Objective Sudden acquired retinal degeneration syndrome (SARDS) is a leading cause of irreversible blindness in dogs, yet no treatment has been objectively evaluated, or proven to be effective. Consensus of opinion is that SARDS is immune-mediated, although corticosteroid medications may exacerbate associated systemic signs. We examined the effect of sole-agent treatment with mycophenolate mofetil (MMF), a potent immunosuppressive medication unlikely to exacerbate associated systemic signs. Animals studied Procedures Ten client-owned dogs with SARDS prospectively recruited within 6 weeks of vision loss. Clinical history, findings of systemic and ophthalmic examinations, blood parameters, visual navigation ability, electroretinography, and optical coherence tomography (OCT) were collected at baseline and at recheck after approximately 6 weeks of treatment with 10 mg/kg q 12 h of oral MMF. Results Conclusions Twenty percent of dogs (2/10) experienced side effects (diarrhea, vomiting, lethargy), which resolved with reduction in dose to 8 mg/kg q12 h. No significant changes in systemic signs, physical examination findings, or laboratory test results were detected at the recheck examination. Compared with baseline, visual ability significantly declined at the recheck examination, and the amplitude of a slow-onset negative waveform noted on dark-adapted electroretinography was reduced at the recheck examination. The outer retinal layers were significantly thinner at the recheck examination as measured by OCT. Mycophenolate mofetil as a sole agent has no measureable positive effect on physical health, vision, or retinal structure following a 6-week trial period. Further studies are needed to evaluate other treatment options for SARDS.
Objective To estimate the prevalence of ocular disease and obtain normative ocular data for free-living hummingbirds. Animals studied Two hundred and sixty-three free-living, adult Hummingbirds from coastal and inland central California were studied, including Anna's (Calypte anna, n = 186) and Black-chinned (Archilochus alexandri; n = 77) hummingbirds. Procedures Slit lamp biomicroscopy and indirect ophthalmoscopy were performed on all individuals. Rebound tonometry, measurement of horizontal palpebral fissure length, and streak retinoscopy were performed on select individuals. Five conscious Anna's Hummingbirds underwent ocular imaging including fundus photography, digital slit lamp photography, and anterior segment and retinal optical coherence tomography. Results The prevalence of ocular disease in this population was 2.28%. Ocular imaging revealed a thin cornea, shallow anterior chamber, large lens, and a single central, deep convexiclivate fovea. Mean +/- SD intraocular pressure was 11.21 +/- 2.23 mm Hg. Mean +/- SD eyelid length was 2.59 +/- 0.19 mm. All eyes were emmetropic or mildly hyperopic with a mean (range) +/- SD refractive error of +0.32 (-0.25 to +1) +/- 0.33 diopters. Conclusions Consistent with previous reports, these data suggest that hummingbirds have visual characteristics found in predatory and prey species, as well as a low prevalence of spontaneous ocular disease. This work provides a set of reference values and clinical findings that can be used in the future research on hummingbird vision and ocular disease. It also provides representative diagnostic images of normal birds and demonstrates that advanced ocular imaging can be performed on manually restrained hummingbirds without pharmacologic dilation.
Objective To characterize the bacterial community residing on the conjunctiva of clinically healthy dogs. Methods Bacterial DNA from conjunctival swabs of 10 dogs with normal ocular examinations (both OD and OS, n = 20) was extracted, and 16S rRNA amplicons were sequenced using Illumina MiSeq 600. Resulting data were subjected to quality control steps, and analyzed for bacterial community richness and diversity, within- and between-group dissimilarity, and relative taxonomic composition. Results High-quality reads (2.22 million bp) resulted in a mean of 159 068 sequences per sample. Bacterial community evenness and diversity was high when compared to other species, and did not significantly differ when samples were grouped by dogs or eyes. As expected, within-dog samples were more similar than between-dog samples. Taxonomic classification revealed that >95% of the community consisted of Firmicutes (34.9 +/- 8.8%), Actinobacteria (26.3 +/- 7.1%), Proteobacteria (26.2 +/- 6.6%), and Bacteroidetes (9.4 +/- 2.4%). Key members of the dog ocular surface microbiome, found in all dogs and corresponding to >25% of all identified OTUs (operational taxonomic units), were part of the Bifidobacteriaceae, Lachnospiraceae, Moraxellaceae, Corynebacteriaceae families. Genera previously thought to account for the majority of the core ocular surface microbiome in the dog (Staphylococcus sp., Streptococcus sp., and Bacillus sp.) were associated with only 2.63% of overall reads. Conclusions This study shows the feasibility of conjunctival swabs and high-throughput sequencing to profile the bacterial community structure of the canine ocular surface. A core ocular surface microbiome was identified for this canine population.
Objective To perform detailed analysis of retinal changes in dogs with SARDS using optical coherence tomography (OCT), funduscopy, and molecular analysis. Animals Subjects were 29 dogs from 12 US states and Canada diagnosed with SARDS by 8 ophthalmologists. An additional 7 eyes from 5 deceased SARDS dogs were used for molecular and histological analysis. Procedures Dogs were evaluated using chromatic pupil light reflex testing (cPLR), and electroretinography (ERG); subjects underwent complete ophthalmic examination, including funduscopy, retinal photography, and OCT, in addition to complete laboratory analysis, blood pressure evaluation, abdominal and thoracic radiographs, and computerized tomography (CT) imaging to assess possible systemic abnormalities. Histology and immunohistochemistry analysis was performed in 2 SARDS eyes. Microarray analysis was performed in 5 SARDS retinas. Results Thirty-eight percent of patients had <1-mm wide retinal detachments (RD) on OCT analysis, which could not be detected by funduscopy or retinal photographs. Systemic hypertension did not seem to be a contributing factor (RD 22.2%; ND 20%, Odds ratio = 1.1). No dogs showed neoplastic changes by thoracic or abdominal radiography, or CT imaging. There was no statistically significant difference in age (RD 7.9 +/- 1.9 years (mean +/- SD); ND 7.6 +/- 1.7 years, p = 0.69) or duration of blindness prior to presentation (RD 18 +/- 7 days (mean +/- SD); ND 21 +/- 12 days, p = 0.28). Microarray and histology analysis of SARDS eyes revealed molecular changes suggestive of immune-mediated damage. Conclusions Observed histological, molecular, and OCT changes are highly suggestive of immune-mediated damage in SARDS eyes.
OBJECTIVETo evaluate the retina and optic nerve head (ONH) in canine eyes predisposed to glaucoma using optical coherence tomography (OCT).ANIMALSTwenty-five eyes (24 dogs).METHODSMeasures of peripapillary retinal, retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) thickness and ONH parameters were obtained in vivo by OCT of the unaffected eye in dogs diagnosed with unilateral primary glaucoma (predisposed; n = 12) and compared with measures of healthy control eyes (normal; n = 13). Repeatability and intrarater reliability were explored using intraclass correlation coefficients (ICC).RESULTSCompared to normal eyes, predisposed eyes had a thinner retina in the temporal (P = 0.005), inferior quadrants (P = 0.003), and decreased inner retinal thickness (superior: P = 0.003, temporal: P = 0.001, inferior: P < 0.001, nasal: P = 0.001). Predisposed eyes had a thinner RNFL compared to normal eyes (P = 0.005), and when analyzed in quadrants, it was thinner in the superior (P < 0.001), temporal (P = 0.034), and nasal quadrants (P = 0.001). Repeatability (ICC 0.763-0.835) and intrarater reliability (ICC 0.824-0.942) were good to excellent for measures of retinal thickness and adequate for RNFL measurements (ICC 0.701-0.798). Reliable measurements of optic disk area were obtained and were similar between groups (P = 0.597). Measurements of parameters relying on automated software detection (GCC, optic cup, optic rim) had inadequate repeatability and reliability.CONCLUSIONStatistically significant differences in retinal and RNFL thicknesses were identified in normal and predisposed eyes. Reliable and consistent measurements of variables with manual adjustment of software detected parameters were obtained. Validation of OCT as a diagnostic tool for clinical assessment in canine glaucoma is warranted.
OBJECTIVETo describe clinical characteristics, bacterial isolates, and in vitro antimicrobial susceptibility patterns for cats with bacterial keratitis.ANIMALS STUDIEDEighty one cats with bacterial keratitis.PROCEDURESMedical records of cats with a clinical diagnosis of bacterial keratitis, confirmed by corneal culture, were reviewed from June 2004 to July 2017. Animal signalment, bacterial isolates, aerobic bacteria in vitro antimicrobial susceptibility test results, and pertinent clinical features were recorded. Percentages of susceptible aerobic bacterial isolates were statistically compared among selected antimicrobials.RESULTSThere were 102 aerobic bacterial isolates recovered from corneal samples of the 81 cats presented with bacterial keratitis. The most frequent bacteria isolated were Staphylococcus species, which constituted 55% (56/102) of total isolates. All aerobic bacterial isolates grouped together had the highest percentage of susceptibility to ofloxacin (100%), ciprofloxacin (94%), chloramphenicol (93%), doxycycline (92%), ticarcillin (90%), gentamicin (89%), moxifloxacin (89%), tobramycin (86%), neomycin (85%), amikacin (84%), and cefazolin (84%). The same isolates had the lowest percentage of susceptibility to polymyxin B (2%), bacitracin (15%), and clindamycin (31%). When analyzed separately, the isolated Staphylococcus species had the highest percentage of susceptibility to ofloxacin (100%), tobramycin (93%), and neomycin (85%) and the lowest percentage of susceptibility to polymyxin B (3%) and bacitracin (13%).CONCLUSIONSMembers of the Staphylococcus genus were the most frequent bacteria isolated from cases of feline bacterial keratitis. On the basis of in vitro susceptibility testing and mechanism of action, ofloxacin, ciprofloxacin, ticarcillin, gentamicin, or moxifloxacin are recommended for initial antimicrobial therapy of suspected bacterial keratitis in cats.
To evaluate tissue levels, safety, and efficacy of topical ophthalmic 0.5% and 1% pirfenidone in decreasing subconjunctival fibrosis. Twelve normal beagle dogs PROCEDURES: A 5 × 1 mm diameter silicone disk was implanted subconjunctivally in one eye, and then dogs were treated with topical 0.5% pirfenidone (n = 9) in artificial tears or artificial tears alone (n = 3) for 28 days. To evaluate tissue drug levels, a single sample of tears, conjunctiva, and aqueous humor was collected 30 (n = 3), 90 (n = 3), and 180 min (n = 3) following administration of the last drop of pirfenidone, respectively. Fibrous capsule thickness and staining for Ki67 and fibroblast activation protein alpha (FAPα) were evaluated histologically. After a 2-week washout, the experiment was repeated in the opposite eye and using 1% pirfenidone. Treatment with pirfenidone resulted in thinner fibrous capsules and decreased staining for FAPα with no adverse effects. The implant in one dog treated with pirfenidone extruded. There was no difference in tissue levels, capsular thickness, or staining for Ki67 or FAPα between dogs treated with 0.5% or 1% pirfenidone. Pirfenidone may decrease fibrosis following glaucoma shunt surgery and can potentially be used indefinitely due to minimal side effects.
The aim of the study was to determine the lacrimal fluid (LF) contents of glucose, urea nitrogen, and creatinine in cats. A total of 96 cats were included in the study. Venous blood and LF samples were collected. For LF sampling, three small polyurethane sponges were placed in the ventral fornix of both eyes. Both LF and plasma concentrations of glucose, urea nitrogen, and creatinine were quantitatively analyzed and compared. Glucose (n = 40) and urea nitrogen concentrations (n = 42) measured in LF from both eyes highly correlated. While there was a very strong correlation (ρ = 0.97) between urea nitrogen concentrations in blood plasma and the corresponding tear levels (with the median LF urea nitrogen being 109% of that measured in plasma), the LF glucose concentrations were significantly lower than the corresponding plasma concentrations (with only 13% of the blood glucose concentration detected in the LF). The creatinine concentrations in tears were much lower than those in plasma, and LF creatinine was detectable in only 12/48 cats (25%). Hence, a comparison of the LF creatinine concentrations between both eyes or with the corresponding plasma creatinine concentration was not possible. Measurement of LF urea nitrogen concentrations in cats appears to be reliable and might have potential clinical utility. Measurement of LF glucose concentrations is less reliable but may still be useful in some cats. Creatinine is not reliably detected in the LF in cats. Further studies determining clinical utility of LF metabolites in cats and other companion animals are warranted.
To investigate age-associated changes of flash visual evoked potentials (FVEPs) in sedated horses. Twenty-eight clinically healthy Standardbred Warmblooded trotters, aged 36 hours to 28 years. Light-adapted FVEPs and FERGs were recorded (An-vision RETIport, Roland-consult, Germany) in response to flash stimuli. Sedation was obtained using alpha-2-agonists intravenously. Akinesia of the eyelids was induced and pupils were dilated. Reproducible FVEPs and FERGs were readily recorded from all foals and horses. The FVEP waveform included up to four positive components (P1-P5) and two negative components (N1 and N2) and FVEP waveform morphology was similar across all age groups. Some differences in peak times and amplitudes associated with increasing age were observed. FVEP amplitudes recorded from newborn foals were well above the amplitudes observed in normal adult horses and FVEP peak times were somewhat shorter. In adult horses, a significant increase in P4 peak time and a gradual decrease in amplitudes, mainly for N2P4, were seen across the life-span. The overall equine FVEP waveform was similar across the normal life-span of the horse in our cross-sectional study. We found that the visual system of the foal seems to be well developed already at birth. Furthermore, our results showed a decrease in amplitudes and increase in some peak times with increasing age. We recommend that age-matched controls should be used when evaluating foals and young horses in clinical practice, whereas horses over the age of three years can be compared to other adult horses.
To screen a closed herd of the Old Kladruber Horses (OKH) for the prevalence of ocular disorders and report normal ocular variations. Two hundred and sixty-one horses, 122 Old Kladruber Gray Horses, and 139 Old Kladruber Black Horses owned by the National Stud Farm Kladruby nad Labem, Czech Republic, were included in the study with signalment and pedigree information recorded. Bilateral ocular examination of manually restrained horses was performed in a darkened environment by a single examiner (RA), using a portable slit-lamp biomicroscope, direct ophthalmoscope, and monocular indirect ophthalmoscopy using a Finnoff transilluminator and 20 D condensing lens. Fluorescein testing was performed when indicated. The animal ages ranged from 3 months to 27 years (mean 7.82 years, median 6 years). The gender ratio (males:females) was 109:152. Ophthalmological abnormalities were found in 133 (50.96%) horses; with right and left eyes affected equally. The most common abnormalities were cataract formation (35 horses), iris hyperpigmentation (29 horses), alterations in corpora nigra size (26 horses), nonsenile vitreal degeneration (24 horses), linear keratopathy (11 horses), corneal stromal haze (nine horses) and corneal subepithelial punctate opacities (nine horses). The most frequent variations of normal ocular anatomy were posterior lenticular suture lines (222 horses), tapetal hypoplasia (95 horses) resulting in a multi-colored tapetal fundus (31 horses), nuclear sclerosis (48 horses), and senile vitreal degeneration (30 horses). Ocular disorders were relatively common in OKH, but typically not vision threatening and not interfering with the quality of life.
The purpose of this study was to report the preliminary results of a novel micropulse transscleral diode laser cyclophotocoagulation (MP-TSCP) as primary therapy for glaucomatous dogs. Client owned dogs undergoing MP-TSCP therapy at a veterinary referral center. Retrospective study of dogs with glaucoma that were treated with MP-TSCP with a minimum of 1 month (range: 1-18 months) of follow-up. Reported outcomes were intraocular pressure (IOP), treatment parameters, reduction in medications, complications, and incidence of repeat therapy. Thirty dogs (35 eyes) were evaluated. The mean age was 9.0 years. Mean preoperative IOP was 34.5 mm Hg. Mean postoperative IOP at 1 month (35/35 eyes) was 22 mm Hg, 2 months (26/35 eyes) was 20.5 mm Hg, 4 months (20/35 eyes) was 19 mm Hg, 6 months (10/35 eyes) was 19 mm Hg, 12 months (8/35 eyes) was 21 mm Hg. First treatment success rate was 19/35 eyes (54.3%). Repeat laser was performed in 11 eyes with 4/11 eyes responding favorably for a total IOP control of 23/35 eyes (65.7%). Mean energy levels employed were 137.5 seconds and 2351 mW at 31.3% duty cycle. Reduction in medications was from a mean of 3.6 medications preoperatively to 3.1 medications postoperatively. Complications included corneal ulcers 5/35 eyes (14.3%), uncontrolled IOP in 12/35 eyes (34.3%) and repeat treatment in 11/35 eyes (31.4%). MP-TSCP was successful in controlling IOP in most patients as well as to reduce postoperative medications with minimal resultant intraocular inflammation and complications. The micropulse procedure also can be repeated. Future investigations to study effective treatment parameters are warranted in a larger series of patients over a longer period of evaluation.
To assess the efficacy of an endothelial keratoplasty procedure at defined intervals to 1 year postoperatively for the treatment of corneal endothelial dystrophy (CED) in a canine patient. A dog diagnosed with CED with progressive corneal edema underwent an endothelial keratoplasty. The patient was examined pre- and postoperatively with slit lamp biomicroscopy and ultrasonic pachymetry. Mean central corneal thickness (CCT) measured with pachymetry was >1400 μm preoperatively and decreased postoperatively to 725 μm. The transplanted donor tissue became transparent 2 weeks postoperatively and incorporated with the recipient cornea. The graft remained transparent throughout the duration of the postoperative period evaluated in this study (2 weeks postoperatively to 1 year). The canine patient was comfortable pre- and postoperatively. Endothelial keratoplasty is a potential therapeutic option for canine cases with progressive corneal thickening due to CED. As this is a single case study, further investigation into the use of endothelial keratoplasty to treat CED is warranted. Moreover, canine patients with CED might serve as a surgical model for human patients with Fuchs' Endothelial Corneal Dystrophy.
The aim of this study was to describe normal ocular morphology and establish parameters for select diagnostics in a population of Panamanian Golden Frogs (PGF) Atelopus zeteki maintained at the Detroit Zoo. A total of 22 toads free of ocular disease were included in this study. Ophthalmic diagnostic tests included as follows: endodontic absorbent paper point tear test (EAPPTT), assessment of intraocular pressures (IOP), Rose Bengal stain, palpebral fissure width, blink rate and corneal cultures. Histology was performed on stored postmortem samples. Panamanian Golden Frogs have a distinct brow ridge and mobile third eyelid. Biomicroscopy revealed avascular, convex corneas with a shallow anterior chamber. Iris color ranged from yellow to green with dark pigmentation of the peripheral iris. Pupil shape was round. Posterior segment and fundus could not be visualized. Total number of blinks observed over a 10-minute period was one. Mean EAPPTT was 2 ± 1 mm and 3 ± 1 mm in males and females, respectively (P). Mean IOP using rebound tonometry in horizontal and vertical restraint positions were 21.6 ± 2.28 mm Hg and 17.45 ± 3.66 mm Hg, 21.85 ± 2.7 mm Hg and 17.5 ± 3.93 mm Hg in males and females, respectively. Mean palpebral fissure width was 5.02 ± 0.46 mm and 6.12 ± 0.39 mm in males and females, respectively (P). Enterococcus faecalis was isolated from one clinically normal toad. Tear production and blink rate were low and not significantly different between males and females. Intraocular pressure was significantly greater in male toads (P value <0.01). Females had a significantly larger palpebral fissure width when compared to males (P value <0.01) 5819. The ophthalmic parameters established in this study can aid in the evaluation and diagnosis of eye diseases in PGF.
To describe the clinical signs, management, histopathologic findings, and outcome of three dogs with a corneocentric presentation of nodular granulomatous episcleritis (NGE). Three dogs of varying breeds were presented for a unilateral, nonpainful, and infiltrative corneal lesion in the dorsal aspect of the eye. Clinical response to symptomatic topical treatment directed at a presumed inflammatory or immune-mediated cause was poor. Due to this, and concerns of neoplasia, ultrasonography (n = 1), incisional biopsy (n = 2), and/or enucleation (n = 2) were performed. The inflammatory infiltrate observed on histopathology was identical to that seen in nodular granulomatous episcleritis in all three cases. However, atypically the inflammation was confined to the cornea and limbus, without episcleral or conjunctival involvement. Inflammation of the cornea was full thickness to Descemet's membrane. Following enucleation (n = 2), there were no postoperative complications, and no reported ophthalmic disease in the remaining eye. Currently, the single non-enucleated case remains controlled with systemic and topical immunosuppression. To the best of the authors' knowledge, this is the first report of an NGE condition purely affecting the full thickness of the cornea, without episcleral or conjunctival involvement. The authors propose this to represent an atypical corneocentric variant of NGE. This clinical presentation can resemble neoplasia; incisional biopsy is recommended for a definitive diagnosis. Further research into the optimal treatment strategies for this variant of NGE is required.
A yearling Thoroughbred stallion and an 8-year-old Saddlebred mare were evaluated for persistent mucoid ocular discharge. Examination of both horses revealed copious yellow-tan mucoid ocular discharge with a negative Jones I test, absent nasal punctum, and unsuccessful anterograde nasolacrimal duct (NLD) irrigation. Clinical abnormalities were present on the right side only in one horse and bilaterally in the other. Computed tomography (CT) with contrast confirmed nasolacrimal duct atresia in both horses. Under general anesthesia, the affected NLD was catheterized anterograde and contrast injected. Using fluoroscopic guidance, retrograde access to the distal NLD was obtained for through-and-through wire access. Over the wire, the stoma was dilated and a temporary stent placed for 4-8 weeks. After the procedure, both horses were comfortable and free of ocular discharge at the minimum time of last follow-up, 9 months postoperatively. Fluoroscopically guided neocanalization is a viable alternative to traditional surgical approaches for NLD atresia, especially when access to the site of obstruction is limited.
(a) To evaluate the epidemiology of equine eosinophilic keratoconjunctivitis (EK) in the western United States, (b) to ascertain the efficacy of keratectomy and diamond burr debridement vs medical management alone, (c) to determine the efficacy of various medical therapies, and (d) to further characterize the histopathologic findings of the disease in horses. Twenty-nine horses (47 eyes) diagnosed with EK from 1993 to 2017. Retrospective medical record review; owner questionnaire. Average age of presentation was 11 ± 4 years. Warmbloods were significantly overrepresented (P = 0.024). Twenty horses were treated with medical therapy alone, five were treated with superficial lamellar keratectomy, and four were treated with diamond burr debridement. Follow-up data were available for 38 eyes of 23 horses. Median time to resolution for horses treated with either superficial keratectomy or diamond burr debridement (62 days) was not statistically significantly different from those that underwent medical therapy alone (46 days; P = 0.33). Eyes treated with topical steroids had a statistically significant longer median time to resolution (61 days) compared to those that did not receive topical steroid (44 days; P = 0.023). Common histopathologic findings in keratectomy samples included the presence of eosinophils, vascularization, and an eosinophilic membrane spanning areas of ulceration. In this population, time to EK resolution was similar for horses treated with medical and surgical management. The use of topical steroids was associated with a prolonged time to resolution. Keratectomy samples from horses with EK had similar findings to those reported in other species.
To evaluate microbiological, histological, and ultrastructural characteristics of short-term cryopreserved (STC) equine corneoscleral tissue (7 years). Thirty-four healthy equine globes. After a decontamination protocol, globes were enucleated and stored at -20°C in broad-spectrum antibiotics. Corneoscleral tissue was evaluated at different storage periods: 1 month-1 year (20 eyes) and 7-9 years (12 eyes). Two eyes were used as controls. Microbiologic study included direct (blood, McConkey, and Sabouraud agars) and enrichment (brain-heart infusion broth) cultures. Cryopreservation artifacts were evaluated by hematoxylin-eosin. Corneoscleral collagen organization and number of normal and dead keratocytes were established by transmission electron microscopy. All microbiologic direct cultures were negative. Enrichment cultures were positive in 12.5% of corneal and 59.4% of scleral tissues (p = 0.136; p = 1.000). Cryopreservation artifacts were most commonly observed in LTC tissues (P = 0.002). Normal keratocytes were predominant in STC corneas (STC 60% and LTC 0%) and apoptotic ones in LTC (STC 40% and LTC 90%), whereas necrotic keratocytes were only seen in LTC (LTC 10%) (P = 0.001). No structural differences were detected in collagen organization between STC and LTC (p = 1.000; p = 0.703). Cryopreservation of equine corneoscleral tissue did not yield direct bacterial contamination. Apoptosis is the main cause of death of cryopreserved equine keratocytes. Based on the lack of significant structural differences between STC and LTC samples, these cryopreserved tissues could potentially be used for tectonic support for at least 9 years without structural or microbiological impediment.