Objective—To characterize heritability and mode of inheritance of cataracts and primary lens luxation in Jack Russell Terriers.
Animals—872 Jack Russell Terriers from which buccal epithelial cells were collected and phenotypes for cataracts and lens luxation were determined and an additional 1,898 Jack Russell Terriers without phenotypic information used to complete pedigree relationships and that were included in the analyses.
Procedures—Narrow-sense heritabilities and genetic correlation for cataracts and lens luxation were modeled by use of threshold analysis, whereas complex segregation analysis was used to characterize mode of inheritance. For the analyses, dogs < 6 years old, unless confirmed as having cataracts or lens luxation, were classified as an unknown phenotype. The possible involvement of an HSF4 mutation in cataracts was determined by DNA sequencing.
Results—Cataracts and primary lens luxation were highly heritable and genetically correlated, and neither was controlled by a single gene. Cataracts were not associated with an HSF4 mutation.
Conclusions and Clinical Relevance—Analysis of the data indicated that concerted selection against both cataracts and primary lens luxation when choosing breeding animals can be used to improve ocular health in Jack Russell Terriers.
Objective—To describe clinical and diagnostic imaging features of zygomatic sialadenitis in dogs.
Design—Retrospective case series.
Animals—11 dogs with zygomatic sialadenitis and 20 control dogs without evidence of retrobulbar disease.
Procedures—Medical records were searched for dogs with zygomatic sialadenitis that underwent some combination of magnetic resonance imaging (MRI), computed tomography (CT), and ultrasonography. Signalment, clinical signs, results of clinicopathologic tests, cytologic and histologic diagnosis, treatment, qualitative disease features, and disease course were recorded. Images obtained via MRI or CT were analyzed for pre- and postcontrast signal intensity or density, respectively; zygomatic salivary gland area was determined. Results were compared with those of control dogs that underwent the same imaging procedures (n = 10/method). Ultrasonographic images of affected dogs were assessed qualitatively.
Results—Most (9/11) affected dogs were medium- or large-breed males (mean age, 8 years) with unilateral disease. Affected dogs had clinical signs of retrobulbar disease and cytologic or histologic evidence of zygomatic sialadenitis. Sialoceles were detected in 7 affected glands. Compared with values for control dogs, MRI findings in affected dogs (n = 7) included gland enlargement, T1-weighted hypointensity, T2-weighted hyperintensity, and increased contrast enhancement; CT features in affected dogs (2) included gland enlargement and hypodensity on unenhanced images. Retrobulbar masses were identified via ultrasonography in 9 of 10 orbits examined, and zygomatic salivary gland origin was detected in 4.
Conclusions and Clinical Relevance—Visualization of anatomic structures for diagnosis of zygomatic sialadenitis and evaluation of adjacent structures was excellent via MRI and CT Ultrasonography was less definitive but useful for sample collection.
Objective—To compare aesthesiometer-determined
corneal sensitivity between diabetic and nondiabetic
dogs and to investigate the correlation between
corneal sensitivity and duration of diabetes or status
of glycemic control, as estimated by use of glycated
blood protein concentrations.
Animals—23 diabetic and 29 nondiabetic normoglycemic
Procedure—A Cochet-Bonnet aesthesiometer was
used to measure corneal touch threshold (CTT) in 5
corneal regions of each dog. At the time of ocular
examination, duration of diabetes mellitus was estimated
from the history, and blood was drawn for
assessment of blood glycosylated hemoglobin and
serum fructosamine concentrations.
Results—Median CTT for central, nasal, dorsal, temporal,
and ventral corneal regions in nondiabetic dogs
(1.6, 2.3, 2.8, 2.8, and 5.1 g/mm2, respectively) was
significantly lower than in diabetic dogs (2.8, 4.0, 5.1,
5.1, and 6.6 g/mm2, respectively). Median regional
CTT in diabetic dogs was not significantly correlated
with estimated duration of diabetes mellitus or blood
glycated protein concentrations. No significant difference
was found in regional CTT between eyes of normoglycemic
dogs with unilateral cataracts.
Conclusion and Clinical Relevance—Diabetic dogs
have significantly reduced corneal sensitivity in all
regions, compared with nondiabetic normoglycemic
dogs. Regional variation in corneal sensitivity is similar
in diabetic and normoglycemic dogs. Neither
glycemic control nor duration of diabetes, as estimated,
is significantly correlated with corneal hyposensitivity.
Corneal nerve dysfunction may be associated
with recurrent or nonhealing ulcers in diabetic dogs
for which no other underlying cause can be found.
(Am J Vet Res 2003;64:7–11)
Objective—To measure the effect of induced myopia on field trial performance in dogs.
Animals—7 Labrador Retrievers and 1 Chesapeake Bay Retriever trained in field trial competition.
Procedures—Dogs were commanded to retrieve targets at 137.2 m (150 yards). Each dog participated in 3 trials while their eyes were fitted with 0- (plano), +1.50-, or +3.00-diopter (D) contact lenses, applied in random order. Retrieval times were measured objectively, and dog performances were evaluated subjectively by masked judges.
Results—Retrieval times were significantly faster with plano lenses than with +1.50- or +3.00-D lenses, but there were no significant differences in times between +1.50- and +3.00-D lenses. Masked judges assigned the best performance scores to dogs with plano lenses and the lowest scores to dogs fitted with +3.00-D lenses.
Conclusions and Clinical Relevance—Even mild myopic defocusing had a significant negative impact on both the subjective and objective assessments of dogs' performances. Dogs with demanding visual tasks or signs of visual deterioration should be evaluated retinoscopically to determine the refractive state because they may have ametropia.
Objective—To assess the effects of ketamine hydrochloride, propofol, or compounded thiopental sodium administration on intraocular pressure (IOP) and qualities of induction of and recovery from anesthesia in horses.
Animals—6 healthy adult horses.
Procedures—Horses were sedated with xylazine hydrochloride (0.5 mg/kg), and anesthesia was induced with guaifenesin followed by ketamine (2 mg/kg), propofol (3 mg/kg), or thiopental (4 mg/kg) in a crossover study with ≥ 1 week between treatments. For each horse, IOP in the right eye was measured with a handheld applanation tonometer before and after xylazine administration, at the time of recumbency, and every 3 minutes after induction of anesthesia until spontaneous movement was observed. Cardiorespiratory responses and venous blood measurements were recorded during anesthesia. Induction of and recovery from anesthesia were subjectively evaluated by investigators who were unaware of the anesthetic treatment of each horse. Data were analyzed via a repeated-measures ANOVA with Holm-Ŝidák post hoc comparisons.
Results—Compared with findings after xylazine administration (mean ± SD, 17 ± 3 mm Hg), thiopental decreased IOP by 4 ± 23%, whereas propofol and ketamine increased IOP by 8 ± 11% and 37 ± 16%, respectively. Compared with the effects of ketamine, propofol and thiopental resulted in significantly lower IOP at the time of recumbency and higher heart rates at 3 minutes after induction of anesthesia. No other significant differences among treatments were found.
Conclusions and Clinical Relevance—These findings support the use of thiopental or propofol in preference to ketamine for horses in which increases in IOP should be minimized.
Objective—To compare client perception of outcome of phacoemulsification in dogs with information obtained from medical records.
Design—Retrospective cohort study.
Animals—108 dogs (203 eyes) undergoing phacoemulsification from May 1999 through April 2004.
Procedure—Data obtained from medical records included signalment, presence of diabetes mellitus, cataract stage, whether surgery was unilateral or bilateral, intraocular lens (IOL) placement, and postoperative complications. Owners completed a survey concerning outcome of phacoemulsification in their dog. Survey responses from owners classified as satisfied or dissatisfied with the outcome of phacoemulsification on the basis of their willingness, in retrospect, to have the surgery performed again were compared.
Results—Data from medical records and survey responses were available for 108 dogs (203 eyes). Median follow-up was 3 months via medical record review and 12 months via owner survey responses. Most (81%) owners were satisfied with outcome. The most common reason for dissatisfaction was loss of vision after surgery; however, most dissatisfied owners did not return their dog for examinations. Owner perception of success was not associated with patient age, sex, presence of diabetes mellitus, cataract stage, or IOL placement in at least 1 eye but was associated with perceived improvement of their pet's vision and activity level. Dissatisfied owners were significantly more likely to report that explanation of risks and complications before surgery was inadequate.
Conclusions and Clinical Relevance—Owner perception of outcome after phacoemulsification in dogs was highly favorable. However, surgical risks and the importance of postoperative examinations, particularly in dogs undergoing visual deterioration, must be conveyed to clients.
Objective—To determine the distribution and clinical outcome of ocular lesions in snakes.
Design—Retrospective case series.
Animals—67 snakes with ocular lesions.
Procedures—Signalment, lesion duration, diagnosis, treatment, and clinical outcome were recorded for all snakes with ocular lesions that were examined at a veterinary teaching hospital from 1985 to 2010.
Results—71 ocular lesions were detected in 67 of 508 (13%) snakes examined. Affected snakes were of the families Boidae, Pythonidae, Colubridae, and Viperidae. The distribution of ocular lesions did not vary by taxonomic family, age, or sex; however, snakes from the genus Epicrates with ocular lesions were overrepresented in the population. The most commonly diagnosed ocular lesions were retained spectacle (n = 41), pseudobuphthalmos or subspectacular abscess (13), trauma (8), and cataracts (4). Pseudobuphthalmos or subspectacular abscess developed more frequently in Colubridae than in non-Colubridae snakes. Of the 16 snakes with retained spectacles for which data were available, the lesion recurred once in 4 snakes and multiple times in 5 snakes.
Conclusions and Clinical Relevance—Results indicated that retained spectacle was the most common ocular lesion diagnosed in snakes. Compared with other snakes with ocular lesions, snakes of the genus Epicrates had a higher than expected frequency of ocular lesions in general and snakes of the family Colubridae had a higher than expected frequency of pseudobuphthalmos or subspectacular abscess.
PROCEDURES After collection of baseline clinical and historical data, dogs were randomly assigned to receive topically applied undiluted heterologous serum (n = 22) or isotonic saline (0.9% NaCl) solution (19) along with tobramycin and atropine. Epithelial debridement (at all visits) and grid keratotomy (at visits 2, 3, and 4) of SCCEDs were performed. Ophthalmic examination including fluorescein application was performed once weekly for 4 weeks or until corneal reepithelialization. Clinicians and owners were masked to treatment group.
RESULTS No differences in baseline data were detected between treatment groups. No difficulties with medication administration, noncompliance, or adverse reactions were noted. All SCCEDs in both groups healed by 4 weeks after treatment began. Median time to reepithelialization (2 weeks) was not significantly different between serum-treated and placebo-treated eyes. Irrespective of treatment group, median time to reepithelialization was not significantly different for Boxers versus non-Boxer breeds. Direct correlations were detected between time to reepithelialization and vascularization score at study entry, vascularization score at time of reepithelialization, and ulcer area at study entry in both groups. Time to reepithelialization was not correlated with age, sex, or duration of signs in either group.
CONCLUSIONS AND CLINICAL RELEVANCE Topical application of undiluted heterologous serum was well tolerated by dogs with SCCEDs but, as an adjunct to standard treatment, did not reduce time to corneal reepithelialization.
OBJECTIVE To describe diagnosis, treatment, and outcome of and risk factors for ophthalmic disease in leopard geckos (Eublepharis macularius) evaluated at a veterinary teaching hospital.
DESIGN Retrospective case series.
ANIMALS 112 of 144 (78%) leopard geckos that were evaluated at a veterinary teaching hospital in January 1985 through October 2013 and for which sufficient medical record information was available.
PROCEDURES Information from medical records was used to identify leopard geckos with ophthalmic disease, characterize cases, and determine risk factors for the presence of ophthalmic disease.
RESULTS Of the 112 leopard geckos, 52 (46%) had ophthalmic disease (mainly corneal or conjunctival disease). Female geckos were less likely to have ophthalmic disease, and there was a positive association between increasing age and ophthalmic disease. Use of a paper towel substrate, absence of any heat source, and lack of vitamin A supplementation were positively associated with a diagnosis of ophthalmic disease. Head dysecdysis was the only concurrent disorder significantly associated with ophthalmic disease. At necropsy, 5 affected leopard geckos had squamous metaplasia of the conjunctivae.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ophthalmic disease is a common finding in leopard geckos. The cause of ocular surface disease in leopard geckos may be multifactorial, and hypovitaminosis A may be an important risk factor. Although animals receiving supplemental vitamin A were less likely to have ophthalmic disease, further understanding is required regarding the metabolism of and nutritional requirements for vitamin A in leopard geckos.
Objective—To measure the dimensions of the eyes of living snakes by use of high-frequency ultrasound imaging and correlate those measurements with age, length, and weight.
Animals—14 clinically normal snakes.
Procedures—Species, age, length, weight, and horizontal spectacle diameter were recorded, and each snake underwent physical and ophthalmic examinations; ultrasonographic examination of both eyes was performed by use of a commercially available ultrasound unit and a 50-MHz transducer. Ultrasonographic measurements included spectacle thickness, subspectacular space depth, corneal thickness, anterior chamber depth, lens thickness, vitreous cavity depth, and globe length. All measurements were made along the visual axis.
Results—2 corn snakes, 5 California king snakes, 1 gopher snake, and 6 ball pythons were examined. There were no significant differences within or between the species with regard to mean spectacle thickness, corneal thickness, or subspectacular space depth. However, mean horizontal spectacle diameter, anterior chamber depth, and axial globe length differed among the 4 species; for each measurement, ball pythons had significantly larger values than California king snakes.
Conclusions and Clinical Relevance—Spectacle thickness, subspectacular space depth, and corneal thickness were similar among the species of snake examined and did not vary significantly with age, length, or weight. Measurements of these dimensions can potentially serve as baseline values to evaluate snakes of these species with a retained spectacle, subspectacular abscess, or subspectacular fluid accumulation. Anterior chamber depth and axial length appeared variable among species, but axial length did not vary with age, length, or weight in the species studied.