Systemic absorption and gastrointestinal adverse effects from topical ketorolac and diclofenac ophthalmic solutions in healthy dogs.

OBJECTIVE: To investigate systemic absorption and gastrointestinal (GI) adverse effects of topical ketorolac 0.5% and diclofenac 0.1% ophthalmic solutions. ANIMALS: 11 healthy purpose-bred Beagles. METHODS: Dogs were randomly assigned to receive either ketorolac (n = 6) or diclofenac (5), 1 drop in both eyes 4 times daily for 28 days. Upper GI endoscopy was performed on days 0 and 29 with mucosal lesion scores (0 to 7) assigned to each region evaluated. Plasma samples were collected on days 14, 21, and 28 for measurement of diclofenac and ketorolac using high-performance liquid chromatography-mass spectrometry. RESULTS: GI erosions and/or ulcers developed in all ketorolac-treated dogs and 1 of 5 diclofenac-treated dogs. Post-treatment mucosal lesion score for the antrum was higher in the ketorolac group than in the diclofenac group (P = .006) but not significantly different for any other region. Post-treatment antral mucosal lesion scores were significantly related to plasma ketorolac concentrations (P < .001). Ketorolac and diclofenac were detected in the plasma at all time points (median ketorolac day 14, 191 ng/mL; day 21, 173.5 ng/mL; and day 28, 179.5 ng/mL; and median diclofenac day 14, 21.1 ng/mL; day 21, 20.6 ng/mL; day 28, 27.5 ng/mL). Vomiting and decreased appetite events were observed uncommonly and were not significantly different between treatment groups. CLINICAL RELEVANCE: GI ulceration and erosion developed after ophthalmic administration of ketorolac and diclofenac, with higher plasma concentrations and more severe GI lesions associated with ketorolac. Clients should be alerted to this potential risk with ophthalmic use and informed to watch for systemic clinical signs that would warrant veterinary reevaluation.

Retrospective evaluation of the incidence of gastrointestinal bleeding in dogs receiving ophthalmic nonsteroidal anti-inflammatory drugs.

OBJECTIVES: To report the incidence of gastrointestinal (GI) bleeding and associated risk factors in a population of dogs receiving ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs). ANIMAL STUDIED: Medical records of dogs prescribed ophthalmic NSAIDs (cases), dogs receiving systemic NSAIDs alone and dogs receiving systemic prednisone alone (controls). PROCEDURES: Data were collected retrospectively from the medical records of 204 dogs prescribed ophthalmic NSAIDs (diclofenac, ketorolac, or flurbiprofen), which were subdivided based on if they received any concurrent systemic NSAIDs or glucocorticoids, 136 dogs receiving a systemic NSAID (carprofen or meloxicam) alone, and 151 dogs receiving a systemic glucocorticoid (prednisone) alone at a referral hospital from 2015 to 2019. RESULTS: Gastrointestinal bleeds developed in 8/79 (10.1%) of topical NSAID-only cases, 10/136 (7.4%) of systemic NSAID controls, and 14/151 (9.3%) of systemic glucocorticoid controls, with no significant difference between the three groups (p = .6103). There were no significant differences in GI bleed rates between cases treated with ketorolac, diclofenac, or flurbiprofen (p = .160), although severe GI bleeding was only seen in ketorolac-treated dogs. Presence of a known concurrent risk factor for GI bleeding was significantly associated with the development of GI bleed in dogs on ophthalmic NSAIDs (p = .032). CONCLUSIONS: Dogs treated with ophthalmic NSAIDs developed GI bleeding at a frequency comparable to dogs receiving systemic NSAIDs or systemic glucocorticoids alone, suggesting that dogs receiving ophthalmic NSAIDs may be at increased risk of GI bleeding.

Increased drug concentration and repeated eye drop administration as strategies to optimize topical drug delivery: A fluorophotometric study in healthy dogs.

OBJECTIVES: Determine tear film kinetics with different fluorescein concentrations and repeated eye drop administration at various time intervals. ANIMALS STUDIED: Six healthy Beagles. PROCEDURES: Six experiments were conducted on separate days: single eye drop administration (control) or two separate eye drops administered at 30 s, 1, 2, 5, and 10 min intervals. For each experiment, one eye received 0.3% fluorescein solution while the other eye received 1% fluorescein solution, and tear fluid was collected with capillary tubes at 0, 1, 5, 10, 20, 30, 40, 50, 60, 90, 120, and 180 min. Fluorescein concentrations were measured using automated fluorophotometry. RESULTS: Compared with 0.3% solution, eyes receiving 1% fluorescein solution had significantly higher tear film concentrations (p ≤ .046) and the area-under-the-fluorescein-time curve was twofold greater (p = .005). Compared with control: (i) Tear film concentrations were significantly higher for up to 20 min when repeating administration 30 s to 5 min after the first drop (p ≤ .006); (ii) The highest increase in area-under-the-curve was obtained with 2 and 5 min intervals for 0.3% (+109%-130%) and 1% solutions (+153%-157%); (iii) The highest increase in median precorneal retention time (defined as tear film concentration < 5% from baseline values) was obtained with 5 min intervals for 0.3% (55 min vs. 15 min in control) and 2-5 min intervals for 1% solutions (50 min vs. 25 min in control). CONCLUSIONS: Drug delivery to the ocular surface can be enhanced by using more concentrated formulations and/or by repeating eye drop administration 2-5 min after the first dose.

Incidence of concurrent systemic injuries with traumatic proptosis and its effect on outcome - 100 dogs.

Objective: To evaluate the incidence of concurrent systemic injuries in dogs with traumatic ocular proptosis and their effect on survival to discharge. Additionally, to evaluate for associations between the type of trauma, each presenting vital signs, minimum laboratory database findings including packed cell volume, total solids, plasma glucose and lactate concentrations, and the diagnosis of concurrent systemic injury and survival. Design: Retrospective study between the years 2017 and 2022. Setting: One university teaching hospital and one large, private practice. Animals: One hundred dogs presenting to the hospital with a diagnosis of traumatic ocular proptosis. Measurements and main results: Medical records were retrospectively reviewed; signalment, breed, sex, age, weight, date of presentation, type of trauma sustained, time from trauma to presentation, vitals on presentation, and minimum laboratory database findings including packed cell volume (PCV), total solids (TS), plasma glucose concentration, and plasma lactate concentration were recorded. A modified animal trauma triage (ATT) score was retrospectively calculated. A total of 17 dogs (17%) had concurrent systemic injury. Compared to dogs without systemic injuries, dogs with systemic injuries had a significantly lower body temperature [median 101.1F (38.3C) vs. 101.6F (38.6C); P = 0.008], significantly higher plasma glucose concentrations (125 mg/dL, 6.9 mmol/L vs. 112 mg/dL, 6.2 mmol/L; P = 0.012) and approaching statistical significance, lower PCV values (median 40 vs. 46%; P = 0.051). Conclusions: Dogs presenting with traumatic ocular proptosis do present with concurrent systemic, non-ocular injuries; however, these concurrent injuries do not seem to be associated with survival to discharge.

Impact of multi-drug resistance on clinical outcomes of dogs with corneal ulcers infected with Staphylococcus pseudintermedius.

Objective: Compare characteristics and clinical outcomes of dogs with infectious keratitis from Staphylococcus pseudintermedius considered to be multidrug-resistant (MDR) or not. Procedures: Staphylococcus pseudintermedius isolated as the primary pathogen from canine patients with ulcerative keratitis were considered MDR if resistant to at least one agent in three or more classes of antibiotics. Medical records were reviewed for history, patients' characteristics, clinical appearance, therapeutic interventions, and clinical outcomes. Results: Twenty-eight dogs (28 eyes) were included. Compared to non-MDR cases, MDR diagnosis was significantly more common in dogs with recent (≤30 days) anesthesia (7/15 vs. 1/13, P = 0.038) and more common in non-brachycephalic dogs (8/15 vs. 2/13, P = 0.055). Clinical appearance (ulcer size/depth, anterior chamber reaction, etc.) did not differ significantly between groups (P ≥ 0.055). Median (range) time to re-epithelialization was longer in MDR vs. non-MDR eyes [29 (10-47) vs. 22 (7-42) days] but the difference was not significant (P = 0.301). Follow-up time was significantly longer in dogs with MDR keratitis [47 (29-590) vs. 29 (13-148) days, P = 0.009]. No other significant differences were noted between MDR and non-MDR eyes in regard to time for ulcer stabilization [4 (1-17) days vs. 4 (1-12), P = 0.699], number of eyes requiring surgical stabilization (7/15 vs. 7/13, P = 0.246) or enucleation (1/15 vs. 2/13, P = 1.000), success in maintaining globe (14/15 vs. 11/13, P = 0.583) or success in maintaining vision (12/15 vs. 10/13, P = 1.000). Conclusions: MDR infections may prolong corneal healing time but did not appear to affect overall clinical outcomes in dogs with bacterial keratitis. Further research is warranted in a larger canine population and other bacterial species.

Culture and characterization of canine and feline corneal epithelial organoids: A new tool for the study and treatment of corneal diseases.

In this study, we isolated and cultured canine and feline 3D corneal organoids. Samples derived from corneal limbal epithelium from one canine and one feline patient were obtained by enucleation after euthanasia. Stem cell isolation and organoid culture were performed by culturing organoids in Matrigel. Organoids were subsequently embedded in paraffin for further characterization. The expression of key corneal epithelial and stromal cell markers in canine and feline organoids was evaluated at the mRNA level by RNA-ISH and at the protein level by immunofluorescence (IF) and immunohistochemistry (IHC), while histochemical analysis was performed on both tissues and organoids using periodic-acid Schiff (PAS), Sirius Red, Gomori's Trichrome, and Colloidal Iron stains. IF showed consistent expression of AQP1 within canine and feline organoids and tissues. P63 was present in canine tissues, canine organoids, and feline tissues, but not in feline organoids. Results from IHC staining further confirmed the primarily epithelial origin of the organoids. Canine and feline 3D corneal organoids can successfully be cultured and maintained and express epithelial and stem cell progenitor markers typical of the cornea. This novel in vitro model can be used in veterinary ophthalmology disease modeling, corneal drug testing, and regenerative medicine.

Kinetics and minimal inhibitory concentrations of ceftiofur in tear film following extended-release parenteral administration (Excede®) in dogs.

Purpose: Describe the pharmacokinetics of extended-release parenteral ceftiofur (Excede®) in canine tear film and compare these concentrations to minimal inhibitory concentrations (MICs) of ceftiofur against common ocular pathogens in dogs. Method: Six dogs of various breeds were enrolled. Disruption of blood-tear barrier was achieved with histamine-induced conjunctivitis to ensure clinical relevance of the results. Each dog received a single subcutaneous injection of 5 mg/kg Excede®, followed by tear collection with Schirmer strips at times 0, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, 72, 96, 120, 144, 168, 192, 216 and 240 h. Drug quantification was performed with liquid chromatography-mass spectrometry. MICs were determined for Staphylococcus pseudintermedius, Streptococcus canis and Pseudomonas aeruginosa by assessing bacterial growth (n = 10 per bacterial species) in the presence of ceftiofur at increasing concentrations. Results: Blood-tear barrier breakdown provided tear film concentrations of ceftiofur 3.2-28.9-fold higher than in the contralateral healthy eye (n = 1 dog, pilot experiment). In all six dogs, ceftiofur concentrations in tears varied from 2.3 to 637.5 ng/mL and were detectable up to 10 days (240 h) after subcutaneous injection. However, tear levels always remained below MICs for common ocular isolates (≥640 ng/mL). Conclusions: Ceftiofur reached the tear compartment (for up to 10 days) after a single parenteral injection, however tear concentrations were extremely variable and too low to be effective against common bacterial pathogens in dogs. Further studies with different ceftiofur dosage or other long-acting injectable antibiotics are warranted.

Effect of topical nitric oxide donors 0.03% nitroglycerin and 0.1% hydralazine on intraocular pressure in healthy canine eyes.

OBJECTIVE: To investigate the potential intraocular pressure (IOP)-lowering effects of nitric oxide (NO)-donating compounds in healthy canine eyes METHODS: A total of 79 dogs were divided into 3 groups in a masked, controlled and randomised study. Group N (n = 26) was administered 0.03% nitroglycerin in one eye and vehicle-control in the other, Group H (n = 26) was administered 0.1% hydralazine in one eye and vehicle-control in the other, while Group C (n = 27) received vehicle-control in both eyes (control group). Following eye drop administration, IOP was measured in both eyes at selected times (10-250 min), along with monitoring of heart rate and signs of ocular discomfort. Data was analysed with repeated measures mixed model and one-way ANOVA RESULTS: IOP was significantly reduced over the 4-h period with 0.03% nitroglycerin (p < 0.0001) but not 0.1% hydralazine (p = 0.520) when compared to contralateral vehicle-controlled eyes. IOP was reduced by up to 12% with 0.03% nitroglycerin from 10 to 70 min post-treatment; however, differences in IOP at individual time points were not statistically significant for either drug (p ≥ 0.133) as compared to contralateral vehicle-control eyes. No treatment group significantly affected heart rate (compared to Group C), and both treatment groups appeared well tolerated CONCLUSIONS: Both compounds were well-tolerated in healthy dogs. Nitroglycerin mildly reduced IOP in canine eyes, and further investigations are warranted in healthy and diseased states (e.g. glaucoma, ocular hypertension).

Variable accuracy, precision, and consistency of compounded famciclovir formulated for management of feline herpesvirus-1 in cats.

OBJECTIVE: To evaluate compounded famciclovir suspensions for accuracy, precision, and consistency in drug content. PROCEDURES: Two compounded famciclovir concentrations were evaluated (250 and 400 mg/mL, 30 preparations total from nine 503A compounding pharmacies) with U.S. Food and Drug Administration (FDA)-approved famciclovir tablets as control. Drug quantification via high-performance liquid chromatography (with famciclovir reference standard and pramipexole internal standard) was performed at 0, 14, and 28 days with concentrations of 90%-110% of labeled dose considered acceptable (US Pharmacopoeia standards). RESULTS: FDA-approved tablets from three different manufacturers were found to be accurate and precise with acceptable drug content. A significantly greater mean deviation from labeled content was noted for 400 mg/mL suspensions (-52.9%) compared to 250 mg/mL suspensions (-18.0%). When assessing time points separately, 15/63 (24%) samples of 250 mg/mL and 0/27 (0%) samples of 400 mg/mL suspensions met the acceptance standards. Coefficients of variation (CV) in drug content among pharmacy batches ranged from 0.5% to 29%, with 5/10 formulations having significantly lower CV% compared to control (decreased precision). Similarly, drug content changed over time (0-28 days) in all compounded formulations, with both downward and upward trends observed (variable consistency). CONCLUSIONS: Most compounded famciclovir formulations were inaccurate, imprecise, and inconsistent. FDA-approved famciclovir tablets may be preferred over compounded famciclovir formulations for the management of feline herpesvirus-1. If compounded famciclovir is used in practice, a concentration of 250 mg/mL is preferred over 400 mg/mL given the lower accuracy of the higher concentration.

Case Report: Successful Management of Refractory Keratomycosis in an Alpaca Using Penetrating Keratoplasty and Combination Antifungal Therapy (Caspofungin 0.5% and Terbinafine 1%).

Fungal keratitis is a common disease in certain parts of the world and affects several species, including equids, camelids, and homo sapiens, leading to blindness or loss of the eye if the infection is not adequately controlled. Reports of clinical use of antifungals caspofungin and terbinafine are limited across both veterinary and human medical literature. The alpaca presented in this case demonstrates that deep keratomycosis can be caused by Scopulariopsis brevicaulis and Fusarium verticillioides, two previously unreported fungi to cause keratomycosis in camelids. This report demonstrates successful management with a combination of surgery and topical ophthalmic treatment with caspofungin 0.5% solution and terbinafine 1% dermatologic cream, after initially failing treatment with topical voriconazole 1% solution. Combination therapy appears more effective than monotherapy with some fungal organisms, and synergy between antifungal agents is thought to play a role in the success of combination therapy. Surgery to remove the bulk of the fungal infection is especially helpful in cases that fail initial medical therapy.

Influence of Schirmer strip wetness on volume absorbed, volume recovered, and total protein content in canine tears.

OBJECTIVE: Determine the protein content and volume of tears sampled by Schirmer strips wetness ranging from 20 to 35 mm. ANIMALS STUDIED: Ten healthy beagle dogs. PROCEDURES: Each dog underwent 20 tear collections per day (10 sessions in each eye, spaced by ≥1 h) for 4 separate days, providing 200 tear samples for each length of wetness evaluated: 20, 25, 30, and 35 mm. A Schirmer strip was placed in each eye until the selected mm-mark was reached, calculating the volume absorbed (VA) as the difference between the post- and pre-collection weight (assuming 1 mg~1 µL for tear fluid), and the volume recovered (VR) as the amount pipetted from the tube following centrifugation. Total protein content (TPC) was measured with infrared spectroscopy. Outcome measures were compared with the Kruskal-Wallis test. RESULTS: Median values for VA (µL), VR (µL) and TPC (mg/mL) were as follows: 20 mm (18, 10, 5.94), 25 mm (22, 12.5, 5.97), 30 mm (25.5, 16, 5.89), and 35 mm (31, 22.5, 7.13). Both VA and VR were significantly greater (p < .001) for Schirmer strips wetness of 35¼30¼25¼20 mm. TPC was significantly greater (p < .001) for 35 > 20-30 mm, but not among other groups (p = 1.000). CONCLUSIONS: The study established normative data to consider when canine studies use Schirmer strips to collect tears for bioanalytical purposes (eg, proteomics, pharmacokinetics). Although 35 mm yielded higher VA and VR, the higher TPC could be explained by greater disruption of ocular surface homeostasis. Absorption to 20-30 mm is the suggested length of strip wetness for bioanalytical tear collection in dogs.

Histologic effects of MicroPulse™ transscleral cyclophotocoagulation in normal equine eyes.

OBJECTIVE: Determine the immediate post-operative effects of MicroPulse™ transscleral cyclophotocoagulation (MP-TSCPC) in healthy equine eyes. ANIMALS STUDIED: Ten adult horses. METHODS: MP-TSCPC was performed on sedated horses in 12 eyes (4 groups) using the following parameters (power, duration, duty cycle): (1) 2000 mW, 180 seconds, 31.3%; (2) 3000 mW, 180 seconds, 31.3%; (3) 3000 mW, 270 seconds, 31.3%; and (4) 3000 mW, 270 seconds, 50%. Three additional eyes were left untreated (control). Eyes were monitored clinically until euthanasia (mean = 3 hours post-procedure). Histologic sections were assessed with light microscopy and transmission electron microscopy (TEM). RESULTS: MP-TSCPC was well tolerated by sedated horses. Adverse effects were only noted in Group 4: ocular hypertension (n = 3/3), conjunctival burns (3/3), aqueous flare (2/3), and a corneal erosion (1/3). Histologic scoring of Group 4 was statistically greater than other treated groups (1-3) and control eyes (P ≤ .021). TEM showed subtle changes to the mitochondria and plasma membrane infoldings of the basilar surface of the nonpigmented epithelium in all treated eyes. CONCLUSIONS: MP-TSCPC does not cause immediate post-procedure adverse clinical effects or pronounced morphological changes to the ciliary body, except with the highest laser settings evaluated (power 3000 mW, duration 270 seconds, duty cycle 50%).

Serum albumin and total protein concentration in the tear film of horses with healthy or diseased eyes.

OBJECTIVE: To determine total protein content (TPC) and serum albumin levels in the tears of horses with healthy or diseased eyes. ANIMALS STUDIED: Forty-two horses with healthy eyes and 11 horses with unilateral (n = 10) or bilateral (n = 1) ocular disease. PROCEDURE: Each eye underwent an ophthalmic examination including detailed conjunctivitis scoring and tear collection with Schirmer strips. TPC and serum albumin levels were quantified in tear samples and compared among healthy eyes, affected eyes, and contralateral unaffected eyes. The impact of the following variables on lacrimal protein levels were assessed: age, breed, and sex (healthy eyes), as well as conjunctivitis score (diseased eyes). RESULTS: Lacrimal TPC ranged from 7.0 to 19.5 mg/mL in healthy eyes, while serum albumin ranged from 71.1 to 711.3 µg/mL (~1.6% of TPC) and was higher in tears of aged and female horses (P ≤ .033). Eyes with ocular disease had significantly greater (P ≤ .001) serum albumin in tears (median 679.6 µg/mL) compared to contralateral unaffected eyes (130.0 µg/mL) and eyes of the reference population (200.7 µg/mL). However, lacrimal TPC did not differ significantly among the 3 groups. Scoring of palpebral conjunctival hyperemia trended toward a positive association with serum albumin in tears (r = 0.49, P = .062). CONCLUSIONS: The protein profile in equine tears differs in health and disease. Serum albumin in tears increases with ocular disease and, similar to other species, might serve as a biomarker for ocular insult in horses. Future studies could investigate the protein levels in horses with specific ocular conditions and help determine the biological importance of albumin on the equine ocular surface.

Prevalence and Antibiotic Susceptibility of Bacterial Isolates From Dogs With Ulcerative Keratitis in Midwestern United States.

The objective of this study was to describe bacterial culture and antibiotic susceptibility results in 476 dogs presenting with suspected bacterial keratitis in Iowa and surrounding Midwestern states, further detailing trends in patient characteristics, seasonality, and antimicrobial resistance. Corneal swabs yielded 465 bacterial isolates and 220 cultures (46.2%) with no apparent growth (0-5 isolates per culture). The most frequent bacterial genera were Staphylococcus (32.3%), Streptococcus (19.1%), and Pseudomonas (12.5%), while the most common bacterial species were Staphylococcus pseudintermedius (26.7%), Streptococcus canis (12%), and Pseudomonas aeruginosa (7.5%). Compared to mixed-breed dogs, canine breeds most likely to be examined for ulcerative keratitis included Boston terrier, Cavalier King Charles spaniel, miniature pinscher, pug, rat terrier, Saint Bernard, shih tzu, and silky terriers. In summer, the likelihood to yield a negative culture was reduced while the likelihood to culture Pseudomonas species was increased. Bacteria considered multidrug resistant (MDR, resistant to ≥ 3 antibiotic classes) represented 20% of all canine isolates and were most prevalent for Staphylococcus species (33%). An alarming, escalating trend of MDR prevalence was noted between 2016 (5%) and 2020 (34%). Individual ophthalmic preparations (i.e., single antibiotics or commercially available antibiotic combinations) with highest efficacy against all bacterial isolates included chloramphenicol (83%), ceftiofur (79%), amikacin (77%), neomycin-polymyxin B-bacitracin (77%), and gentamicin (74%). Efficacy of systemic antibiotics and combinations of ophthalmic preparations was also evaluated. Based on the present findings, triple antibiotic (Neo-Poly-Bac) is recommended as empirical monotherapy for prophylactic antibiotic therapy in dogs with simple corneal ulcers, while a chloramphenicol-ciprofloxacin combination is empirically recommended for therapeutic management of infected corneal ulcers. Pending culture and susceptibility results, appropriate selection of empiric antibiotic therapy is important to enhance therapeutic outcome and reduce antibacterial resistance in dogs with corneal ulceration.

Impact of diurnal variation, sex, tear collection method, and disease state on tear protein levels in dogs.

OBJECTIVE: To investigate the effects of various biological factors on total protein concentration (TPC) and serum albumin levels in canine tears. ANIMALS STUDIED: 10 healthy beagles (5 female, 5 male) were used. PROCEDURES: Experiments were conducted on separate days, collecting tears with either capillary tubes or Schirmer strips, as follows: (i) Tear collection at 3 hours intervals (from 6 am to 12 am); and (ii) Tear collection before and 20 minutes following topical histamine application (1, 10, 375 mg/mL) to induce mild, moderate, and severe conjunctivitis, respectively. TPC and serum albumin were measured with infrared spectroscopy and ELISA, respectively. RESULTS: Tear film TPC and serum albumin ranged from 9.7-26.1 mg/mL and 6.4-1662.6 µg/mL, respectively. Protein levels did not differ significantly among time points (P ≥ .080). Median coefficient of variation (CV%) was lower with Schirmer strips compared to capillary tubes for both TPC (12% vs 15%, P = .020) and serum albumin (57% vs 78%, P = .232). TPC (P < .001), but not serum albumin was greater in male vs. female dogs. Serum albumin, but not TPC (P ≥ .099), increased significantly with each grade of conjunctivitis severity (P < .001), with no differences between collection devices (P ≥ .322); median increase was 106%, 1389%, and 2871% in eyes with mild, moderate, and severe conjunctivitis, respectively. CONCLUSIONS: There is no apparent diurnal variation in canine tear protein levels. Blood-tear barrier breakdown with conjunctivitis allows serum albumin to leak into the tear film at high concentrations. Schirmer strips compare well with capillary tubes for bioanalytical purposes in healthy and diseased eyes, and this collection method may offer improved reproducibility for protein quantification.

Novel use of a combination of extracellular matrices for wound healing following resection of a large inferior eyelid mass in a miniature Hereford.

CASE DESCRIPTION: A 9-month-old miniature Hereford heifer was evaluated for a mass on the right inferior eyelid that had progressed in size over 3 months. CLINICAL FINDINGS: Physical examination revealed a firm, ulcerated, pedunculated mass on the right inferior eyelid that extended from the medial quarter to beyond the lateral canthus of the eye. The base of the mass measured 7.4 × 6.7 cm, and the dorsal margin of the base of the mass was approximately 3 mm ventral to the inferior eyelid margin. Histologic evaluation of incisional biopsy specimens from the mass was consistent with fibrosarcoma. TREATMENT AND OUTCOME: The mass was surgically resected with care taken to preserve the eyelid margin. The resulting 10 × 8.5-cm surgical wound was treated with adjunct CO2 laser therapy and closed by primary closure at its medial and central aspects and placement of a 4.6 × 2.6-cm lyophilized equine amnion multilayer graft and 2 sheets of 4-ply porcine small intestinal submucosa at its lateral aspect. The grafts were kept moist by alternating topical antimicrobial and artificial tear ointments for 3 weeks. The wound healed without complications, resulting in a functional and aesthetically pleasing outcome despite the development of moderate ectropion at the lateral aspect of the inferior eyelid. CLINICAL RELEVANCE: Results suggested that a combination of extracellular matrix scaffolds may be an alternative to extensive skin flaps for management of large dermal wounds, particularly wounds resulting from blepharoplasty where preservation of an eyelid margin is desired.

Impact of acute conjunctivitis on ocular surface homeostasis in dogs.

OBJECTIVE: To investigate the effects of acute conjunctivitis on tear film characteristics and corneal sensitivity in dogs. ANIMALS STUDIED: Eight female spayed Beagle dogs (1.5-2 years old, 7.5-10 kg). PROCEDURES: On two consecutive days, one randomly selected eye in each dog received 1 or 375 mg/mL histamine solution to induce mild or severe conjunctivitis, while the contralateral eye served as control. Diagnostic tests were performed in the following order: fluorescein instillation and repeated tear collection over 20 minutes (to determine tear volume [TV] and turnover rate [TTR] by fluorophotometry), Schirmer tear test-1 (STT-1), tear ferning, corneal esthesiometry, and tear film breakup time (TFBUT). RESULTS: Results are presented as median values for severe conjunctivitis, mild conjunctivitis, and control eyes. Eyes with severe conjunctivitis had significantly higher STT-1 (24, 19.5, 17.5 mm/min; P = .002) and significantly lower TFBUT (10.5, 13.5, 15.5 s; P = .002), but no changes were noted in corneal tactile sensation (2, 2.5, 2.5 cm) or tear ferning (grades 2, 2, 2.5). Severe conjunctivitis significantly increased TV by nearly 10-fold (631, 97, 65 µL) initially (reflex tearing), although basal TV returned rapidly (<5 minutes) in all eyes (46, 58, 48 µL). Finally, there was a nonsignificant trend for higher reflex TTR in the conjunctivitis vs control eyes (68, 58, 43%/min). CONCLUSIONS: Experimentally induced conjunctivitis increases tear quantity and decreases tear quality in dogs, but has no impact on corneal sensitivity. Changes in tear film dynamics could affect ocular pharmacology (eg, precorneal retention time), although homeostasis of lacrimal volume and drainage is rapidly restored.

Comparison of topically administered 0.05% difluprednate and 1% prednisolone acetate for inhibition of aqueocentesis-induced breakdown of the blood-aqueous barrier in healthy dogs.

OBJECTIVE: To compare the efficacy of 0.05% difluprednate ophthalmic emulsion and 1% prednisolone acetate ophthalmic suspension for controlling aqueocentesis-induced breakdown of the blood-aqueous barrier in healthy dogs. ANIMALS: 34 healthy dogs. PROCEDURES: Dogs were allocated to 5 groups (6 to 8 dogs/group) to receive 0.05% difluprednate, 1% prednisolone acetate, or saline (0.9% NaCl) solution (control treatment) in both eyes 2 or 4 times daily. Eye drops were administered topically for 5 consecutive days. Anterior chamber paracentesis (aqueocentesis) was performed in 1 eye on the third day. Automated fluorophotometry was performed immediately before and 20 minutes and 24 and 48 hours after aqueocentesis. Relative fluorescence (RF), defined as fluorescence of the eye that had undergone aqueocentesis divided by fluorescence of the contralateral eye, was calculated to help control for variation among dogs. RESULTS: Mean RF was significantly lower at 24 hours after aqueocentesis in dogs treated twice daily with 0.05% difluprednate or 4 times daily with 1% prednisolone acetate than in dogs receiving the control treatment. At 48 hours after aqueocentesis, mean RF was significantly lower in dogs treated 4 times daily with 1% prednisolone acetate than in control dogs. Mean RF differed over time in dogs treated 4 times daily with 0.05% difluprednate but did not differ over time for any of the other treatments. CONCLUSIONS AND CLINICAL RELEVANCE: All 4 treatments were effective for reducing aqueocentesis-induced anterior uveitis in healthy dogs regardless of the drug or frequency of administration. Topical ophthalmic administration of 0.05% difluprednate may be a viable treatment option for dogs with anterior uveitis and warrants further study.

Bacterial Cross-Contamination in a Veterinary Ophthalmology Setting.

The present study describes the prevalence of bacterial cross-contamination in a veterinary ophthalmology setting, a serious issue that can result in healthcare-associated (or nosocomial) infections among patients and staff. Retrospective (n = 5 patients) and prospective (n = 23 patients) studies evaluated bacterial isolates in companion animals presenting with ulcerative keratitis, sampling the patients' cornea and surrounding examination room, including the environment (exam table, countertop, floor) and ophthalmic equipment (slit lamp, transilluminator, direct ophthalmoscope, indirect headset, tonometer). Results of bacterial culture and antibiotic susceptibility testing were recorded, and degree of genetic relatedness was evaluated in six pairs of isolates (cornea + environment or equipment) using pulse-field gel electrophoresis (PFGE). Overall contamination rate of ophthalmic equipment, environment, and examination rooms (equipment + environment) was 42.9% (15/35 samples), 23.7% (9/38 samples) and 32.9% (24/73 samples), respectively. Methicillin-resistant Staphylococcus pseudintermedius (MRSP), a multi-drug resistant (MDR) pathogen with zoonotic potential, was isolated in 8.2% (6/73) of samples. The patient's cornea was likely the source of cross-contamination in 50% (3/6) of MRSP pairs as evaluated by PFGE; notably, two of the three similar bacterial strains did not have an exact match of their antibiotic susceptibility profiles, highlighting the importance of advanced diagnostics such as PFGE to assess cross-contamination in healthcare facilities. Future work could examine the contamination prevalence of specific equipment or the efficacy of cleaning protocols to mitigate cross-contamination in veterinary practice.