Polidocanol monotherapy for a superficial orbital venous malformation in a horse.

OBJECTIVE: To describe the use of 1% polidocanol as the sole treatment for a superficial orbital venous malformation in a horse. ANIMAL: A 23-year-old Welsh Cobb cross gelding with a distensible swelling affecting the left lower eyelid, and secondary palpebral margin abnormalities and superficial keratitis. PROCEDURE: Color flow Doppler ultrasonography revealed non-pulsatile blood flow within the tortuous vascular network most consistent with a superficial orbital venous malformation appearing to involve the lateral palpebral and transverse facial veins. An intravenous catheter was placed within the lateral aspect of the venous malformation, and agitated saline was slowly injected into the vessel while simultaneously ultrasound imaging the medial aspect in which the bubbles were observed coursing across, consistent with lateral to medial flow. Contrast venography confirmed a corkscrew vessel along the ventral aspect of the orbital rim. Under standing sedation, 1% polidocanol solution was administered slowly through the intravenous catheter while manual pressure was applied on the medial and lateral aspects of the venous malformation. RESULTS: Ultrasonography performed immediately after administration of polidocanol confirmed venous stasis, and formation of a thrombus. No adverse side effects were noted. The venous malformation and associated palpebral margin abnormalities and superficial keratitis resolved at the time of re-examination at 4 months. CONCLUSION AND CLINICAL RELEVANCE: Polidocanol as the sole treatment for a superficial orbital venous malformation in a horse was well tolerated and led to clinical resolution. Sclerosant monotherapy may be a safe treatment option for superficial orbital venous malformations.

Gonioscopic iridocorneal angle morphology and incidence of postoperative ocular hypertension and glaucoma in dogs following cataract surgery.

PURPOSE: To investigate the relationship between gonioscopic iridocorneal angle (ICA) morphology and the incidence of postoperative ocular hypertension (POH) and postoperative glaucoma in dogs undergoing cataract surgery. ANIMALS STUDIED: Retrospective analysis of 138 eyes of 78 canine patients who underwent phacoemulsification at North Carolina State University from December 1, 2015 through April 30, 2017. METHODS: Medical records of all phacoemulsification patients with preoperative RetCam gonioscopic images were reviewed for preoperative, intraoperative, and postoperative variables. Gonioscopic angle indices were calculated using a novel (ZibWest) angle grading system, and these indices were analyzed for outcome-related significance. RESULTS: Increased surgeon experience was associated with increased probability of POH and vision loss. Higher average ZibWest Angle indices (ie, more open angles with less pectinate ligament dysplasia/ abnormality) were associated with a significantly decreased probability of medically unresponsive glaucoma. Increased patient age was significantly associated with an increased probability of both postoperative glaucoma and vision loss. Female dogs were significantly more likely to experience postoperative glaucoma compared to male dogs. Increased surgery time was significantly associated with increased probability of vision loss. CONCLUSIONS: The ZibWest angle index may predict increased risk for developing medically unresponsive glaucoma with cataract surgery. Female sex, and increased patient age, surgical time, and surgeon experience were associated with increased postoperative morbidity.

Glaucoma-associated pain results in mechanical sensitivity changes in dogs: A pilot study.

PURPOSE: To explore the effects of chronic, uncontrolled glaucoma on pressure sensitivity in dogs before and after enucleation of the painful globe. METHODS: Client-owned dogs undergoing enucleation for chronic glaucoma with no other sources of pain were enrolled. Normal dogs of similar breeds and skull morphology were enrolled as controls. Craniofacial ratio (CFR) and relative palpebral fissure width (RPFW) were assessed in all patients. Serial mechanical quantitative sensory testing (QST) was performed the day before surgery, and 14, 30, 60, and 120 days after surgery. QST consisted of electronic Von Frey (eVF), and blunt algometry (BA) performed above and below the nonglaucomatous eye, the metacarpus, and metatarsus. Cochet-Bonnet esthesiometry (CB) was also performed on the remaining eye. RESULTS: Twelve dogs (6 per group) were included. Compared to baseline values, sensitivity tended to decrease over time (increased thresholds) in treatment dogs while it stayed constant or increased slightly in control dogs. The difference in change from baseline sensitivity between control and treatment groups was significant at day 120 using BA at supraorbital (P = .0153), infraorbital (P = .0209), and metacarpal sites (P = .007) and overall (P = .0470). This divergence was also significant using CB (P = .0470) on the opposite cornea. As patient CFR and RPFWV increased, both eVF (P = .005-.023) and BA (P = .004-.041) increased. CONCLUSIONS: Sensitivity to mechanical stimuli decreased both locally and at remote sites in dogs following enucleation for painful chronic glaucoma. Cranial conformation is associated with differences in sensitivity.

Optimizing corneal riboflavin administration in ex vivo horse, dog, rabbit, and pig samples for use in corneal collagen cross-linking.

PURPOSE: Determine optimal iontophoresis times for riboflavin delivery to the corneal stroma across different species and compare these to corneal injection. METHODS: Ex vivo horse, dog, rabbit, and pig globes were treated with riboflavin administered with either iontophoresis for 2.5-20 minutes with or without corneal epithelium; or with purpose-designed precise corneal injection (PCI) application with intact epithelium. Immediately following riboflavin administration, samples were harvested, frozen, and sectioned. Riboflavin penetration was imaged using fluorescence microscopy. RESULTS: Horse samples processed with iontophoresis without epithelium for 2.5, 5, and 7.5 minutes, and processed with intact epithelium for 20 minutes, had mean percent stromal penetration (%SPmean ) of 63.4%, 93.8%, 100.0%, and 0.0% (respectively). Dog samples processed with iontophoresis without epithelium for 2.5 and 5 minutes, had %SPmean of 60.7% and 82.1% (respectively). Pig samples processed with iontophoresis for 5 minutes without and with epithelium had %SPmean of 63.3% and 35.1% (respectively). Rabbit samples processed with iontophoresis without epithelium for 2.5 and 5 minutes, had %SPmean of 81.8% and 100.0% (respectively). For all injected volumes, riboflavin was observed spanning throughout the corneal stroma, and lamellar separation was noted surrounding all sites of injection. CONCLUSIONS: Both iontophoresis and injection via PCI needles provide efficient and effective means of riboflavin administration in ex vivo horse, dog, rabbit, and pig corneas. Epithelial debridement is required for stromal delivery of riboflavin using iontophoresis in horses. Following epithelial removal, riboflavin penetrated through the horse corneal stroma faster than all other species tested.

Suspected Spontaneous Aqueous Humor Misdirection Syndrome in a Boston Terrier.

An eight-year-old female spayed Boston Terrier presented to the North Carolina Veterinary Hospital with glaucoma in the left eye (OS). Initial ophthalmic examination revealed moderate ocular hypertension, a diffusely and markedly shallow anterior chamber with anteriorly displaced iris and lens, vitreal prolapse, and a normal iridocorneal angle (ICA) morphology. The patient displayed a paradoxical response to topical latanoprost with an increase in intraocular pressure. These examination findings led to a putative diagnosis of spontaneous aqueous humor misdirection syndrome (AHMS). The patient was successfully managed with topical carbonic anhydrase inhibitors (CAIs) and apraclonidine for eight months until progressive ulcerative keratitis necessitated enucleation of the affected globe. Histopathology and high-field magnetic resonance imaging (MRI) of the enucleated globe did not identify an underlying cause for the glaucoma. This case suggests that AHMS should be considered in dogs presenting with a shallow anterior chamber, vitreal prolapse, increased intraocular pressure, and no other causes of glaucoma.

A preoperative bupivacaine retrobulbar block offers superior antinociception compared with an intraoperative splash block in dogs undergoing enucleation.

PURPOSE: Investigate nociception differences in dogs undergoing enucleation administered bupivacaine either via preoperative retrobulbar block (pRB) or intraoperative splash block (iSB). METHODS: Prospective, randomized, double-masked, clinical comparison study. Dogs undergoing unilateral enucleation were randomized to two groups: one received bupivacaine pRB and saline iSB of the same volume, and the other received saline pRB and bupivacaine iSB. The following intraoperative parameters were recorded: heart rate (HR), respiratory rate (RR), end-tidal CO2 (EtCO2 ); systolic, mean, and diastolic arterial blood pressure (SAP, MAP, and DAP respectively); inspired end-tidal isoflurane concentration (EtISOIns), and expired end-tidal isoflurane concentration (EtISOExp). Pain scores were recorded pre- and postoperatively. Analgesic rescue was documented. Surgical hemorrhage and postoperative bruising and swelling were graded subjectively by the surgeon (HDW) and study coordinator (AEZ). RESULTS: A significant (P = .0399) increase from baseline in overall mean heart rate was recorded in iSB bupivacaine patients (n = 11) compared with pRB bupivacaine patients (n = 11), with no significant differences in other intraoperative physiologic parameters, or pain scores. More analgesic rescue events occurred in iSB bupivacaine patients compared to pRB bupivacaine patients. A near-significant increase in intraoperative bleeding (P = .0519), and a significant increase in bruising (P = .0382) and swelling (P = .0223) was noted in the iSB bupivacaine group. CONCLUSIONS: Preoperative retrobulbar block bupivacaine is more effective than an iSB bupivacaine at controlling both intraoperative and postoperative nociception in dogs undergoing enucleation. Additionally, iSB causes more postoperative bruising and swelling and may be associated with increased intraoperative hemorrhage.

Retrospective evaluation of canine palpebral masses treated with debulking and cryotherapy: 46 cases.

PURPOSE: To evaluate the recurrence frequency and the time to recurrence of canine palpebral masses treated with debulking and cryotherapy. METHODS: Medical records of dogs that underwent debulking and cryotherapy for palpebral masses from December 2010 to November 2015 at the University of Minnesota's Veterinary Medical Center were reviewed. A telephone survey with owners was used to determine recurrence and time to recurrence. RESULTS: Forty-six masses (31 dogs) were included in this retrospective study. Included palpebral masses were as follows: adenomas 17/46 (37%), epitheliomas 8/46 (17.4%), papillomas 6/46 (13%), inflammatory masses 6/46 (13%), mixed adenoma-papillomas 6/46 (13%), mixed epithelioma-papillomas 2/46 (4.4%), and a melanocytoma 1/46 (2.2%). Of the seven masses that were noted to recur (7/46, 15.2%), three were mixed adenoma-papillomas (three of six adenoma-papillomas, 50%), two were epitheliomas (two of eight epitheliomas, 25%), one was a papilloma (one of six papillomas, 16.7%), and one was a melanocytoma (one of one melanocytoma, 100%). Average recurrence time was 367.9 days [range: 30-904 days]. A significant association between tumor type and tumor recurrence was found (P = .009). Adenomas were significantly less likely to recur (P = .017), and mixed adenoma-papillomas were significantly more likely to recur (P = .001). CONCLUSIONS: Debulking and cryotherapy is an effective method of treatment for eyelid masses in dogs with a low study recurrence rate of 15.2% and average recurrence time of 367.9 days. Results also suggest that mixed adenoma-papilloma masses have a significantly higher recurrence rate than other eyelid masses, whereas adenomas had no recurrence in our study population.

Objective evaluation of the systemic effects of topical application of 1% atropine sulfate ophthalmic solution in healthy horses.

OBJECTIVE To determine the safety of topical administration of 1% atropine ophthalmic solution in healthy horses by objectively measuring gastrointestinal transit time. DESIGN Randomized, masked, controlled crossover study. ANIMALS 6 adult geldings. PROCEDURES Horses were randomly assigned (3/group) to first receive topical treatment of the left eye with 1% atropine or artificial tears solution; the right eye was left untreated. After 24 hours of treatment every 6 hours, 200 nontoxic beads were administered to each horse via nasogastric intubation and treatment frequency was decreased to every 12 hours for 4 more days. Pupillary light reflexes (PLRs), mydriasis, heart rate, fecal bead passage, abdominal girth measurements, auscultable gut sounds, fecal weight, and clinical signs of abdominal pain were monitored. Following a 4-week washout period, horses received the opposite treatment in the left eye and measurements were repeated. Serum atropine concentration (reflecting systemic absorption) was measured with an ELISA at various points after initial atropine administration. RESULTS No horse had subjective or objective evidence of colic or ileus at any monitoring point. Complete mydriasis of the left eye with absence of the PLR was identified in 5 horses within 6 hours and in all 6 horses within 12 hours after initial atropine administration. One horse had mydriasis with an absent PLR in the untreated eye by day 5 of atropine treatment. At no point was atropine detected in serum samples of any horse. CONCLUSIONS AND CLINICAL RELEVANCE Topical atropine application at clinically appropriate doses induced no evidence of ileus in healthy horses.