Determination of Schirmer tear test-1 values in clinically normal alpacas (Vicugña pacos) in North America.

PURPOSE: To determine the normal reference range for Schirmer tear test-1 (STT-1) values in eyes of healthy alpacas (Vicugña pacos). METHODS: Complete ophthalmic examinations were performed on forty healthy alpacas (80 eyes). STT-1 values were obtained in both eyes of all alpacas using a commercial STT strip of a single lot number. Data were analyzed, using a doubly repeated measures ANOVA design, Student's paired t-test, and Pearson correlation test, with P ≤ 0.05 considered significant. RESULTS: The STT-1 values ± standard deviation (SD) were 20.80 ± 4.01 mm/min OD, 20.00 ± 4.13 mm/min OS, and 20.88 ± 4.04 mm/min OU (range 15.50-30.50 mm/min). No significant differences in STT-1 were found between OD and OS. STT-1 was not significantly affected by breed. Schirmer tear test-1 values were significantly increased by 3.45 mm/min for every 10 year increase in age. CONCLUSIONS: This study provides a reference range of STT-1 in the healthy alpaca which can assist veterinarians in diagnosing potential keratoconjunctivitis sicca, tear film abnormalities, as well as ocular surface diseases in alpacas.

Comparison of intraocular pressure measurements using rebound (TonoVet® ) and applanation (TonoPen-XL® ) tonometry in clinically normal alpacas (Vicugña pacos).

PURPOSE: To evaluate intraocular pressure (IOP) estimates in eyes of healthy alpacas (Vicugña pacos) using rebound (TonoVet® ) in comparison with applanation (TonoPen-XL® ) tonometry. METHODS: Complete ophthalmic examinations were performed on forty healthy alpacas (80 eyes). IOP measurements using both TonoVet® and TonoPen-XL® tonometers were obtained OU. Data were analyzed, using a doubly repeated-measures anova design and Student's paired t-test, with P ≤ 0.05 considered significant. RESULTS: The mean IOP values ±SD via rebound tonometry were 14.20 mm ± 2.58 mm OD, 14.22 mm ± 2.90 mm OS, and 14.21 ± 2.73 mmHg OU (range 8.67-20.67 mmHg). The IOP values ±SD via applanation tonometry were 12.49 ± 2.81 mmHg OD, 12.53 ± 2.79 mmHg OS, and 12.51 ± 2.78 mmHg OU (range 6.00-19.33 mmHg). There was a significant difference (P = 0.002) in the IOP obtained between the tonometers, with the rebound tonometer having a 1.7 mmHg (0.69-2.71 mmHg, 95% confidence interval (CI)) higher IOP compared to the applanation tonometer. No significant differences in IOP were found between OD and OS. Age, gender, and breed did not significantly affect IOP values. CONCLUSIONS: IOP readings from the rebound tonometer were statistically higher than those from the applanation tonometer; however, this is not considered clinically significant. The accuracy of rebound tonometry in diseased alpaca eyes remains to be determined.

Carbon dioxide (CO2) laser third eyelid excision: surgical description and report of 7 cases.

PURPOSE: To describe a novel technique for third eyelid (TEL) excision using a carbon dioxide (CO2) laser. STUDY DESIGN: Prospective. ANIMALS STUDIED: The procedure was performed on six canine patients and one feline patient. METHODS: The laser was set to 6 Watts (W) of power and a linear continuous setting. Forceps were used to elevate the TEL and, with a protective shield covering the cornea, the base was cut and cauterized simultaneously. Minimal to no hemorrhage was observed, and the conjunctiva was left to heal by second intention. RESULTS: Seven patients underwent unilateral surgical TEL excision. All patients had suspected neoplasms affecting either the glandular tissues or conjunctival surfaces of the TEL. Clean surgical margins were achieved in all but one patient. All surgical sites were considered healed by 14 days showing mild-to-moderate conjunctival hyperemia and accumulation of mucoid discharge at the ventronasal fornix. One patient experienced postoperative keratoconjunctivitis sicca. Prolapse of orbital fat was not observed in any patient. CONCLUSION: Use of CO2 laser appears to be an efficient and effective means for surgical third eyelid removal with excellent postoperative comfort and minimal complications.

Corneal dystrophy in Friesian horses may represent a variant of pellucid marginal degeneration.

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.

Efficacy of prophylactic antiglaucoma and anti-inflammatory medications in canine primary angle-closure glaucoma: a multicenter retrospective study (2004-2012).

PURPOSE: To evaluate long-term efficacy of antiglaucoma medications with or without combined topical anti-inflammatory treatment in preventing increased intraocular pressure and clinical signs of glaucoma in eyes considered at risk of the development of the disease. METHODS: Retrospective analysis identified 88 canine patients presenting with unilateral acute congestive primary angle-closure glaucoma (IOP > 25 mm Hg) and gonioscopic findings of pectinate ligament dysplasia and/or narrow or closed iridocorneal angle in the contralateral nonglaucomatous eye. Patients with histopathologic confirmation of pectinate ligament dysplasia or angle closure in the initial glaucomatous eye receiving prophylactic medical therapy in the contralateral eye were included. Time to medical failure for each antiglaucoma medication and efficacy of the combination therapy were evaluated. RESULTS: The most commonly affected pure-breds were the American Cocker Spaniel (20.4%) and Basset Hound (11.36%). The patients receiving demecarium bromide 0.125% had the longest estimated median time to medical failure at 330.0 days, followed by latanoprost 0.005%, dorzolamide hydrochloride 2.0%, and demecarium bromide 0.25% at 284.0 days, 272.5 days, and 143.0 days, respectively. The estimated median time to medical failure for patients receiving topical antiglaucoma and anti-inflammatory medication was 324.0 days versus 195.0 days in patients receiving antiglaucoma medication alone. Survival analysis showed no statistical significance. CONCLUSIONS: None of the four antiglaucoma medications evaluated statistically delayed medical failure when compared to each other. Although significance was not achieved, our data suggest that adjunctive use of topical anti-inflammatory medications may be beneficial in these cases.

Evaluation of intraorbital prosthetic pigmentation using 0.3 and 1.5 Tesla magnetic resonance imaging and computed tomography.

PURPOSE: To investigate the magnetic susceptibility artifact associated with pigmented intraorbital prosthetics when performing magnetic resonance imaging (MRI) and computed tomography (CT). Potential artifact reduction techniques were also investigated. STUDY DESIGN: Prospective study. METHODS: Five different-colored 20-millimeter small animal silicone intraorbital prosthetics and two equine prosthetics were evaluated using 0.3 and 1.5 Tesla (T) MRI and CT. MRI sequences included T1- (T1WI) and T2-weighted spin echo (T2WI), T2 gradient echo (T2*), short tau inversion recovery (STIR), and fluid-attenuated inversion recovery (FLAIR). When present, artifact size was measured using computerized software by three separate observers. Artifact reduction techniques included alterations in receiver bandwidth, field of view, slice thickness, and matrix size. RESULTS: The ferrous brown-pigmented prosthetic resulted in a magnetic susceptibility artifact with MRI. No artifact was observed on CT images. Interobserver variability was not statistically significant. For both the 0.3T and 1.5T MRI, the T2* sequence exhibited the largest artifact surface area followed by T2WI, T1WI, STIR, and FLAIR. Decreasing slice thickness showed a decrease in artifact size; however, this difference was not statistically significant. CONCLUSIONS: The ferrous substances in the brown intraorbital prosthetic resulted in a significant magnetic susceptibility artifact when performing MRI. Artifact reduction techniques did not significantly decrease artifact surface area. The use of ferrous brown-pigmented prosthetics and their potential to affect future MR imaging studies should be adequately discussed with pet owners.

Presumptive electric cataracts in a Great Horned owl (Bubo virginianus).

This case report describes suspected electrocution in a juvenile female Great Horned owl (Bubo virginianus) with subsequent bilateral cataract formation. The bird flew into a high-voltage power line and was immediately rescued. Burn wounds of the head and ataxia with apparent blindness were noted. Initial ophthalmic examination 5 days after the incident revealed bilaterally symmetrical anterior subcapsular vacuolar cataracts with absence of intraocular inflammation and a predominantly clear view to the normal appearing fundus. The bird appeared to be nonvisual. No ophthalmic medications were prescribed at initial examination. Subsequent recheck examination at 8 weeks revealed moderate resolution of the cataracts and improved vision. To the authors' knowledge, this is the first published report of suspected electric cataracts in an avian species.

An unusual case of ocular melanosis and limbal melanocytoma with benign intraorbital extension in a dog.

This case report describes concurrent ocular melanosis and limbal melanocytoma in a 6-year-old Golden Retriever dog. Three years prior, the pet was examined for progressive corneal pigmentation and started on topical Tacrolimus but was subsequently lost to followup. Current ophthalmic examination revealed a large pigmented limbal mass and severe corneal pigmentation of the left eye as well as a small focal raised pigmented mass of the right third eyelid. Due to extent and rapidity of tumor growth, the left eye was removed via transconjunctival enucleation and submitted for histopathologic examination. At the time of surgery, numerous orbital structures including intraorbital fat, extraocular muscles, and portions of the proximal nasolacrimal drainage apparatus contained multifocal areas of black pigmentation. These tissues were subsequently removed and submitted for microscopic analysis. The pigmented mass of the right third eyelid was also excised. Histopathology of the left eye and orbital contents revealed a limbal melanocytoma extending to the bulbar conjunctiva and orbital space forming a large, markedly necrotic mass. Diffuse, severe ocular melanosis, abnormal stromal pigmentation of the sclera and orbital tissues, and corneal stromal pigmentation were noted. The mass of the right third eyelid was confirmed to be a conjunctival melanocytoma. To the authors' knowledge, this is the first report of concurrent ocular melanosis and limbal melanocytoma with orbital infiltration. The peculiar multifocal distribution of melanocytes throughout ocular connective tissues may explain the development of multiple melanocytic lesions in this patient.

Magnetic resonance imaging susceptibility artifact due to pigmented intraorbital silicone prosthesis.

Magnetic resonance imaging (MRI) findings of two cases with intracranial disease and pigmented intraorbital prosthetics are presented. A brown prosthetic (Case 1) caused a significant magnetic susceptibility artifact, which necessitated removal to properly image the brain. The artifact observed on MRI images is likely due to ferromagnetic pigments used for coloring. A black prosthetic (Case 2) caused no imaging artifact. The carbon-based pigments used to color the black prosthetic implant do not appear to cause imaging artifact. The pigments currently used to color the brown pigmented orbital prostheses cause significant magnetic susceptibility artifact and may require removal to evaluate the brain and surrounding structures completely.

Modified evisceration technique in a golden eagle (Aquila chrysaetos).

Two different modified techniques have been described for enucleation in raptors, including the transaural approach and the globe-collapsing procedure. This case report describes an alternative, modified evisceration procedure in a mature female Golden Eagle (Aquila chrysaetos). The advantages of this procedure are decreased anesthetic time, ease of procedure, decreased risk of excessive traction of the optic nerve, decreased intraoperative orbital trauma, and preservation of the natural symmetry of the head. The major disadvantage of this procedure is that it does not allow complete histologic examination of the globe. Patients with intraocular infection or neoplasia, or significant orbital disease may be poor candidates for this technique.