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OBJECTIVE To compare electroretinographic (ERG) responses obtained in dogs before and after oral administration of gabapentin, trazodone, and a combination of both medications. ANIMALS 12 clinically normal dogs. PROCEDURES A short-protocol ERG with 20 minutes of dark adaption was recorded for all dogs to establish baseline ERG responses. Dogs then received gabapentin (approx 30 mg/kg), trazadone (approx 20 mg/kg or approx 5 mg/kg), or a combination of gabapentin (approx 20 mg/kg) and trazodone (approx 5 mg/kg) orally, and the same ERG protocol was repeated 2 hours later. Dogs were given a washout period of at least 1 week between treatments. RESULTS a-Wave amplitudes were significantly (P = 0.018) decreased after administration of the combination of gabapentin and trazodone. b-Wave amplitudes were significantly decreased after administration of the 20-mg/kg dose of trazodone (P = 0.006) and after administration of the combination of gabapentin and trazodone (P = 0.002). Heavier dogs that received higher total doses of trazodone had decreases in a-wave amplitude after administration of the 20-mg/kg dose of trazodone and in b-wave amplitude after administration of the 5-mg/kg dose of trazodone. CLINICAL RELEVANCE High doses of trazodone and the combination of gabapentin and trazodone significantly decreased a-wave and b-wave amplitudes in clinically normal dogs. However, the effects on retinal responses had little clinical importance. Therefore, these medications can be used safely in a clinical setting; however, further studies are needed in dogs with retinal disease.

Aged cotton rats (Sigmodon hispidus) from an established breeding colony displayed signs of spontaneous exophthalmos. Of a total of 118 colony animals that were older than 6 mo of age, 37 (31%) displayed signs of exophthalmos. These rats were clinically healthy and had no other signs of disease. Ophthalmic exams, molecular and microbiologic testing, and histopa- thology were performed to determine the cause of the exophthalmos and to provide appropriate treatment. Environmental monitoring records were also reviewed for vivarium rooms in which the cotton rats were housed. Histopathology findings supported that the exophthalmos in these cotton rats was secondary to retro-orbital thrombosis associated with cardiomyopathy. The exophthalmic eyes were treated by either removal of the affected eye (enucleation) or surgical closure of the eyelids (temporary tarsorraphy). Enucleation of the exophthalmic eye was the best intervention for these aged cotton rats. These findings demonstrate the potential for a high incidence of ocular problems occurring secondary to cardiomyopathy in aged cotton rats. Enucleation as a therapeutic intervention for exophthalmic eyes in aged cotton rats prolongs the morbidity-free time span during which these aged animals can be used experimentally.

PURPOSE To compare cataract characteristics and complications related to cataracts and phacoemulsification in the Siberian Husky (Huskies) versus other canine breeds (non-Huskies). ANIMALS A total of 50 Huskies (92 eyes) and 96 non-Huskies (182 eyes) were evaluated. METHODS Medical records of Huskies (at four university veterinary hospitals, 2008-2018) and non-Huskies (Colorado State University, 2017-2018) diagnosed with cataracts were reviewed. Age of dog, cataract stage at presentation, and pre- and post-operative complications were recorded and analyzed. RESULTS Mean (±standard deviation) age at presentation was significantly lower in Huskies (3.5 ± 3.3 years) compared to non-Huskies (9.5 ± 2.9 years) (p

OBJECTIVE To compare intraocular pressure readings from three different tonometers, the Tono-Pen AVIA® (TP), TonoVet® (TV) and TonoVet Plus® (TV+) and to determine how measurements from each tonometer are affected by central corneal thickness (CCT). ANIMALS Ninety dogs. PROCEDURES Normal dogs and dogs with ocular disease were selected for study inclusion. Central corneal thickness measurements were gathered with the Pachette 4 ultrasonic pachymeter, and IOP measurements were gathered with the three tonometers in random order. ANOVA or Wilcoxon tests were utilized for overall group comparisons. Linear regression analyses were utilized to determine the association between IOP and CCT. RESULTS When comparing tonometers to each other, for all dogs, readings from the TV+were significantly different compared to the TV (p =

OBJECTIVES To identify the minimum inhibitory concentration (MIC) distribution for commonly used topical antibiotics from isolates of dogs and horses with ulcerative bacterial keratitis, and to investigate changes in MIC values over time and following treatment with topical fluoroquinolones. ANIMALS STUDIED One hundred thirty-four client-owned dogs and 20 client-owned horses with bacterial ulcerative keratitis. PROCEDURE Minimum inhibitory concentration values for 14 topical antibiotics were reported for canine and equine cases of bacterial ulcerative keratitis between 2013 and 2018. Changes in MIC values over time and after treatment with topical fluoroquinolones were reported. RESULTS The three most common bacterial genera isolated were Staphylococcus, Streptococcus, and Pseudomonas. Together, these represented 79.4% of canine cases and 77.4% of equine cases. Overall, isolates from horses tended to have lower MIC values, as did Pseudomonas isolates from both dogs and horses, compared to other bacterial genera, especially Staphylococcus spp. The MIC values of erythromycin and trimethoprim sulfa for Staphylococcus spp., and the MIC value of moxifloxacin for Pseudomonas significantly increased over time. Previous topical fluoroquinolone use was associated with a significant increase in the MIC value of ofloxacin in canine and equine Staphylococcus isolates and current topical fluoroquinolone use was associated with significant increases in the MIC values of ciprofloxacin, moxifloxacin, and ofloxacin in canine Staphylococcus isolates. CONCLUSION Patients previously or currently treated with topical fluoroquinolones, particularly in Staphylococcus infections, may require alternative antibiotics or additional antibiotic classes other than fluoroquinolones. Bacterial culture with MIC susceptibility testing should be highly recommended when a Staphylococcal infection is suspected.

OBJECTIVE To determine the effects of grape seed extract (GSE), lutein, and fish oil containing omega-3 fatty acids on oxidative stress, migration, proliferation, and viability of lens epithelial cells (LECs). SAMPLE Lens capsules or cultured LECs obtained from canine cadavers. PROCEDURES An antioxidant reductive capacity assay was used to determine reducing capability of each substance. The LECs were cultured and incubated with various substances, including N-acetyl cysteine (NAC), when appropriate, and dimethyl sulfoxide (DMSO) as positive and vehicle control substances, respectively. A dichlorofluorescein assay was used to evaluate reactive oxygen species (ROS) production, and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine cell viability. Ex vivo posterior capsule opacification (PCO) was used to evaluate LEC migration and proliferation. RESULTS Antioxidant reductive effects of GSE surpassed those of NAC, lutein, and fish oil containing omega-3 fatty acids. The GSE reduced ROS production in LECs, compared with the DMSO vehicle control, whereas lutein was pro-oxidative. All test substances reduced cell viability. Ex vivo PCO was not altered by GSE, was decreased by lutein, and was increased by fish oil containing omega-3 fatty acids, compared with results for the DMSO vehicle control. CONCLUSIONS AND CLINICAL RELEVANCE Only GSE had significant antioxidant capabilities and reduced ROS production; however, no effect on ex vivo PCO was detected. Fish oil containing omega-3 fatty acids increased ex vivo PCO. No conclusions could be made regarding antioxidant effects of these substances on LECs. These findings suggested that the substances will not decrease PCO.

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.

The cornea plays an important role in transmitting light and providing protection to the eye, but is susceptible to injury and infection. Standard treatments for corneal wounds include topical lubricants, antibiotics, bandage contact lens, and surgery. However, these measures are often ineffective. Here we show that MG53, a protein with an essential role in cell membrane repair, contributes to the corneal injury-repair process. Native MG53 is present in the corneal epithelia, tear film, and aqueous humor, suggesting its potential function in corneal homeostasis. Knockout of MG53 in mice causes impaired healing and regenerative capacity following injury. Exogenous recombinant human MG53 (rhMG53) protein protects the corneal epithelia against mechanical injury and enhances healing by promoting migration of corneal fibroblasts. Using in vivo alkaline-induced injury to the rat cornea, we show that rhMG53 promotes re-epithelialization and reduces post-injury fibrosis and vascularization. Finally, we show that rhMG53 modulates TGF-β-mediated fibrotic remodeling associated with corneal injury. Overall, our data support the bi-functional role of MG53 in facilitating corneal healing and maintaining corneal transparency by reducing fibrosis and vascularization associated with corneal injuries., Heather Chandler, Tao Tan, Chunlin Yang et al. find that the cell membrane repair protein MG53 plays a key role in repairing cornea injury. Using mouse and rat models, they show that recombinant human MG53 protects the cornea against injury and enhances healing.

Purpose To determine whether trypan blue (TB) reduces canine lens epithelial cell (LEC) or corneal endothelial cell (CEC) viability in vitro; if cell death is noted, to subsequently evaluate the molecular mechanism. Methods Cellular viability was determined using a lactate dehydrogenase (LDH) assay. In TB-treated LECs, caspase 3/7 activity was assessed to evaluate apoptosis; autophagy was evaluated using immunoblotting against LC3 and p62. To evaluate the effects of TB on ex vivo posterior capsule opacification (PCO), following mock cataract surgery, lens capsules were treated with TB and subsequently maintained in culture to determine LEC migration and proliferation. Results Following acute exposure, TB did not significantly reduce LEC or CEC viability at any of the concentrations tested. Increased caspase 3/7 activity was found in LEC cultures treated with TB for an extended period of time; no change in LC3 or p62 expression was noted. Ex vivo PCO formation was not significantly altered by TB treatment. Conclusions Acute exposure to TB did not reduce LEC or CEC viability, and only longer exposure to TB was able to initiate apoptosis. Treatment with intraocular TB at the time of cataract surgery is likely safe to the CECs but will not prevent PCO formation.

Objective To determine whether any association exists between the onset of feline acute bullous keratopathy (ABK) and administration of systemic corticosteroid or immunosuppressive therapy. Animals studied Medical records of cats diagnosed with ABK between the years of 2000 and 2008 were retrospectively reviewed. Breed, age at diagnosis, weight, systemic disease status, eye affected, ophthalmic examination findings, systemic and topical therapy instituted, dosage and duration of therapy, visual outcome and histopathological analyses were recorded in cases meeting the inclusion criteria. Results A total of 12 cats of a surveyed population of 70 167 met the inclusion criteria with 17/24 eyes affected by ABK. Medical and/or surgical therapy was utilized for management of ABK with 13/17 eyes remaining sighted at the time of last follow-up. In a subset of cases corneal cytology, aerobic bacterial culture, FHV-1 PCR, virus isolation and/or histopathology were performed; no infectious organisms were identified. A rupture in Descemet's membrane of the cornea was identified histologically in two globes. A total of 10 of 12 cats had been previously diagnosed with ongoing systemic disease. A total of 10 of 12 cats were receiving systemic therapy, and a significant association (P < 0.001) was noted between systemic administration of corticosteroids and/or cyclosporine A and the development of ABK. A total of 8 of 10 cats were administered oral prednisolone at doses between 1–2 mg/kg every 12–24 h. A total of 5 of 8 cats receiving oral prednisolone were concurrently administered oral cyclosporine at doses of 1.5–7 mg/kg every 12–24 h. Systemic cyclosporine therapy was found to be a significant risk factor (P < 0.001) for ABK development, while systemic prednisolone was not significant (P = 0.10). Conclusions Systemic cyclosporine administration appears to be a risk factor for development of ABK in the population of cats studied.

To evaluate the prevalence of keratoconjunctivitis sicca (KCS) in diabetic and nondiabetic dogs following phacoemulsification.Medical records were reviewed for signalment, body weight, diabetes status, and STT at the preoperative and all postoperative examinations. A clinical diagnosis of KCS was defined as a STT15 mm/min with compatible clinical signs. Schirmer tear test values and the prevalence of KCS based on STT15 mm/min were evaluated at 2-4, 5-8, 9-14, 15-20, and 41-52 weeks postoperatively. Size of dog (large,10 kg; small, ≤10 kg) and STT ranges (15 mm/min, 15-22 mm/min and22 mm/min) were categorized for analysis of effect of body weight and STT on prevalence of KCS.One hundred and seventeen nondiabetic (198 eyes) and 118 diabetic dogs (228 eyes) were evaluated. KCS was diagnosed in nearly twice as many diabetics as nondiabetics (27.4% vs. 15.4%) within 2 weeks postoperatively (P = 0.0088). Percentage of eyes with KCS among all dogs decreased over time and did not differ significantly after the first postoperative visit. Diabetic small dogs were 1.7 times more likely to have KCS than nondiabetic small dogs (P = 0.0052). Preoperative STT was significantly associated with likelihood of postoperative KCS among large (P0.0001), but not small dogs (P = 0.0781). Among large dogs, eyes with STTs between 15 and 22 mm/min were approximately 3 times more likely to be diagnosed with KCS after surgery than those with STT22 mm/min.The greatest risk for KCS for all dogs is during the first 2 weeks postoperatively. Populations at greatest risk for postoperative KCS are small dogs, small diabetic dogs, and large dogs with preoperative STT ≤22.

Objective To evaluate and compare surgical outcome and complications in canine eyes with stable, cataractous lenses undergoing routine phacoemulsification and intraocular lens (IOL) implantation with or without implantation of a capsular tension ring device (CTR). Procedures Dogs undergoing routine bilateral phacoemulsification and IOL implantation had one eye randomly chosen to have a CTR (47 eyes) inserted while the contralateral eye served as a control (47 eyes). The CTR was placed in the capsular bag following phacoemulsification and immediately prior to IOL implantation. All eyes received acrylic foldable IOLs. Patients were evaluated intra- and postoperatively, and complications were compared between eyes with and without a CTR. Results There were no intra-operative complications associated with implantation of the CTR. Postoperatively, the overall incidences of glaucoma (6%), intraocular hemorrhage (4%), and retinal detachment (2%) were equal between control and CTR eyes at the time of last follow-up. There was no significant difference in overall incidence of immediate postoperative uveitis (35% vs. 38%) or fibrin (19% vs. 15%) between control and CTR eyes. Follow-up time ranged from 2 weeks to 21 months. Conclusion In canine eyes with stable cataractous lenses undergoing routine phacoemulsification and IOL implantation placement of a CTR does not increase the risk of intra- or postoperative complications.

Purpose To determine appropriate location and energy settings for trans-scleral cyclophotocoagulation (TSCPC) for buphthalmic equine globes. Animals Eleven horses with a buphthalmic eye blinded by glaucoma presented for enucleation. Methods Globe and corneal dimensions were measured via ultrasonography and calipers, and TSCPC was performed under general anesthesia immediately prior to enucleation. Part 1: In nine globes, sixty sites were lasered 4 mm posterior to the limbus in the dorsotemporal and ventrotemporal quadrants at settings of 1500 milliwatts and 1500 ms. Globes were processed and sectioned sagitally over the temporal aspect in two blocks, each with five histologic sections examined by light microscopy. A digital imaging system was used to determine the location and length of the pars plicata on one slide from each block. Part 2: Based on results in Part 1, two globes were measured and lasered using the same time and energy settings at the following distances posterior to the limbus: 8 mm dorsally, 6 mm dorsotemporally, 5 mm ventrotemporally, and 5 mm ventrally. Results Globe and corneal dimensions exceeded normal values in all globes. Part 1: In all nine globes, photocoagulation affected the anterior ciliary processes and iris base and in 8/9 coagulation of the pectinate ligaments was noted. Part 2: In both globes, coagulation was confined to the pars plicata. Conclusions The previously recommended TSCPC sites are located too far anteriorly for a buphthalmic globe. Buphthalmic equine globes should have TSCPC performed at the following distances posterior to the limbus: 6–8 mm dorsally, 5–6 mm dorsotemporally, 4–5 mm ventrotemporally, and 4–5 mm ventrally.

Objective To describe the clinical presentation, treatment, and outcome of a corneal dystrophy in Friesian horses and to analyze affected horses' pedigrees to investigate its heritability. Animals Nine Friesians with bilateral disease were identified. Procedure Retrospective medical record review was used to identify Friesian horses exhibiting bilateral symmetric corneal lesions. Variables identified from medical records included patient sex and age at diagnosis; location, depth and size of corneal lesions; medical and surgical therapy instituted; and visual outcome. A four-generation pedigree for each included horse was used to construct a combined pedigree. Results The nine included horses had an average age at diagnosis of the first eye of 10.7 years, with males (8/9) significantly more frequently affected than females (1/9), P = 0.012. Lesions were inferior and averaged 5 mm in diameter. Depth ranged from superficial facets to perforations, which developed in nine of 18 eyes. Eight of nine perforations were surgically repaired, with seven of eight repaired eyes visual at last follow-up. All nine eyes that had not perforated remained visual. All affected horses shared a common ancestor within six generations. Conclusions This form of corneal dystrophy in Friesian horses, characterized by bilateral symmetric stromal loss, appears to be progressive but responds well to surgical repair, occurs more frequently in males, may have a genetic component in Friesian horses, and may be a variant of pellucid marginal degeneration.

Objective To evaluate the success rate and outcome of trans-corneal reduction of anterior lens luxation (TR-ALL) in dogs with lens instability. Animals Studied Nineteen dogs with anterior lens luxation. Procedures Medical records of dogs with anterior lens luxation (ALL) were reviewed: dogs were included if TR-ALL was performed followed by medical therapy in the form of topical 0.005% latanoprost ophthalmic solution. The duration of ALL, vision status, ophthalmic examination abnormalities, reason for performing TR-ALL and details of TR-ALL were recorded. Success rate for TR-ALL as well as postprocedure complications were also assessed. Results Twenty eyes from 19 dogs met the inclusion criteria. Median age was 6.5 years (0.3–15 years) and 47% were terriers (9/19). Successful TR-ALL was achieved in 85% of eyes (17/20); failure was attributed to posterior synechia or vitreous expansion. Short-term complications included corneal ulceration (2/20) and anterior uveitis (3/20); recurrence of anterior luxation occurred in only one dog. Median follow-up for visual eyes (11) following successful TR-ALL was 353 days (range of 1 to 1182 days). Vision was retained in 54.5% (6/11) of eyes with a median time to vision loss of 12 months as a result of glaucoma or presumed retinal detachment. Conclusions Trans-corneal reduction of ALL provides a non-surgical alternative to intracapsular lens extraction (visual eyes) or enucleation (nonvisual eyes) in dogs. Long-term visual outcome of TR-ALL is comparable to intracapsular lens extraction for ALL.

Objective To describe the long-term histologic and intraocular pressure (IOP) lowering effects of diode laser transscleral cyclophotocoagulation (TSCP) on the normal equine eye. Animals Eight normal adult horses. Procedures TSCP was performed in one randomly assigned eye. Sixty spots were treated at settings of 1500 ms and 1500 mW. Two horses were randomly selected for euthanasia at 2, 4, 12, or 24 weeks post-TSCP. Both eyes were enucleated and histologically evaluated. Intraocular pressure was measured by applanation tonometry prior to TSCP, immediately post-TSCP, twice daily for 7 days post-TSCP and then monthly until study conclusion. A longitudinal model estimated the average IOP values for the treated and untreated eyes at 1 week, 1, 3, and 6 months post-TSCP. Results All treated eyes at all time periods exhibited four characteristic histologic lesions: scleral collagen hyalinization, ciliary body pigment dispersion and clumping, focal disruption of the ciliary body epithelium, and focal ciliary process atrophy. After TSCP, there were no significant changes in IOP from baseline for the control eyes, while the IOP in treated eyes was significantly decreased from baseline (P

Summary Glaucoma is a serious complication of anterior uveitis that can result in significant ocular discomfort and loss of vision. As glaucoma is insidious and mostly asymptomatic until late in the course of disease, it is often undiagnosed. Equine recurrent uveitis is the most common underlying disorder: it is a disease of high prevalence, characterised by recurrent-remitting episodes of ocular inflammation. Here, the inflammatory cells and mediators they release alter the normal anatomic structure of the anterior chamber and aqueous drainage pathways of the eye. These changes alter the homeostatic mechanisms of intraocular pressure control. Management of glaucoma secondary to uveitis can be challenging due to the difficulties of managing the underlying disorder and its effects on the eye. This article reviews the pathogenesis of uveitic glaucoma in the horse and medical and surgical management options.

Objective To evaluate the outcome of diode laser transscleral cyclophotocoagulation (TSCP) for the treatment of glaucoma in horses. Procedure Medical records at The Ohio State University were reviewed. All horses that underwent diode laser TSCP between the years of 1995 and 2007 were included. Preoperative, procedural and clinical follow-up data were collected, and telephone follow-up was performed. Results Forty-two eyes of 36 horses were included. Twenty-four hours prior to surgery mean intraocular pressure (IOP) was 37.17 ± 13.48 mmHg (42 eyes). Forty-one of 42 eyes (98%) were sighted and 39 of 39 (100%) of eyes were receiving topical glaucoma medication. At 3–5 weeks postoperatively the average IOP was 19.36 ± 12.04 mmHg (22 eyes). IOP remained significantly lower than pretreatment values at all periods of clinical follow-up (P

At The Ohio State University from 1994-2006 six of seven horses evaluated for primary orbital disease were diagnosed with extra-adrenal paraganglioma (EAPG). The horses ranged in age from 14 to 24 years, with a mean of 16.8 years. Duration of clinical signs was 1.5 years to 5 years, with a mean of 2.8 years. Clinical signs varied, but all six had non-painful exophthalmus of the right eye. Five horses had complete ocular exams reported; three of five had decreased to absent vision, two of five had pale optic nerves, and in three of five, difficulty of retropulsion of the globe was noted. Diagnostic tests performed included complete blood count, serum profile, radiography, ultrasound, computed tomography, true-cut biopsy, ocular examination, guttural pouch endoscopy, oral examination, and physical examination. Expulsive hemorrhage during orbital exenteration occurred in all horses. In five of six cases, tumor extension through the orbital foramen was apparent intra-operatively. Histopathologic appearance of all surgically removed tissues consisted of sheets of polygonal cells with abundant lightly granular cytoplasm, round nuclei with vesicular chromatin, and rare mitoses. Neoplastic cells were arranged into small groups separated by a fine fibrovascular stroma. All six cases were chromagranin positive on immunohistochemical staining. Follow-up ranged from six months to six years, with a mean of two years. Four of the five horses that recovered from surgery had no apparent tumor recurrence in 6-48 months.

Case Description—A 13-year-old female Miniature Horse was evaluated for progressive unilateral exophthalmia of the left globe of 3 weeks' duration. Clinical Findings—Results of a physical examination were unremarkable. Ophthalmic examination identified exophthalmus of the left globe with complete resistance to retropulsion and mild blepharoconjunctivitis. Computed tomography revealed a large, space-occupying mass within the left caudal maxillary and left conchofrontal sinuses. The mass extended into the left retrobulbar space and contacted the cribriform plate. Trephination yielded copious amounts of turbid yellow fluid. The diagnosis was a sinonasal cyst. Treatment and Outcome—Subtotal surgical excision of the cyst via a frontonasal osteoplastic flap was curative, with complete resolution of the exophthalmus. Histologic examination confirmed diagnosis of a sinonasal cyst. There was no evidence of cyst recurrence by 4 months after surgery. Clinical Relevance—Sinonasal cyst should be a differential diagnosis for retrobulbar disease in horses. Exophthalmia may be the only clinical finding in horses with a sinonasal cyst.

The goals of canine cataract and lens instability surgery should be to ensure a small incision, minimal tissue trauma, shortened surgical time, maintenance of the anterior chamber, and restoration of emmetropia through the use of a stable intraocular lens specifically designed for the canine eye. While this is usually the case with routine phacoemulsification and in-the-bag intraocular lens implantation, it is often not the case with lens instability, lens luxation or large posterior capsular ruptures. In such cases the incisions are often larger, surgical time and tissue trauma are excessive, and the patient is often left aphakic. The goal of this paper is to present a modified ab externo technique designed to allow removal of the lens and placement of a ciliary sulcus sutured IOL through a small incision, with minimal trauma and shortened surgical time. Use of this technique may allow more canine patients to be emmetropic postoperatively. In addition, the ease of this procedure may encourage earlier removal of an unstable lens and decrease the risk of secondary glaucoma and retinal detachment that occur in association with lens luxation.

Objective To identify visual outcome and postoperative complications following phacoemulsification of equine cataracts. Animals Records of 39 horses (55 eyes) with cataracts were reviewed. Methods Eyes with cataracts removed by phacoemulsification were included in the study. Data collected included age, breed, sex, stage and etiology of cataract, unilateral vs. bilateral involvement, and ultrasound findings. Horses were grouped by etiology of the cataract. Visual outcome and complications were evaluated for each group and the overall population. Results Immediately postoperatively 46 out of 47 eyes (98%) were sighted. Four weeks postoperatively 23 of 29 operated eyes (79%) were sighted [13/18 (72%) eyes with congenital/juvenile onset, 6/6 (100%) eyes with traumatic and 4/5 (90%) eyes with uveitis-induced cataracts], with 18 eyes lost to follow-up. The most common postoperative complications included corneal edema (19 eyes/40%), fibrin in the anterior chamber (11 eyes/23%), postoperative ocular hypertension (9 eyes/19%), synechia/dyscoria (9 eyes/19%), and hyphema (7 eyes/15%). Conclusions Prognosis for vision is favorable for horses following phacoemulsification and planned posterior continuous tear circular capsulorrhexis. Success rates depend on age of patient, cause of cataract and pre-existing intraocular disease. The highest success rate occurred in eyes with traumatic cataracts.

Objective To describe the clinical presentation and surgical outcome of diabetic canine patients with cataracts and preoperative spontaneous lens capsule rupture. Animals studied A total of 20 dogs and 40 eyes were included in the retrospective evaluation. The patients’ ages ranged from 5 to 14 years (mean 8.5 years). Results All dogs had clinical diabetes mellitus, with the duration since diagnosis ranging from 30 to 240 days (mean 123 days). Cataracts were bilateral and noted to have been present for 14–112 days (mean 39 days). Of the 40 eyes affected with cataracts, 30 had a spontaneous rupture of the lens capsule prior to surgery. The capsular rupture was diagnosed on clinical examination in 28/30 eyes and was noted intraoperatively in 2/30. The location of the capsular rupture was equatorial in 29/30 and posterior in 1/30 eyes. Surgery was performed in 38/40 eyes, with one case lost to follow-up without surgical intervention. Prior to surgery, routine diagnostic ophthalmic examination, ocular ultrasound, electroretinography, and systemic evaluation were performed in all dogs. Surgical procedures included phacoemulsification in 28/40 eyes, with IOL placement performed in 20/28 eyes. Intrascleral prosthesis placement or enucleation was performed in 8/40 and 2/40 eyes, respectively, due to a significantly reduced ERG or secondary glaucoma. Conclusions The duration of clinical follow-up (19/20 dogs) ranged from 1 to 36 months (mean 12.9 months). All eyes that had cataract surgery with or without IOL placement were sighted at the time of the last follow-up examination. Spontaneous lens capsule rupture associated with diabetes mellitus, cataract and rapid lens intumescence occurs in the dog. Early surgical intervention, prior to secondary complications of glaucoma and loss of retinal function, is associated with a favorable outcome.

Objective—To determine effects of topical antimicrobial and antimicrobial-corticosteroid preparations on the ocular flora of horses. Animals—40 horses. Procedure—One eye was treated 3 times daily for 2 weeks with one of the following ointments: 1) neomycinbacitracin- polymyxin B, 2) 0.6% prednisolone-0.3% gentamicin, 3) neomycin-polymyxin B-0.05% dexamethasone, or 4) treated (artificial tears) control. Contralateral eyes of treated control eyes served as untreated control eyes. Corneal and conjunctival specimens for bacterial and fungal cultures were collected prior to initiation of treatment, after 1 and 2 weeks of treatment, and 2 weeks after concluding treatment. Changes in culture growth quantity scores of bacterial and fungal species were analyzed. Results—The most common species before treatment were the following: gram-positive bacteria included Streptomyces spp (66%) , Staphylococcus spp (46%) , Bacillus spp (32%) , and Streptococcus spp (32%); gramnegative bacteria included Moraxella spp (28%) , Escherichia coli (24%) , Acinetobacter spp (18%), and Enterobacter spp (14%); and fungi included Aspergillus nidulans (56%) , Cladosporium spp (32%), and Aspergillus fumigatus (22%). In all groups, the percentage of positive bacterial culture results, growth quantity score of gram-positive bacteria, and number of bacterial species isolated decreased at week 1 and increased at week 2, whereas growth quantity score of gram-negative bacteria decreased throughout treatment. Differences were not significant among groups. Fungal growth quantity score decreased during treatment in all groups. Repopulation of bacterial and fungal species occurred. Conclusions and Clinical Relevance—All interventions decreased the number of microorganisms. Repopulation of normal flora occurred during and after treatment. (Am J Vet Res 2005;66:800–811)

The objective of this study was to describe the clinical, histologic and immunohistochemical features, the surgical treatment, and outcome of a cataract secondary to persistent hyperplastic tunica vasculosa lentis/persistent hyperplastic primary vitreous (PHTVL/PHPV) in a dog. A 4-month-old male Bloodhound dog presented for evaluation of a cataract. A complete ophthalmic examination and ocular ultrasonography were performed. A resorbing cataract with intralenticular hemorrhage, lens induced uveitis, and PHTVL/PHPV were diagnosed. Extracapsular cataract extraction using phacoemulsification was performed. A primary posterior capsulectomy was performed to remove a retrolental plaque with the posterior capsule; the excised plaque was submitted for histopathology and immunohistochemical staining. A 41-Diopter intraocular lens (IOL) was implanted. Functional vision was maintained postoperatively during the 21-month follow-up period. Histologically, the posterior capsule was coiled and exhibited duplication. The retrolental plaque was comprised of dense fibrous connective tissue, blood vessels, free red blood cells, hemosiderin-laden macrophages, a pocket of neural tissue and numerous perivascular mast cells. With immunohistochemical staining, the neural elements were determined to be glial cells compatible with astrocytes. Cataract secondary to PHTVL/PHPV can be successfully treated using phacoemulsification and planned posterior capsulectomy. Posterior lens capsule duplication, mast cells and astrocytic glial cells may be normal components of the fibrovascular retrolental plaque associated with PHTVL/PHPV.

No single viscoelastic material has all the properties required for every surgical procedure. Ophthalmic surgeons should be familiar with the advantages and disadvantages of several viscoelastics and realize the limitations encountered if the surgeon chooses to rely on a single viscoelastic. It is possible in the future that newer viscoelastics may become available offering aspects of cohesive and dispersive properties that make them easy to remove and not associated with postoperative hypertension. Investigation into other types of viscoelastic materials, such as poly-acrylamide (Orcolon) [33,51,52], human collagen [33,53], polytriethylene-glycol monomethacrylate, and polyglycerol monomethacrylate [48], may result in the availability of synthetic viscoelastic materials. Rethinking how we use viscoelastics may also be indicated. The approach of a single or repeat instillation of a viscoelastic only to have it aspirated during the procedure could be modified by using a continuous infusion ofa dilute viscoelastic [54]. One study diluted hyaluronic acid to a concentration of 0.06% to 0.12% and maintained continuous infusion of the viscofluid through the PE irrigation line [54]. It has been suggested that this may reduce turbulence and improve tissue protection [54].

Background The aim of the study was to evaluate ex vivo the effects of using a custom tip to direct a pulsed stream of fluid to remove residual lens epithelial cells (LECs) and reduce posterior capsule opacification (PCO) formation following phacoemulsification. Methods Twenty-four canine cadaver eyes were assigned to one of three treatment groups. Six eyes (Control Group) had standard phacoemulsification only, nine eyes (Group 1) had standard phacoemulsification followed by capsular washing using intermediate settings (power = 40%, pulses per second [PPS] = 50, 30 s washing per capsule hemisphere), and nine eyes (Group 2) had standard phacoemulsification followed by aggressive capsular washing (power = 60%, PPS = 50, 60 s washing per capsule hemisphere). Results Control lens capsules had diffuse LECs remaining following standard phacoemulsification and complete ex vivo PCO formation (confluent LECs on the posterior capsule) within 4 ± 2 days (range 2–8 days). Group 1 lens capsules had focal, equatorial LEC clusters remaining following treatment, and complete PCO formation within 9 ± 2 days (range 5–11 days). Group 2 lens capsules had little to no LECs observed following treatment; 5 of 9 capsules had complete PCO formation within 13 ± 2 days (range 9–14 days), and 4 of 9 capsules had no PCO formation by 24 days post-treatment. Conclusions Pulsed fluid lens capsule washing is capable of removing LECs and delaying PCO formation in canine eyes following phacoemulsification ex vivo. Use of more aggressive capsular washing settings resulted in more effective LEC removal and subsequent delay of ex vivo PCO.

Purpose To characterize and describe the histopathologic findings in equine globes enucleated due to glaucoma. Methods Medical records at The Ohio State University from 1999 to 2012 were reviewed retrospectively. Signalment, history, and treatment data were collected, and histologic slides of enucleated globes were examined and lesions recorded. Twenty-three eyes from 23 horses were eligible for inclusion in this study. Results The majority of affected horses were > 15 years of age (65%). The ages ranged from 5 to 35 years (mean = 17.4 years). The left eye was affected in 10 cases (43%) and the right eye in 13 cases (57%). There were 13 mares (56%) and 10 geldings (44%). Quarter Horses (30%), Appaloosas (26%), and Thoroughbreds (22%) were the most common breeds in the study population. The most common histopathologic changes included hypercellularity of the optic nerve (93%), retinal atrophy (89%), corneal vascularization (83%), descemetization of pectinate ligaments (83%), hypercellularity of the anterior corneal stroma (75%), posterior bowing of the iris base (74%), ciliary body atrophy (74%), corneal striae (70%), pars plana elongation (60%), cataract (53%), and collapsed ciliary cleft/trabecular meshwork (52%). Evidence of uveitis (cataract, lymphoplasmacytic infiltration of the uvea, and/or anterior or posterior synechiae) was present in 20/23 eyes (87%). Conclusions Equine glaucoma most commonly occurs secondary to uveitis with Appaloosas and older horses predisposed. Histologic changes are comparable to prior reports of chronic glaucoma; notable findings not previously described in the horse were posterior bowing of the iris base and relative sparing of the superior retina from atrophy associated with elevated IOP.

PURPOSE Because hyaluronic acid (HA) is found in many surgical viscoelastic agents, this study aimed to determine (1) if HA receptors are present in the canine lens, (2) if the rate of lens epithelial cell (LEC) migration is altered following treatment with HA, and (3) if introduction of exogenous HA into the lens capsule promotes lenticular migration, thus contributing to posterior capsule opacification (PCO). METHODS Normal and cataractous canine LECs were evaluated for expression of the HA receptor CD44 and the receptor for HA mediated motility (RHAMM) using immunohistochemistry, immunoblotting, and real-time PCR. Canine LEC were treated with various concentrations of HA, and induction of migration was monitored over time. Commercially available surgical viscoelastics were utilized ex vivo, and rates of PCO formation were analyzed. RESULTS Basal protein and mRNA expression of both CD44 and RHAMM was noted. Cataractous canine LEC demonstrated significantly (P < 0.01) higher expression of CD44 but not RHAMM. Treatment with higher concentrations of HA resulted in a significant (P < 0.01) increase in CD44 mRNA and increased LEC migration in vitro. Use of CD44-neutralizing antibodies confirmed the role of CD44 in HA-induced lenticular migration. Viscoelastic material containing higher concentrations of HA led to increased rates of ex vivo PCO. CONCLUSIONS Exogenous HA can induce lenticular migration and CD44 expression. Use of surgical viscoelastics that contained HA resulted in increased rates of ex vivo PCO suggesting that judicious selection and use of viscoelastic material during cataract surgery is warranted.

To describe the long-term histologic and intraocular pressure (IOP) lowering effects of diode laser transscleral cyclophotocoagulation (TSCP) on the normal equine eye.Eight normal adult horses.TSCP was performed in one randomly assigned eye. Sixty spots were treated at settings of 1500 ms and 1500 mW. Two horses were randomly selected for euthanasia at 2, 4, 12, or 24 weeks post-TSCP. Both eyes were enucleated and histologically evaluated. Intraocular pressure was measured by applanation tonometry prior to TSCP, immediately post-TSCP, twice daily for 7 days post-TSCP and then monthly until study conclusion. A longitudinal model estimated the average IOP values for the treated and untreated eyes at 1 week, 1, 3, and 6 months post-TSCP.All treated eyes at all time periods exhibited four characteristic histologic lesions: scleral collagen hyalinization, ciliary body pigment dispersion and clumping, focal disruption of the ciliary body epithelium, and focal ciliary process atrophy. After TSCP, there were no significant changes in IOP from baseline for the control eyes, while the IOP in treated eyes was significantly decreased from baseline (P0.05) at all time periods. The estimated decrease in IOP in the treated eyes compared to baseline IOP at 6 months was -3.76 mmHg for an average decrease in IOP of 20% from baseline.Diode laser TSCP produces histologic lesions in the equine ciliary body that result in a significant and sustained decrease in IOP. TSCP may be an effective management for equine glaucoma.

Objective—To evaluate effect of adjunctive treatment with tetracycline analogues on time to complete corneal reepithelialization in dogs with nonhealing (ie, refractory) corneal ulcers. Design—Randomized controlled clinical trial. Animals—89 dogs with refractory corneal ulcers. Procedures—Corneal ulcers were treated via debridement and grid keratotomy. Dogs were assigned to receive 1 of 3 treatment regimens for up to 6 weeks: doxycycline (5 mg/kg [2.27 mg/lb], PO, q 12 h) with topically applied ophthalmic ointment containing neomycin, polymyxin B, and bacitracin (ie, triple antibiotic ointment; q 8 h); cephalexin (22 mg/kg [10 mg/lb], PO, q 12 h) with topically applied oxytetracycline ophthalmic ointment (q 8 h); or a control treatment of cephalexin (22 mg/kg, PO, q 12 h) with topically applied triple antibiotic ointment (q 8 h). Healing was monitored via measurements of the wound with calipers and evaluation of photographs obtained every 2 weeks. Treatment effectiveness was evaluated by wound healing and decreased signs of pain. Results—The Boxer breed was overrepresented in all groups. At the 2-week time point, wound healing was significantly more common in small-breed dogs, compared with large-breed dogs. Dogs treated with oxytetracycline ophthalmic ointment had a significantly shorter healing time than did dogs receiving the control treatment. Corneal ulcers in dogs that received doxycycline PO healed more rapidly than did ulcers in dogs in the control treatment group; however, this difference was not significant. Conclusions and Clinical Relevance—Topical tetracycline ophthalmic ointment was a safe, inexpensive, and effective adjunctive treatment for refractory corneal ulcers in dogs.

To evaluate the outcome of diode laser transscleral cyclophotocoagulation (TSCP) for the treatment of glaucoma in horses.Medical records at The Ohio State University were reviewed. All horses that underwent diode laser TSCP between the years of 1995 and 2007 were included. Preoperative, procedural and clinical follow-up data were collected, and telephone follow-up was performed.Forty-two eyes of 36 horses were included. Twenty-four hours prior to surgery mean intraocular pressure (IOP) was 37.17 + or - 13.48 mmHg (42 eyes). Forty-one of 42 eyes (98%) were sighted and 39 of 39 (100%) of eyes were receiving topical glaucoma medication. At 3-5 weeks postoperatively the average IOP was 19.36 + or - 12.04 mmHg (22 eyes). IOP remained significantly lower than pretreatment values at all periods of clinical follow-up (P0.05). There was no significant difference in vision outcome, or the requirement for topical glaucoma medication relative to pretreatment values at any follow-up period. Hyphema in 5 of 42 eyes was the only complication noted. Of the 27 eyes seen for clinical follow-up, 2 were enucleated because of refractory elevation of IOP. Mean telephone follow-up was 49 months. Twenty-one of 22 owners contacted (95%) reported that the treatment had been of value, 14 of 22 eyes (64%) were receiving topical glaucoma medication, and 13 of 22 eyes (59%) were considered sighted.Diode laser TSCP aided in the control of IOP and maintenance of vision but did not eliminate the need for topical glaucoma medication during the period of clinical follow-up.

Objective To determine the acute histologic effects of semiconductor diode laser transscleral cyclophotocoagulation (TSCP) on the normal equine eye. Animal studied Part 1: eight eyes of four horses. Part 2: 10 eyes of five horses. Materials and methods Part 1: TSCP was performed on four eyes at 4 mm and four eyes at 6 mm posterior to the limbus with 15 sites treated in four quadrants at 1800 mW for 1500 ms. The globes were sectioned transversely or sagitally to examine all quadrants and histologic sections were taken every 1 mm for the entire globe. Part 2: Based on the results from Part 1, TSCP was performed at 20 sites 4 mm posterior to the dorsotemporal limbus with a constant energy varying from 0.75 to 4 J/site. Histologic sections were taken every 1 mm for a total of 10 sections per eye and 20 sections per energy level group. Results Part 1: At 4 mm posterior to the limbus, coagulation of the nonpigmented epithelium (NPE) of the pars plicata was observed in the temporal (14%) and dorsal quadrants (12%). Retinal detachment was observed in the nasal quadrant (12%). Hemorrhage was common in the nasal (19%) and temporal (12%) quadrants. At 6 mm posterior to the limbus, coagulation of the NPE of the pars plicata was observed in the dorsal (14%), ventral (16%), nasal (2%), and temporal (2%) quadrants. Retinal detachment was observed in the dorsal (8%), ventral (18%), nasal (20%) and temporal (2%) quadrants. Part 2: Settings of 0.75 J/site were ineffective; 1.5, 2.25 and 3 J/site damaged the pars plicata without disruption of anatomy; and 4 J/site caused disruption of normal architecture. Conclusions The most appropriate site for equine TSCP appears to be 4 mm posterior to the dorso- and ventrotemporal limbus avoiding the 3 and 9 o’clock positions and using an initial energy setting of 2.25 J/site. This results in effective damage to the pars plicata while minimizing surgical complications such as retinal detachment and hemorrhage.

Posterior capsular opacification (PCO) is the most common postoperative complication of contemporary cataract surgery. Limited information is available regarding PCO formation and factors that influence PCO development in the dog. Two hundred sixty-five eyes (144 from diabetic dogs and 121 from dogs with breed-related cataracts) were prospectively evaluated for PCO formation for up to 12 months postoperatively. The mean age of all dogs in the study was 7.77 years and diabetic dogs were significantly older than dogs with breed-related cataracts. There were 73 males (61 neutered, 12 intact) and 74 females (70 neutered, 4 intact) in the study. Statistical analysis was performed based on age, breed/size, gender, stage of cataract at the time of surgery, PCO score at each time point, breed-related vs. diabetic cataract, right eyes compared to left eyes, and presence/absence of uveitis. Age and gender did not significantly influence PCO formation. Small and medium-sized breeds developed significantly more PCO in comparison to the large/giant breeds at 2 weeks and 2-4 months postoperatively, but the differences were not significant at later time points. There was an overall significant increase in PCO formation in eyes with early immature cataracts when compared to other stages of cataract up to 4 months postoperatively but not at later time points. There were no statistical differences in PCO score at 6 months or at 1 year postoperatively in eyes with breed-related and diabetic cataracts. Right eyes did not differ from left eyes in PCO score. PCO score significantly increased over time in breed-related and diabetic groups and in the overall population. No difference was found in the degree of PCO formation in eyes with inflammation prior to or after surgery compared with those without inflammation. In summary, age, gender, presence of inflammation, and cause of cataract (breed-related vs. diabetes mellitus) do not influence the development of PCO in canine cataract dogs. Small and medium-sized breeds develop significant PCO earlier than larger breeds. It is important to note that all eyes from all dogs in this study developed PCO in a time dependent manner.

The receptor for advanced glycation end-products (RAGE) increases in the human cataract and should correlate with increased DNA damage and proliferation of lens epithelial cells (LECs). The purpose of this study was to measure and immunolocalize RAGE in normal and cataractous canine LECs, and to determine whether there was a correlation between RAGE and DNA damage (gadd45), cell-cycle regulation (p21), and LEC proliferation (proliferating cell nuclear antigen, PCNA).Thirty-two anterior lens capsules from 22 dogs that underwent cataract surgery and 10 lenses from dogs with normal eyes were evaluated. Eleven of the cataractous lenses were from diabetic patients (n=16), and eleven were from patients with inherited cataracts (n=16). Standard immunohistochemical staining was performed using antibodies against RAGE, gadd45, p21, PCNA, alpha-smooth muscle actin, and TGF-beta. Immunostaining intensity for each antibody was given a score of 0-4+. Standard Western blot analysis on normal and cataractous lens capsules was performed using the same antibodies as in the immunohistochemical staining. Comparisons were also made based on age and sex. Real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) was performed for RAGE.There was an increase in RAGE expression with age in normal LECs, but no significant difference was seen when normal adult LECs were compared to cataractous LECs. The stage of the cataract and the presence of LIU were not associated with a significant increase in RAGE expression. There was no age-dependent difference in the normal lenses for gadd45, p21, or PCNA. Significant up-regulation of p21 (P0.05) and PCNA (P0.05) was seen in diabetic cataracts compared to inherited cataracts.RAGE and PCNA expression did not increase with cataractogenesis, possibly due to overexpression associated with normal aging and constant exposure to oxidative stress from sunlight-related ultraviolet irradiation, respectively. However, p21 and PCNA increased in diabetic cataractogenesis suggesting cell cycle and proliferation dysregulation. This may be related to the rapid onset in this type of cataract compared with the more chronic and slower-to-develop inherited cataracts.

Objective To describe semiconductor diode laser use for anterior uveal cyst deflation and coagulation in dogs, horses and cats. Animals studied The presenting clinical signs, surgical technique and postoperative results for four dogs, nine horses and seven cats with anterior uveal cysts treated with diode laser are described. Treated cysts were of sufficient size and/or number to potentially impair vision, damage the corneal endothelium, or increase intraocular pressure (IOP). One dog with free-floating cysts exhibited ‘fly biting’ behavior. Cysts were suspected of causing shying on the affected side and/or head-shaking behavior in seven horses. Cysts were free floating within the anterior chamber in dogs, occurred in the corpora nigrum in horses and were attached to the posterior iris surface in cats. In cats, shallowing of the anterior chamber and dyscoria were observed. In all cats prior to cyst deflation, IOP increased after pharmacologic pupil dilation. Cats were more likely than dogs and horses to have bilateral and multiple cysts. Procedure Two dogs and all horses were treated without general anesthesia and two dogs and all cats were treated under general anesthesia. Diode laser was used to perforate, deflate and coagulate the cysts. Results Postoperatively, all eyes were free of discomfort or significant inflammation and minimal or no topical or systemic anti-inflammatory therapy was required. Abnormal behavior improved or resolved in all cases. In all cats, IOP 24 h after photocoagulation was lower than the postdilation IOP. Cysts did not recur, but new cysts were discovered in several cases. Conclusion Semiconductor diode laser coagulation of anterior uveal cysts is safe, effective and noninvasive.