCT) has opened a new field in the clinical approach to anterior segment disorders and more specifically the cornea. The aim of our study is to describe spectral domain OCT examination of the cornea in dogs and cats in clinical practice conditions. MATERIAL AND METHODS: One hundred eyes were examined from 52 dogs and 41 cats presented to a private practice referral center with an Optovue iVue SD-OCT device. Sixteen healthy animals were used as control group, and the others were examined for various corneal conditions. All animals were examined after sedation or anesthesia. RESULTS: Normal and pathological aspects of canine and feline cornea were described for various conditions such as corneal ulcers, microbial keratitis, corneal sequestrum, infiltrations, foreign bodies, corneal dystrophies, and surgical conditions. CONCLUSION: SD-OCT examination of normal and pathological corneal conditions in dogs and cats gave an accurate evaluation of each component of the cornea. The advantage of the technique is the in vivo, real-time evaluation of all corneal layers with the absence of corneal contact. Constraints included the necessity of sedation for precise focus and the low quality of images obtained with too pigmented or thickened corneas.

Evaluation of accelerated collagen cross-linking for the treatment of melting keratitis in eight dogs.

OBJECTIVE: Melting keratitis is serious condition presenting a high risk of permanent blindness and is caused by infectious or noninfectious factors. In humans, the clinical efficacy of collagen cross-linking (CXL) has been described in the treatment of refractory infectious keratitis by arresting keratomalacia. The aim of this study was to evaluate the efficacy of accelerated CXL for the treatment of melting keratitis in dogs. ANIMAL STUDIED AND PROCEDURE: Eight dogs were treated for unilateral melting keratitis by accelerated CXL. Corneas were irradiated by UVA (370 nm) at 30 mW/cm² irradiance for 3 min after soaking by 0.1% riboflavin in 20% dextran for 30 min. Follow-up was conducted 3, 7, 14, and 30 days after treatment. RESULTS: Pain improvement was observed for all cases within 3 days after treatment. Epithelial healing was observed within 15 days for all cases. Disappearance of cellular infiltration was observed for all cases at day 7. The corneal vascularization disappeared for 4 of 8 dogs and was reduced for 4 of 8 dogs within 1 month. At 1 month, all cases presented a variable degree of corneal scarring, but all eyes had visual function. No recurrent infection was observed. CONCLUSIONS: The main observation of this study is that all the cases have presented with the same clinical result regardless of the presence and the sensitivity of the infectious agents and regardless of the duration of the condition prior to CXL treatment. Accelerated CXL appears to be a valuable option for the treatment of melting keratitis.