Clinical comparison of tear film breakup time measurements in normal dogs using three different methods of fluorescein solution administration.

OBJECTIVE: To evaluate whether the method of fluorescein administration affects the results of tear film breakup time (TFBUT) measurement in normal dogs. ANIMALS STUDIED: Thirty-seven client and hospital staff owned dogs over 1 year of age with no known comorbidities or administration of systemic or topical ophthalmic medications. PROCEDURES: A prospective randomized three-way crossover study was conducted. All dogs received an abbreviated ophthalmic examination to rule out ocular surface disease. Using a 30-min washout interval period, each dog's right eye was received: (a) direct application of fluorescein stain strip with one drop of sterile eyewash, (b) direct application of fluorescein stain strip with two drops of sterile eyewash, or (c) application of one drop from a premade fluorescein solution (dilution of one strip in 0.3 mL sterile eyewash). Eyes were assessed using the cobalt blue filter of a slit lamp biomicroscope. TFBUT measurements were summarized as means ± standard deviation. The methods were compared using mixed model analysis of variance. All analyses were performed using sas version 9.4. RESULTS: Thirty-seven dogs met the inclusion criteria. Mean TFBUT ± standard deviation (SD) for the three described methods were: (a) 16.58s ± 6.9, (b) 15.98s ± 7.1, and (c) 16.43s ± 8.1. No differences between fluorescein stain application techniques were observed (p = .92). CONCLUSION: The technique of fluorescein solution administration did not affect TFBUT measurement in this population of healthy dogs.

Causes, outcomes, and owner satisfaction of dogs undergoing enucleation with orbital implant placement.

OBJECTIVE: To describe clinical and histopathologic pre-operative diagnoses as well as associated post-operative complications following orbital silicone implantation in dogs undergoing enucleation and evaluate owner satisfaction. ANIMALS STUDIED: One hundred and eighty-six dogs who underwent enucleation with orbital implant. PROCEDURES: Medical records from dogs that underwent enucleation with orbital implant performed at Virginia-Maryland Veterinary Teaching Hospital between 2007 and 2019 were reviewed. Owners were surveyed via telephone regarding client satisfaction. RESULTS: Enucleation followed by orbital implant placement occurred in 215 eyes of 186 dogs. The most common pre-operative diagnoses were glaucoma (68.8%), uveitis (17.7%), cataracts (15.8%), intraocular neoplasia (13.0%), and lens luxation (10.7%). The most common histopathologic diagnoses were retinal degeneration (46.5%), uveitis (39.5%), cataract (29.8%), retinal detachment (27.4%), and secondary glaucoma (26.5%). Fourteen eyes (6.5%) from ten dogs had post-operative complications reported including orbit cellulitis (n = 11), implant migration (n = 1), and implant extrusion (n = 1). Five of these dogs (50%) had concurrent diabetes mellitus. Median complication time from surgery was 41 days (range: 11-541 days). Ninety-five owner survey responses were completed with a median time of 6.3 years following surgery. Most owners, 85.3% (n = 81), were satisfied with the post-operative outcome. CONCLUSION: Enucleation with implantation of an orbital implant is a viable and safe method for irreversibly blind eyes. Diabetes mellitus may be a risk factor for the development of post-operative complications. Intraocular neoplasia was not associated with development of post-operative complications. Results of this study indicated high owner satisfaction rates for improving cosmetic appearance after enucleation in dogs.

Descemet's membrane detachments, ruptures, and separations in ten adult horses: Clinical signs, diagnostics, treatment options, and preliminary results.

OBJECTIVE: To describe the clinical presentation, diagnostic imaging results, and treatment outcomes of a series of presumed spontaneous Descemet's membrane detachments (DMD), ruptures, or separations (DMRS) in the adult horse. ANIMALS STUDIED: Ten adult horses of various breeds with DMD or DMRS. PROCEDURES: Descemet's membrane detachments/DMRS were diagnosed via slit lamp biomicroscopy, ultrasound biomicroscopy (UBM), and/or optical coherence tomography (OCT). Penetrating keratoplasty (PK) with heterologous corneal donor tissue (n = 1), superficial lamellar keratectomy, and Gundersen inlay flaps alone (GF, n = 1) or with subsequent intracamerally assisted corneal tissue welding (CTW, n = 2), or CTW alone (n = 5) were performed in 9/10 horses. One horse underwent spontaneous resolution (n = 1). RESULTS: Ten horses were diagnosed with either unilateral DMD (n = 4) or DMRS (n = 6). Seven of ten eyes remained visual during the follow-up period (8.16 ± 6.57 months). Graft transparency was good for the eye treated with PK. The horse that underwent GF alone was functionally blind due to persistent corneal edema. The clinical signs resolved in 3/5 horses that underwent CTW alone, but 2/5 eyes were enucleated due to corneal perforation. Both eyes treated with combined GF/CTW had significant corneal clearing with one having evidence of reattachment on UBM and OCT. CONCLUSIONS: Descemet's membrane detachments separations presents differently than typical DMD and advanced corneal imaging modalities may aid in their diagnosis. Corneal tissue welding using infraCG as the photosensitive agent, or in combination with Gundersen inlay flaps, represents a feasible treatment option for management of equine DMD/DMRS as described in the present case series.

In Situ Gel Formulation for Enhanced Ocular Delivery of Nepafenac.

Nepafenac is a water-insoluble nonsteroidal antiinflammatory drug that is available as an ophthalmic suspension (Nevanac®). Suspensions are undesirable for 2 reasons: they tend to cause foreign body sensation and lacrimation, which could limit residence time and drug bioavailability. This decreases the amount of time the drug has to reach the site of action, the cornea. Previously, we improved the solubility and ocular permeability of nepafenac by complexing the drug with hydroxypropyl-ß-cyclodextrin. In this study, we used the complex to formulate an ion-activated in situ gel system using sodium alginate, Protanal PH 1033, to increase the residence time and to reduce repeat eye drop instillation. Rheological properties of the formulations revealed that the viscosity of the optimized formulation was increased 30-fold when exposed to the simulated tear fluid (35°C). Permeation studies showed that the drug concentration of the in situ formulations were approximately 10 times higher than the commercial product, Nevanac® (p < 0.001). In addition, the in situ gel formulations had 5-fold higher concentrations of nepafenac retained in the cornea when compared to Nevanac® (p <0.001). Finally, ex vivo drug distribution studies in the porcine eye perfusion model revealed a higher drug retention in various ocular tissues such as cornea, sclera, retina, as compared to Nevanac®.

A case of basal cell carcinoma of the nictitating membrane in a dog.

A case of a basal cell carcinoma (BCC) of the nictitating membrane (NM) in a 9-year-old female spayed dachshund is reported. Computed tomography and resection of the NM followed by cryosurgery was performed. Although uncommon, BCC should be considered as a differential diagnosis for tumors of the NM.