Diane V. H. Hendrix

Corneal transplantation for inflammatory keratopathies in the horse: visual outcome in 206 cases (1993-2007).

OBJECTIVE To evaluate the visual outcome of three techniques of corneal transplantation surgery in treating severe inflammatory keratopathies in the horse. DESIGN Retrospective medical records study. ANIMALS STUDIED Medical records of 206 horses that received corneal transplantation surgery at the University of Florida Veterinary Medical Center from 1993 to 2007 were reviewed. PROCEDURE Data collected from the medical records included signalment, types of ocular lesions, type of transplant surgery performed, length of follow-up, complications, and visual outcomes. RESULTS Full thickness penetrating keratoplasty (PK) was performed in 86 horses for melting ulcers, iris prolapse/descemetoceles, and medically nonresponsive full thickness stromal abscesses (SA). Posterior lamellar keratoplasty (PLK) and deep lamellar endothelial keratoplasty (DLEK) are split thickness penetrating keratoplasties that were utilized for medically nonresponsive deep stromal abscesses (DSA) in 54 and 66 eyes, respectively. The most common postoperative surgical complication was graft rejection and varying degrees of graft opacification. Wound dehiscence and aqueous humor leakage was also a common postoperative problem. A positive visual outcome was achieved for PK, PLK, and DLEK in 77.9%, 98.1%, and 89.4%, respectively. CONCLUSIONS Corneal transplantation is a tectonically viable surgery in the horse with an overall success rate of 88.5% in maintaining vision when treating vascularized and infected corneal disease in the horse.

Normal Ocular Parameters and Characterization of Ophthalmic Lesions in a Group of Captive Bald Eagles (Haliaeetus leucocephalus)

Abstract: Sixteen adult captive bald eagles (Haliaeetus leucocephalus) underwent a complete bilateral ocular examination to assess normal ocular parameters and describe ophthalmic lesions. Tear production was measured with the Schirmer tear test 1 and intraocular pressure was measured with applanation tonometry. The menace response was normal bilaterally in 13 of 16 eagles. Two birds had normal menace responses despite having fundic lesions, and 2 birds with an inconsistent or absent menace response did not have appreciable ophthalmic lesions. Mean (SD) tear production was 14 ± 2 mm/min (range, 8–19 mm/min). Mean intraocular pressure was 21.5 ± 1.7 mm Hg (range, 15–26 mm Hg). At least 1 ocular lesion was present in 50% of examined eyes. Cataracts, the most common lesion observed, were present in 8 eyes of 5 birds. Three of 4 known geriatric birds were or had been affected with bilateral cataracts. Overall, ocular lesions are common in captive bald eagles, and cataracts appear to be more prevalent in geriatric bald eagles. An obvious positive menace response is present in most visual birds but may be absent in some eagles that are either normal or that do not have appreciable ophthalmic lesions. Applanation tonometry and the Schirmer tear test 1 can be performed easily on adult bald eagles and provide reproducible results.

Malignant Teratoid Medulloepithelioma in a Llama

A lesion was identified in the eye of a juvenile llama, and preliminary clinical findings included anterior uveitis and an exudative retinal detachment suggestive of infectious disease. However, histopathologic evaluation of the enucleated globe revealed an intraocular neoplasm composed of primitive neuroepithelium forming ribbons, cords, and rosettes, heteroplastic elements including spindle cells in a loose myxomatous matrix, and islands of well-differentiated hyaline cartilage. Immunohistochemically, neoplastic cells were positive for vimentin and neuron-specific enolase. Spindle cells were multifocally positive for desmin and muscle specific actin, indicating differentiation towards myofibers. These findings are consistent with a diagnosis of malignant teratoid medulloepithelioma, an extremely rare ocular neoplasm that affects children and young animals.

Extraocular lymphoma in the horse

OBJECTIVE To describe the clinical findings and prognosis for extraocular lymphoma in the horse. PROCEDURES   Retrospective medical records study of horses diagnosed with third eyelid, corneoscleral, conjunctival, and/or eyelid lymphoma from multiple academic and private veterinary institutions. Data collected from the medical records included signalment, clinical descriptions of the extraocular lesions, treatment, and treatment outcomes. Nonparametric statistical analysis was performed with Fischers exact tests. RESULTS   Extraocular lymphoma involving the eyelid, third eyelid, cornea, sclera, and/or conjunctiva was diagnosed in 26 horses. Differences in signalment, unilateral vs. bilateral extraocular involvement, and single vs. multiple extraocular lesion locations held no significance in terms of outcome. ANIMALS STUDIED   Horses with lesions localized to the eyelid or other nonextraocular cutaneous locations had a significantly higher chance of negative outcome when compared to the horses with no eyelid or cutaneous involvement (P = 0.019). Lesions to the third eyelid, corneosclera, and conjunctiva were either nodular or diffuse in nature. Nodular lesions when compared to diffuse lesions were associated with a higher chance of a positive outcome (P = 0.007). Surgical resection of the extraocular lesions as part of the treatment produced a statistically higher chance of a positive outcome when compared to horses where resection was not performed (P = 0.03). CONCLUSIONS   The prognosis for clinical remission in horses with extraocular lymphoma is generally fair to good, as long as the affected tissues are completely excised, and there is no eyelid or cutaneous involvement. Horses diagnosed with the nodular form of extraocular lymphoma seem to have the best prognosis with complete excision.

Outcomes of dogs presented for cataract evaluation: a retrospective study.

Two hundred and forty-four dogs were evaluated for cataracts at the University of Tennessee from January 2001 to December 2002. Fifty-four canine breeds were affected. Odds ratios for cataracts were significantly higher for six purebred dogs (including the cocker spaniel, miniature schnauzer, toy poodle, Boston terrier, miniature poodle, and bichon frise) compared with mixed-breed dogs. One hundred fifty-nine dogs did not have cataract surgery. The most common reason for dogs not having surgery was retinal degeneration (n=66).

Detection of papillomavirus in equine periocular and penile squamous cell carcinoma

Squamous cell carcinoma (SCC) is the most common tumor arising in the periocular and penile areas of horses. Both ultraviolet radiation and papillomaviruses have been implicated in the pathogenesis of SCC in various species, including the horse. This retrospective study used polymerase chain reaction (PCR) to detect papillomavirus DNA in archival biopsy samples from equine periocular and penile SCC from 3 different geographic areas (northeast, southeast, and central United States). Forty-two periocular SCCs were tested; none contained papillomavirus DNA. Twenty-two penile SCCs were tested, and papillomavirus DNA was identified in 10 (43%) cases. Sequencing of the PCR products revealed homology with Equus caballus papillomavirus 2 (EcPV-2). No geographic distribution in the detection of papillomavirus was identified. Penile SCCs were significantly more likely to be papillomavirus positive than the periocular SCCs (P < 0.001). The role of papillomavirus in the development of penile SCC requires further investigation. The differing pathogeneses of periocular and penile SCC suggest that the tumors may respond differently to treatment.

The effect of a single dose of topical 0.005% latanoprost and 2% dorzolamide/0.5% timolol combination on the blood-aqueous barrier in dogs: a pilot study

OBJECTIVE To determine the effects of 0.005% latanoprost and 2% dorzolamide/0.5% timolol on the blood-aqueous barrier (BAB) in normal dogs. ANIMALS STUDIED Eight mixed-breed and pure-breed dogs. PROCEDURES Baseline anterior chamber fluorophotometry was performed on eight normal dogs. Sodium fluorescein was injected and the dogs were scanned 60-90 min post-injection. Seventy-two hours following the baseline scan, one eye received one drop of latanoprost. Fluorophotometry was repeated 4 h after drug administration. Following a washout period, the identical procedure was performed 4 h after the administration of dorzolamide/timolol. The degree of BAB breakdown was determined by comparing the concentrations of fluorescein within the anterior chamber before and after drug administration. BAB breakdown was expressed as a percentage increase in the post-treatment fluorescein concentration over the baseline concentration: %INC [Fl] = {([Fl](post)-[Fl](baseline))/[Fl](baseline)} x 100. The percentage increase in fluorescein concentration in the treated eye was compared to that in the nontreated eye using a paired t-test with significance set at P < or = 0.05. RESULTS Following administration of latanoprost, the fluorescein in the treated eyes increased 49% (+/- 58%) from baseline compared to 10% (+/- 31%) in the untreated eyes (P = 0.016). Following administration of dorzolamide/timolol, the fluorescein concentration increased 38% (+/- 54%) compared to baseline vs. 24% (+/- 38%) in the untreated eyes (P = 0.22). CONCLUSIONS The results of this study show that topical latanoprost may cause BAB disruption in normal dogs while topical dorzolamide/timolol may have no effect on the BAB in normal dogs.

An investigation comparing the efficacy of topical ocular application of tacrolimus and cyclosporine in dogs.

The purpose of this paper was to determine the efficacy and safety of topical tacrolimus, compared to cyclosporine, for treating keratoconjunctivitis sicca (KCS) in dogs. This study was a two-phase, randomized, controlled, masked clinical trial. Phase 1 evaluated ophthalmic 0.03% tacrolimus in normal dogs. Ocular examinations were performed daily. Phase 2 evaluated the efficacy of tacrolimus in treating KCS. Half the dogs received 2% cyclosporine A; the others received 0.03% tacrolimus, both diluted in olive oil. Four ophthalmic examinations were done over 12 weeks. There was no significant difference between groups in phase I. In phase 2, there was no significant difference in Schirmer tear test I (STT) results between the two groups, and both groups had a significant increase in STT over time. Both drugs were effective in increasing the STT in dogs naïve to lacrimostimulants. Tacrolimus was effective in increasing the STT in 4 dogs currently nonresponsive to cyclosporine.

Long-term evaluation of the use of Ahmed gonioimplants in dogs with primary glaucoma: nine cases (2000-2008).

OBJECTIVE To evaluate the outcome and describe the complications associated with use of an Ahmed gonioimplant in the treatment of glaucoma in dogs. DESIGN Retrospective case series. ANIMALS 9 client-owned sighted dogs (median age, 9 years) with primary glaucoma. Procedures-Medical records of dogs with primary glaucoma that underwent unilateral gonioimplant placement (in 2000 through 2008), during which a temporalis muscle fascia graft (n = 8) or porcine intestinal submucosa (1) was used to cover the implant tube as it exited the globe, were reviewed. All dogs were treated with mitomycin C in the conjunctival pocket intraoperatively and with tissue plasminogen activator immediately after surgery; 1% prednisolone acetate was applied to the implanted eye daily until failure of the implant. Medical intervention or additional surgery was performed when intraocular pressures (IOPs) were > 20 mm Hg or progressively increasing values were detected. RESULTS After gonioimplant placement, IOP was controlled for a variable period in all dogs. Subsequently, IOP exceeded 20 mm Hg in 7 dogs (median postoperative interval, 326 days). Median interval to vision loss despite interventional surgery was 518 days (range, 152 to 1,220 days). Surgical intervention was necessary in 4 dogs to maintain satisfactory IOP. Implant extrusion attributable to conjunctival dehiscence or necrosis occurred in 4 dogs. At 365 days after surgery, 8 dogs retained vision, and 5 dogs retained vision throughout follow-up. CONCLUSIONS AND CLINICAL RELEVANCE In dogs with medically refractory primary glaucoma, placement of a gonioimplant appears to be effective in maintaining vision.

Effects of one-week versus one-day preoperative treatment with topical 1% prednisolone acetate in dogs undergoing phacoemulsification

OBJECTIVE To compare the effects of 2 preoperative anti-inflammatory regimens on intraocular inflammation following phacoemulsification. DESIGN Randomized controlled trial ANIMALS 21 dogs with immature cataracts. PROCEDURES All dogs had cataract surgery via phacoemulsification, and most received prosthetic intraocular lenses. Dogs were randomly divided into 2 groups. Group A dogs were treated topically with prednisolone acetate for 7 days prior to surgery, whereas prednisolone acetate treatment commenced the evening prior to surgery in group B dogs. Postoperative care was identical for both groups. Blood-aqueous barrier breakdown was quantified by use of anterior chamber fluorophotometry, with fluorescein entry into the anterior chamber measured 2 and 9 days after surgery compared with baseline scans obtained prior to surgery. Ophthalmic examinations were performed before surgery and 1 day, 9 days, 3 weeks, 7 weeks, 3 months, and 6 months after surgery. A subjective inflammation score was established at each examination. Intraocular pressures were measured 4 and 8 hours after surgery and at each follow-up examination. RESULTS There was no difference in the extent of blood-aqueous barrier disruption between the groups at 2 or 9 days after surgery. Subjective inflammation scores were also similar at most time points. Dogs in group A developed postoperative ocular hypertension at a higher frequency (60%) than did those in group B (18%). CONCLUSIONS AND CLINICAL RELEVANCE In dogs that underwent cataract surgery via phacoemulsification, a full week of topical prednisolone acetate treatment prior to surgery did not decrease postoperative inflammation, compared with commencement of topical prednisolone acetate treatment the evening prior to surgery, and was associated with a greater incidence of postoperative ocular hypertension.