Pyogenic granuloma of the cornea in a pony: Uncommon complication of corneal wound healing.

A 6-year-old miniature Shetland pony mare was referred for evaluation of a left corneal mass, which developed from the healing tissue of a corneal traumatic ulceration that had occurred 4 weeks previously. On gross examination, a spherical, smooth-surfaced, and pink-colored lesion of about 1 cm in diameter was protruding from the left palpebral fissure. Ophthalmic examination revealed that it was attached to the scar tissue of the cornea, and that one corpora nigra was adherent to the posterior face of corneal wounded area, without sign of uveitis. The remainder of the ophthalmic examination was unremarkable. The mass was excised, and cryotherapy was used as an adjunctive therapy. Histopathology of the resected mass was consistent with a pyogenic granuloma on the basis of radially oriented proliferating capillaries, embedded in immature granulation tissue containing an infiltrate of neutrophils, plasma cells and eosinophils. There were no histological features of malignancy. 2 months after surgery, the ventral part of the fibrotic corneal scar was slightly raised by a pink tissue, suggesting possible recurrence of the initial lesion. A second cryotherapy was performed over the leukoma area. No recurrence has been noted for a follow-up period of more than 25 months. Pyogenic granuloma is a benign proliferative fibrovascular response that typically develops after trauma or surgery. Corneal involvement is rare in humans, and to the authors' knowledge has never been documented in veterinary ophthalmology.

Conjunctival calcinosis circumscripta in a dog: Treatment combining surgical resection and amniotic membrane grafting.

This report describes the clinical features, histopathology, and surgical treatment of a case of conjunctival calcification in a 5-month-old female English Setter, referred with a history of recurrent conjunctivitis in the right eye (OD). The ophthalmic findings were limited to multifocal white plaques embedded in a markedly inflamed conjunctiva of the eyelids and the anterior nictitating membrane OD. Calcification was suspected. The blood cell count, blood chemical profile, and urinalysis were within normal limits, and long-bone radiographs appeared normal. After removal of the affected area by means of a large conjunctivectomy, cryopreserved canine amniotic membrane (AM) was transplanted to fill in the defect. Multifocal ectopic calcium deposits in the conjunctival lamina propria were confirmed histopathologically. The postoperative healing was uneventful, and no recurrence was observed during a follow-up period of five years. Conjunctival mineralization is uncommon in canine ophthalmology, and the cause remained undetermined in the present case, for which AM transplantation was able to promote conjunctival healing after a large surgical excision.

Corneal anesthesia associated with topical application of 2% lidocaine nonophthalmic gel to healthy canine eyes.

OBJECTIVE: To assess the degree and duration of corneal anesthesia induced by topical application of 2% lidocaine gel to the healthy canine eye. ANIMALS: Nineteen adult Beagles free of ocular abnormalities. PROCEDURES: Baseline corneal touch threshold (CTT) was measured bilaterally with a Cochet-Bonnet aesthesiometer. The 2% lidocaine gel (0.1 mL) was applied to one eye, randomly assigned, and the same volume of a lubricant gel was applied to the opposite eye. The CTT measurements were repeated bilaterally within 1 minute, after drug application, and every 5 minutes, until the baseline corneal sensitivity was restored. The potential for local adverse effects was evaluated. RESULTS: Complete desensitization of the cornea (CTT = 0) was achieved one minute after lidocaine gel application and was maintained during 25.3 ± 12.5 minutes. Overall, the corneal sensitivity was significantly decreased for 58.4 ± 16.6 minutes compared with baseline level. Minor and reversible punctate epithelial erosions of the cornea were observed in the two treatment groups and were attributed to the anesthetic effect and the aesthesiometry procedure. CONCLUSIONS: In the current study, the 2% lidocaine gel provided a sustained, deep and well-tolerated corneal anesthesia in ophthalmically normal dogs.

Preliminary study of the safety and efficacy of medium-chain triglycerides for use as an intraocular tamponading agent in minipigs.

PURPOSE: To date, only silicone oils and gases have the appropriate characteristics for use in vitreo-retinal surgery as vitreous substitutes with intraocular tamponading properties. This preliminary study evaluated the safety and efficacy of medium-chain triglycerides (MCTs) for use as a tamponading agent in minipigs. METHODS: In 15 minipigs, 15 right eyes underwent vitrectomies followed by injection of MCT tamponade (day 1). Two groups were defined. In Group A (ten eyes), the surgical procedure before MCT injection included induced rhegmatogenous retinal detachment (RRD), retina flattening, and retinopexy. In Group B (five eyes), MCT was injected without inducing RRD; in these eyes, MCT was removed on day 90. Pigs were sacrificed on day 45 (Group A) or 120 (Group B). Eyes were examined on days 1, 5, 15, and 45 in both groups and on days 90 and 120 in Group B. In Group B only, we performed bilateral electroretinography examinations on days 1 and 120, and histological examinations of MCTs and controlateral eyes were performed after sacrifice. RESULTS: In Group A eyes (n = 9; one eye was non-assessable), on day 45, the retina was flat in seven eyes and two RRD detachments were observed in insufficiently MCT-filled eyes. In Group B, electroretinography showed no significant differences between MCT eyes and controls on days 1 or 120. Histological analyses revealed no signs of retinal toxicity. CONCLUSIONS: This study showed that MCT tamponade seems to be effective and safe; however, additional studies are needed before it becomes commonly used as a tamponading agent in humans.

Choroidal melanocytoma in a cat.

An 11-year-old male, neutered European cat was presented for anisocoria due to pupillary dilation in the right eye. Ophthalmic findings were restricted to this eye and consisted of a raised, darkly pigmented, retrolental mass associated with retinal detachment. Ultrasonography identified the mass lesion protruding into the vitreous cavity from the posterior pole of the eyeball and confirmed the detachment of the retina. A tentative diagnosis of an intraocular tumor was made. Radiographic evaluation and retromandibular lymph node cytology did not reveal evidence of distant metastasis. Orbital exenteration of the affected eye was performed and the tumor was diagnosed as a choroidal melanocytic tumor with no criteria of malignancy (melanocytoma). The cat died 5 months later from renal lymphoma, and necropsy did not detect metastasis of the melanocytic tumor. To our knowledge this is the first reported case of feline choroidal melanocytoma.

Keratoprosthesis with retrocorneal fixation: preliminary results in dogs with corneal blindness.

OBJECTIVE: To evaluate the use and complications of a penetrating keratoprosthesis implantation in the management of corneal opacification in dogs. METHODS: A retrospective clinical study describes the indications for the surgical technique utilized and the outcomes of this procedure in 20 eyes of 19 dogs with blindness of corneal origin. A successful surgical outcome was defined as a clear keratoprosthesis optic and improvement or restoration of functional vision over a follow-up period ranging from at least 8 months to a maximum of 7 years. RESULTS: Eyes with total corneal opacification resulting from chronic superficial keratitis (n = 11), keratoconjunctivitis sicca (n = 5), endothelial dystrophy (n = 3) and chemical burn (n = 1) were treated by unilateral (n = 18) or bilateral (n = 1) full-thickness implantation of a keratoprosthesis. Keratoprostheses were retained in 15 eyes (75%) which regained vision to the date of reporting. Among these eyes, six had uncomplicated postoperative course, five developed retroprosthetic membranes and four developed granulation tissue over the optic of the keratoprostheses. These complications were successfully removed surgically in the nine eyes. The five remaining eyes (25%) developed serious early postoperative complications, for which enucleation had to be performed. CONCLUSION: In keratopathies in which the corneal opacification could not be treated by standard medical or surgical procedures, this keratoprosthesis appears to be promising to restore vision in chronic superficial keratitis and deep corneal dystrophy. It appears to have a poor prognosis in keratoconjunctivitis sicca in brachycephalic dogs. The post operative complications retro-prosthetic membranes and granulomatous overgrowth could be treated well.

Congenital orbital cysts of neural tissue in two dogs.

A 3-month-old English Cocker Spaniel and a 6-month-old miniature poodle presented with clinical signs related to an abnormal right eye since birth. In both dogs, the right globe could not be identified and was replaced by a fluctuant intraorbital mass covered by a vascularized mucous membrane. Ultrasonography demonstrated that both masses were cystic structures markedly larger in size than the normal contralateral globes. In both cases, surgical excision revealed a multilobular cyst filling the whole orbital cavity. Histopathologic examination and immunostaining for glial fibrillary acid protein and S100 protein supported a diagnosis of neural cysts associated with ocular dysplasia. The definitive diagnosis was congenital cystic eye and microphthalmos with cyst for the Cocker Spaniel and miniature poodle, respectively. Karyotype was normal in both dogs. Congenital cystic eye and microphthalmos with cyst result from defects in early embryonic life that arise following formation of the optic vesicle and prior to closure of the optic fissure. To the authors' knowledge neither has been reported in the canine species. They should be considered in the differential diagnosis of orbital cysts in dogs.

Comparative effect of alfuzosin and tamsulosin on the contractile response of isolated rabbit prostatic and iris dilator smooth muscles: possible model for intraoperative floppy-iris syndrome.

PURPOSE: To compare the pharmacologic properties of tamsulosin and alfuzosin in isolated prostatic and iris dilator smooth muscle from pigmented rabbits. SETTING: UROsphere Laboratories, Université Paul Sabatier, Toulouse, France. METHODS: Prostatic and iris dilator smooth muscle strips were placed in organ baths. A concentration-response curve to phenylephrine was compared before and after incubation with tamsulosin or alfuzosin. RESULTS: Both drugs were approximately 30 times less potent in iris dilator than prostatic smooth muscle. In the iris, tamsulosin acted as a competitive antagonist starting at the 0.03 microM concentration (pA(2)=7.96). This is in the same range as the maximum plasma concentration after a 0.4 mg dose of tamsulosin in humans (0.025 microM). The antagonistic effect of alfuzosin in the iris was weaker (calculated mean pA(2) value of 5.63+/-0.19). Concentrations with an equipotent antagonistic effect on rabbit iris dilator muscle (3.0 and 10.0 microM) were approximately 100 to 300 times higher than the maximum plasma concentrations after a 10.0 mg dose of alfuzosin in humans (0.032 microM). CONCLUSIONS: Tamsulosin was more effective than alfuzosin at blocking adrenergic contraction of the iris dilator muscle in pigmented rabbits. Both drugs were less potent in the iris than in the prostate, which suggests that an additional iris receptor could be involved. If valid in humans, our results suggest that attainable plasma concentrations of tamsulosin are able to antagonize iris dilator smooth muscle contraction, whereas those of alfuzosin are not. This could explain the higher frequency of intraoperative floppy-iris syndrome in patients treated with tamsulosin than with alfuzosin.

Comparison of cytologic and histologic evaluations of the conjunctiva in the normal equine eye.

OBJECTIVE: To describe the cells observed in conjunctival brush cytology (CBC) from normal horses and compare these findings with conjunctival structural histology so as to understand which cells are recovered from CBC. METHODS: This study was divided into three parts. (1) Conjunctival brush smears were collected from 20 healthy horses on both eyes and a differential count on 300 cells was carried out on May Grünwald-Giemsa (MGG) smears. (2) A similar protocol was used for whole eyes from five horses obtained rapidly after death from a slaughterhouse. The eyes were then assessed for conjunctival histology. (3) Cytobrush smears were collected from five healthy horses. Smears were examined after MGG or periodic acid Schiff (PAS) staining. RESULTS: The differential cell count showed a majority of deep and intermediate epithelial cells with very few superficial and goblet cells in both eyes. A stratified columnar to cuboidal epithelium was observed on nearly the whole surface of the conjunctiva. A stratified squamous type was observed at the palpebral and bulbar edges. Areas with highest mucus cell indices were found from the nasal to the temporal edge of the equine inferior conjunctiva in the upper palpebral segment near the fornix and in a part of the nasal fornix. In MGG smears no mucus cells were identified; however, they were numerous in PAS smears (22.6% +/- 11) and were mostly cylindrical cells (42.5% +/- 14.4 PAS positive). CONCLUSIONS: Cytobrush smears in the healthy horse are characterized by a majority of polyhedral and cylindrical cells and a few squamous cells. The cylindrical cells may be mucous cells and probably originate from the main stratified columnar to cuboidal epithelium.

Multiple eyelid apocrine hidrocystomas in two Persian cats.

Abstract Two middle-aged Persian cats were presented for evaluation of periocular masses. On examination, multiple pigmented nodules, 2-10 mm in diameter, were found in the periocular skin. Excisional biopsy revealed unilocular cystic lesions derived from apocrine sweat glands and resembling apocrine hidrocystomas of the eyelids described in humans. Immunostaining for Ki67 identified actively proliferating epithelial cells and demonstrated, for the first time, that these cystic lesions are adenomatous proliferative tumors (cystadenomas) rather than retention cysts. In both cases, additional lesions appeared within 6 to 9 months at affected and previously unaffected sites on the eyelids.

Population pharmacokinetics of marbofloxacin in aqueous humor after intravenous administration in dogs.

OBJECTIVE: To evaluate, by use of population pharmacokinetics, the disposition of marbofloxacin in the aqueous humor after IV administration in dogs and identify its potential usefulness in the prophylaxis and treatment of intraocular infection. ANIMALS: 63 dogs. METHODS: Dogs received a single dose of marbofloxacin (2 mg x kg(-1), IV) at various time intervals before cataract surgery. Aqueous humor and blood samples were collected at the beginning of surgery. Marbofloxacin concentrations were measured by high-pressure liquid chromatography. Data were analyzed with a nonlinear mixed-effect model and, by use of population pharmacokinetic parameters, the time course of aqueous humor concentration was simulated for single doses of 3, 4, and 5.5 mg x kg(-1) IV. Pharmacodynamic surrogate markers and measured aqueous humor concentrations were used to predict in vivo antimicrobial activity. RESULTS: A maximum marbofloxacin concentration of 0.41 +/- 0.17 microg x mL(-1) was reached in the aqueous humor 3.5 hours after IV administration. In the post-distributive phase, marbofloxacin disappeared from aqueous humor with a half-life of 780 minutes. The percentage penetration into the aqueous humor was 38%. Predictors of antimicrobial effects of marbofloxacin (2 mg x kg(-1), IV) indicated that growth of the enterobacteriaceae and certain staphylococcal species would be inhibited in the aqueous humor. Marbofloxacin administered IV at a dose of 5.5 mg x kg(-1) would be predicted to inhibit growth of Pseudomonas aeruginosa and all strains of staphylococci but would not eradicate streptococcal infections. CONCLUSIONS AND CLINICAL RELEVANCE: Marbofloxacin administered IV can penetrate the aqueous humor of canine eyes and may be suitable for prophylaxis or treatment of certain anterior chamber infections.