Marginal resection and infracyanine green-mediated photodynamic therapy in the management of feline eyelid squamous cell carcinoma: Two cases.

OBJECTIVE: Describe the presenting features, surgical procedure, and clinical outcomes of two cats managed with marginal resection and photodynamic therapy (PDT) for eyelid squamous cell carcinoma (SCC). ANIMALS STUDIED: A 12-year-old female spayed domestic shorthair cat (case 1) and a 10-year-old female spayed domestic shorthair cat (case 2). PROCEDURES: Following marginal resection of the eyelid neoplasm, hemostasis was achieved using a handheld cautery unit then 1 mL of infracyanine green was injected into the surgical wound bed. Photodynamic therapy was performed using an 810 nm diode laser in two consecutive steps: (i) six cycles at 500 mW for 30 s per cycle, using a rapid movement; then (ii) one (case 1) or two cycles (case 2) of 30 s at 2000 mW, using a slow deliberate movement to effect (charred surface). RESULTS: Histopathology was consistent with SCC resected with incomplete margins in both cats. Follow-up duration was 416 and 161 days in case 1 and case 2, respectively. Consecutive exams and photo-documentation (in clinic or by owners) showed appropriate healing of the lower eyelid, with a smooth lid margin, and no evidence of tumor regrowth or ocular irritation. Subtle trichiasis was noted in case 1 on day 185, but not at the last follow-up. CONCLUSIONS AND CLINICAL RELEVANCE: Marginal resection followed by PDT may be a valid alternative to complete surgical resection of periocular SCC in cats. The procedure was easy to perform, post-operative recovery was uncomplicated, and neither cat developed recurrent disease during the follow-up period.

Schirmer tear test-1 with open or closed eyelids: An evaluation in brachycephalic and nonbrachycephalic dogs.

PURPOSE: Assess aqueous tear production when measured with the dogs' eyelids open or closed. METHODS: Thirty healthy dogs (15 Shih Tzus, 15 Labrador retrievers) were recruited. With the order of testing randomized for each dog, two sessions (separated by 30 min) of STT-1 testing were performed with the dogs' eyelids closed or open. Schirmer strip wetness (every 10 s for 60 s) and number of time(s) the strip dislodged during testing were recorded in each eye. Preferred STT-1 method was surveyed via a global Listserv of the veterinary ophthalmology community. RESULTS: STT-1 values were significantly higher in closed versus open eyes in Shih Tzus (18.6 ± 2.7 mm/min vs. 16.3 ± 2.5 mm/min; p = .002) and Labrador retrievers (21.6 ± 2.9 mm/min vs. 17.8 ± 3.2 mm/min, p < .001), findings that were also significant at times <60 s for either breed (p ≤ .004). Schirmer strips dislodged from six dogs with open eyelids and no dogs with closed eyelids. Maximal STT-1 difference with closed versus open eyelids was 13 mm/min in Labrador retrievers and 7 mm/min in Shih Tzus. Survey results from 275 veterinarians showed STT-1 performed with "closed eyelids" (38.5%), "open eyelids" (26.9%), or "never paid attention, sometimes closed, sometimes open" (34.6%). CONCLUSIONS: Eyelids status (closed or open) during STT-1 testing had a significant impact on aqueous tear secretion in brachycephalic and nonbrachycephalic dogs, highlighting the importance of consistency when repeating STT-1 in a canine patient. STT-1 differences are likely due to sustained reflex tearing throughout the test duration when the dogs' eyelids are closed.

The effect of systemic acetazolamide administration on intraocular pressure in healthy horses-A preliminary study.

OBJECTIVES: In equine glaucoma, topical treatment with carbonic anhydrase inhibitors (CAIs) is recommended. Oral acetazolamide, a systemic CAI, is used in horses with hyperkalemic periodic paralysis. Information regarding its effect on equine intraocular pressure (IOP) is scarce. The aim of the study was to determine the effect of oral acetazolamide treatment on IOP in horses, in a case-control study. ANIMALS: Ten healthy horses. PROCEDURES: Horses were treated with oral acetazolamide (4.4 mg/kg) BID for 1 week. Serum acetazolamide concentrations were determined by liquid chromatography/tandem mass spectrometry, and IOP were measured before treatment, daily during treatment, and at 48 and 72 h after treatment. RESULTS: Acetazolamide serum levels reached steady state at 72 h after the first oral dose. In a mixed effect model logistic regression, there was a significant decrease in IOP on the third treatment day, of 2.4 mmHg (p = .012) and 2.7 mmHg (p = .006) in the left (OS) and right eye (OD), respectively. On the seventh day, there was a decrease in 2.5 mmHg (p = .008) and 2.7 mmHg (p = .007) OS and OD, respectively. A significant increase occurred 48 h following treatment discontinuation (3.6 mmHg, p < .001 and 3.5 mmHg, p < .001 OS and OD, respectively). The area under the concentration versus time curve (AUC(0-10h)) was 1.1 ± 0.5 µg/mL*h, mean residence time 6.7 ± 4.3 h, peak plasma concentration (Cmax) 0.4 ± 0.4 µg/mL and time to reach Cmax 1.8 h. There was a significant increase in serum concentrations 1, 2, 48, 72, and 156 h following the first drug administration (p < .05). CONCLUSIONS: Further studies are required to determine whether acetazolamide is a potential treatment for equine glaucoma.

The 100 most-cited articles published in the Veterinary Ophthalmology journal between 1998 and 2022: A bibliometric study.

PURPOSE: The aim of this study was to bibliometrically analyze the 100 most-cited articles published in the Veterinary Ophthalmology (VO) journal. METHODS: Web of Science was searched for citations of VO articles published in 1998-2022. Tissue and species studied, and first and last author domicile and affiliation were recorded for the 100 most-cited articles and descriptively analyzed. RESULTS: Altogether, the 100 most-cited VO articles have cited a total of 5483 times. Most commonly, these were devoted to the cornea (23%), multiple tissues (19%), and glaucoma (16%). Studies on dogs (36%), horses (17%), and multiple species (15%) were most often cited. Most first/last authors were from the USA (n = 113), Brazil (n = 13), and France and Germany (n = 7 each), and most frequently affiliated with the University of Florida (n = 36), University of Wisconsin-Madison (n = 15), and Animal Health Trust, North Carolina State University, and Ohio State University (n = 6 each). KN Gelatt (n = 9), DE Brooks (n = 6), and FJ Ollivier and EO MacKay (n = 5 each) were the most frequent first or last authors. The greatest number of citations was for articles with KN Gelatt (n = 555), FJ Ollivier (n = 411), and DE Brooks (n = 372) as first or last authors. "The comparative morphology of the tapetum lucidum" by FJ Ollivier et al. (2002) is the most frequently cited article in VO history (n = 178). CONCLUSIONS: This study provides insight into the impact of publishing in VO and a more comprehensive understanding of trends and the most influential contributions to VO.

A retinoscopic survey of donkeys and goats.

PURPOSE: Assess the refractive states of donkeys and goats. METHODS: Forty-two donkeys and 28 goats were enrolled. The mean ± SD ages were 7.68 ± 7.33 years for donkeys and 4.26 ± 2.33 years for goats. Seven donkeys and one goat were <6 months old. Retinoscopy was performed in alert animals, following cycloplegia in goats but not in donkeys. Normality was determined using the Kolmogorov-Smirnov test. The two primary meridians and two eyes were compared using Pearson's correlation and paired Student's t-tests. The association between refractive states and age was examined using one-way ANOVA in donkeys and a paired Student's t-test in goats. One-sample t-tests were conducted to assess if the refractive error distributions were significantly different from "0". RESULTS: The mean ± SD spherical equivalent (SE) refractive errors of the right and left donkey eyes were -0.80 ± 1.03 D and -0.35 ± 0.95 D, respectively. The majority (86%) of the donkeys had an astigmatic refraction and eight (19%) had anisometropia. The mean SE refractive errors of the right and left goat eyes were -0.15 ± 1.1 D and -0.18 ± 1.2 D, respectively. The majority (54%) of the goat eyes had an astigmatic refraction and five (18%) had anisometropia. The right and left eye SE refractive errors were positively correlated in both species (both p = .9). Age was not correlated with refractive error in both donkeys (p = .09) and goats (p = .6). CONCLUSIONS: Both goats and donkeys are emmetropic.

Effect of anesthetic induction with propofol, alfaxalone or ketamine on intraocular pressure in cats: a randomized masked clinical investigation.

OBJECTIVE: To compare the effect of propofol, alfaxalone and ketamine on intraocular pressure (IOP) in cats. STUDY DESIGN: Prospective, masked, randomized clinical trial. ANIMALS: A total of 43 ophthalmologically normal cats scheduled to undergo general anesthesia for various procedures. METHODS: Following baseline IOP measurements using applanation tonometry, anesthesia was induced with propofol (n = 15), alfaxalone (n = 14) or ketamine (n = 14) administered intravenously to effect. Then, midazolam (0.3 mg kg-1) was administered intravenously and endotracheal intubation was performed without application of topical anesthesia. The IOP was measured following each intervention. Data was analyzed using one-way anova and repeated-measures mixed design with post hoc analysis. A p-value <0.05 was considered significant. RESULTS: Mean ± standard error IOP at baseline was not different among groups (propofol, 18 ± 0.6; alfaxalone, 18 ± 0.7; ketamine, 17 ± 0.5 mmHg). Following induction of anesthesia, IOP increased significantly compared with baseline in the propofol (20 ± 0.7 mmHg), but not in the alfaxalone (19 ± 0.8 mmHg) or ketamine (16 ± 0.7 mmHg) groups. Midazolam administration resulted in significant decrease from the previous measurement in the alfaxalone group (16 ± 0.7 mmHg), but not in the propofol group (19 ± 0.7 mmHg) or the ketamine (16 ± 0.8 mmHg) group. A further decrease was measured after intubation in the alfaxalone group (15 ± 0.9 mmHg). CONCLUSIONS AND CLINICAL RELEVANCE: Propofol should be used with caution in cats predisposed to perforation or glaucoma, as any increase in IOP should be avoided.

Treatment with chloroquine is retinotoxic in captive African penguins (Speniscus demersus). Attenuation and recovery of electroretinographic responses.

PURPOSE: To evaluate the effect of prophylactic anti-malarial chloroquine treatment, and its cessation, on electroretinographic (ERG) responses of captive African penguins. METHODS: A brief ERG protocol ("QuickRetCheck") was recorded under mesopic conditions with manual restraint and no sedation or pupil dilation. Birds were recorded on two separate occasions, first while being treated with a daily chloroquine dose of 10 mg/kg for 12 days (n = 15, treatment group) and second after 4 months without chloroquine treatment (n = 6, off-treatment group). Three birds were recorded on both occasions. Three other birds from the flock that died were studied histopathologically. RESULTS: Scotopic responses were unmeasurable in either recording and therefore were not analyzed. Mean a- and b-wave amplitudes of the mixed rod-cone responses to standard (3 cd·s/m2 ) and high (10 cd·s/m2 ) intensity flashes were higher in the off-treatment group. No difference in implicit times was observed. Sex, age, and number of previous chloroquine treatments did not affect ERG responses. Histopathology revealed Plasmodium spp.in the lungs, liver, and brain, but not in the eyes, of the necropsied birds, and there were no signs of retinitis or retinopathy. CONCLUSIONS: Daily chloroquine treatment was associated with attenuated ERG responses in penguins, which improve following cessation of treatment. Further work is warranted to establish a chloroquine dose that is efficacious yet has minimal adverse effects. Our results suggest that ERG responses of captive penguins undergoing ERG for any indication (such as prior to cataract surgery), must be evaluated in light of the birds' anti-malaria treatment status.

Does the order of intraocular pressure measurement affect tonometry results?

PURPOSE: To determine whether the order of intraocular pressure (IOP) measurement affects readings, regardless of which eye is measured first. METHODS: Intraocular pressure was measured in 31 and 41 dogs using applanation and rebound tonometry, respectively. Initially, IOP was measured in the first (randomly chosen) eye (reading A), followed by measurement in the fellow eye (reading B), and a third (repeated) measurement in the first eye (reading C). After 15 minutes, measurements were repeated in reverse order (readings D - F). RESULTS: Applanation tonometry revealed significant differences between readings A & B (15.6 ± 2.3 and 14.8 ± 2.7 mm Hg, respectively, p = .02), A & C (15.6 ± 2.3 and 14.5 ± 2.4 mm Hg, respectively, p = .002), D & E (14.5 ± 2.3 and 13.7 ± 2.1 mm Hg, respectively, p = .02), D & F (14.5 ± 2.3 and 13.9 ± 1.9 mm Hg, respectively, p = .05), and A & E (15.6 ± 2.3 and 13.7 ± 2.1 mm Hg, respectively, p = .001). Rebound tonometry yielded similar results, with additional differences between B & C (19.1 ± 3.0 and 18.2 ± 2.4 mm Hg, respectively, p = .002) and E & F (18.7 ± 3.3 and 18.2 ± 3.3 mm Hg, respectively, p = .02). CONCLUSIONS: Intraocular pressure measured in the first eye, whether right or left, is higher than in the fellow eye. Repeated tonometry in the same visit could result in a significant IOP decrease, though the magnitude may not be clinically appreciable.

Is it necessary to wait several minutes between applications of different topical ophthalmic solutions? A preliminary study with tropicamide eye drops in healthy dogs.

OBJECTIVE: To evaluate the efficacy of topical tropicamide when placed at different time intervals before or after a saline drop. ANIMALS STUDIED: Eight healthy Labrador and golden retriever dogs. PROCEDURES: The effect of 1% tropicamide on pupillary diameter (PD) was measured over 240 min when administered alone (control) and then 1 and 5 min prior to, or following, application of a saline drop, with 1-week washout between each of the five trials. Data were analyzed using repeated-measures ANOVA and Tukey post hoc test. RESULTS: Only 6/110 pairwise comparisons among the 5 trials were statistically significant (p ≤ .035), with post-hoc analysis showing no significant differences (p ≥ .14) between the overall means of all trials. In all five trials, maximal PD was reached 30 min after tropicamide application and maintained until 210 min for 180 min (p = .0005). CONCLUSIONS: Our results suggest that waiting 1 min between applications of different ophthalmic solutions may be sufficient for maximal drug effect. Care should be taken when extrapolating these results to other species and different ophthalmic formulations.

Ocular anatomy and correlation with histopathologic findings in two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) diagnosed with inflammatory phakitis and retinitis.

PURPOSE: Review octopus ocular anatomy and describe the histopathologic findings in three octopuses diagnosed with phakitis and retinitis. ANIMALS: Two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) with a history of ophthalmic disease. METHODS: A literature search was performed for the ocular anatomy section. Both eyes from all three octopuses, and two control eyes, were submitted for histopathologic evaluation. Hematoxylin and eosin stain was used for standard histopathologic evaluation; GMS stain was used to screen for fungi, gram stain for bacteria; and Fite's acid fast stain for acid fast bacteria. RESULTS: Anatomically, the anterior chamber of the octopus has direct contact with ambient water due to an opening in the dorsal aspect of a pseudocornea. The octopus lens is divided into anterior and posterior segments. The anterior half is exposed to the environment through the opening into the anterior chamber. Neither part of the lens has a lens capsule. The retina is everted, unlike the inverted vertebrate retina, and consists of just two layers. Histopathology revealed inflammatory phakitis and retinitis of varying severity in all six eyes of the study animals. No intraocular infectious organisms were recognized but one common octopus eye had clusters of coccidian parasites, identified as Aggregata sp., in extraocular tissues and blood vessels. CONCLUSION: We describe inflammatory phakitis and retinitis in two species of octopuses. The underlying cause for the severe intraocular response may be direct intraocular infection, water quality, an ocular manifestation of a systemic disease, or natural senescence.

Prognostic indicators and outcome in dogs undergoing temporary tarsorrhaphy following traumatic proptosis.

PURPOSE: Retrospectively evaluate prognostic indicators and outcome in dogs undergoing temporary tarsorrhaphy following traumatic proptosis. METHODS: Medical records (2004-2017) were reviewed for signalment, cause and duration of proptosis, and clinical findings on admission. The operating faculty member, post-operative medications, and ophthalmic findings at last recheck were recorded. Owners of dogs with blinded eyes were surveyed regarding final outcome and satisfaction. Data were analyzed using Fisher's exact, Likelihood ratio, and Mann-Whitney tests. RESULTS: At last recheck, 17.5 ± 7.3 (mean ± SD) days post-operatively, vision was present in 12/43 eyes (28%). Vision at last recheck was not correlated with breed, cause or duration of proptosis, or post-operative medications (P > .05), but was correlated with presence of direct and indirect pupillary light reflexes (PLRs) on admission (P = .001 and .02, respectively), and with assessment and surgery performed by veterinary ophthalmologists rather than surgery or emergency personnel (P = .015). Mean satisfaction scores (graded 0-10) of 22 owners contacted 59.6 ± 48.2 months after last recheck were 7.8 ± 2.6 (n = 6), 5.7 ± 4.9 (n = 3), and 8.8 ± 1.3 (n = 13) for dogs with phthisical eyes, eyes requiring long-term medications, and blind but otherwise normal eyes, respectively (P = .284). CONCLUSIONS: Contrary to previous studies, breed, and cause and duration of proptosis, did not significantly affect outcome. Testing of direct and indirect PLR is a simple and significant prognostic indicator. Patients assessed and operated by a veterinary ophthalmologist have better prognosis.

Using a smartphone-based digital fundus camera for screening of retinal and optic nerve diseases in veterinary medicine: A preliminary investigation.

BACKGROUND: Ophthalmoscopy is a valuable tool in clinical practice. We report the use of a novel smartphone-based handheld device for visualisation and photo-documentation of the ocular fundus in veterinary medicine. METHODS: Selected veterinary patients of a referral ophthalmology service were included if one or both eyes had clear ocular media, allowing for examination of the fundus. Following pharmacological mydriasis, fundic images were obtained with a handheld fundus camera (Volk VistaView). For comparison, the fundus of a subset of animals was also imaged with a veterinary-specific fundus camera (Optomed Smartscope VET2). RESULTS: The large field of view achieved by the Volk VistaView allowed for rapid and thorough observation of the ocular fundus in animals, providing a tool to visualise and record common pathologies of the posterior segment. Captured fundic images were sometimes overexposed, with the tapetal fundus artificially appearing hyperreflective when using the Volk VistaView camera, a finding that was less frequent when activating a 'veterinary mode' that reduced the sensitivity of the camera's sensor. The Volk VistaView compared well with the Optomed Smartscope VET2. LIMITATION: The main study limitation was the small sample size. CONCLUSIONS: The Volk VistaView camera was easy to use and provided good-quality fundic images in veterinary patients with healthy or diseased eyes, offering a wide field of view that was ideal for screening purposes.

Role of Inflammation in Canine Primary Glaucoma.

Primary glaucoma is a painful, progressive, and blinding disease reported in many canine breeds, characterized by intraocular pressure (IOP) elevation in the absence of antecedent intraocular disease. Clinical observations of dogs with primary glaucoma suggest that many affected eyes develop concurrent intraocular inflammation in addition to elevated IOP. In this work, we summarize the current knowledge that relates inflammation to primary glaucoma in dogs, reviewing studies focused on genetics, physiology, histopathology, bioanalysis of ocular fluids, therapeutics, and clinical outcomes of glaucomatous patients. Through disruption of the blood-aqueous and blood-retinal barriers, pigment dispersion, and biochemical changes to the aqueous humor and tear film, the pathogenesis of canine primary glaucoma appears to involve inflammatory changes to various extents and with various consequences from the front to the back of the eye. Among others, inflammation further impacts IOP by reducing aqueous humor outflow at the level of the iridocorneal angle and accelerates vision loss by promoting neuronal degeneration. As such, the vicious cycle of ocular inflammation and IOP elevation might warrant the use of anti-inflammatory medications as a core component of the treatment regime for dogs with primary glaucoma, either therapeutically (i.e., actively glaucomatous eye) or prophylactically in the yet unaffected contralateral eye.

Mucoadhesive Polymers Enhance Ocular Drug Delivery: Proof of Concept Study with 0.5% Tropicamide in Dogs.

Purpose: To assess the efficacy of 0.5% tropicamide applied after topical administration of 1.4% hydroxyethyl cellulose (HEC) or 1.2% hyaluronic acid (HA) at different time intervals. Methods: Eleven healthy Labrador retriever dogs were used. The study consisted of 7 trials in which pupil diameter (PD) was measured every 30 min for 7 h after drug administration. In trial 1, PD was measured after tropicamide application (control). In trials 2-7, PD was measured after treatment with tropicamide 10 s, 1 and 5 min after application of HEC or HA. Data were analyzed using analysis of variance and post hoc Holm-Sidak tests. Results: Maximal PD (mean ± standard deviation) was significantly greater (P < 0.001) in 5 of 6 experimental trials, with the greatest PD recorded when HEC was applied 1 min (12.2 ± 0.4 mm) and HA 10 s (12.3 ± 0.5 mm) before tropicamide, compared with 11.2 ± 0. 7 mm in control trial 1. PD >10 mm was maintained for 2.75-5 h in trials 2-7 and 2.25 h in trial 1 (P < 0.001). Area under the PD-time curve ranged from 61.9 to 71.3 ± 2.9 mm·hours in trials 2-7, significantly greater than 59.3 ± 1.8 mm·hours in control trial 1 (P ≤ 0.031). Conclusions: Tropicamide efficacy was enhanced by prior administration of a mucoadhesive polymer. Additional studies are needed to determine if HEC and HA of varying concentrations similarly extend and potentiate the effect of other topical ophthalmic drugs in canine eyes.

Seroprevalence of Leptospira spp. in Horses in Israel.

Leptospirosis has been reported in both humans and animals in Israel but has not been reported in horses. In 2018, an outbreak of Leptospira spp. serogroup Pomona was reported in humans and cattle in Israel. In horses, leptospirosis may cause equine recurrent uveitis (ERU). This report describes the first identification of Leptospira serogroup Pomona as the probable cause of ERU in horses in Israel, followed by an epidemiological investigation of equine exposure in the area. Serologic exposure to Leptospira was determined by microscopic agglutination test (MAT) using eight serovars. In 2017, serovar Pomona was identified in a mare with signs of ERU. Seven of thirteen horses from that farm were seropositive for serogroup Pomona, of which three had signs of ERU. During the same time period, 14/70 horses from three other farms were positive for serogroup Pomona. In 2015, two years prior to this diagnosis, 259 horses from 21 farms were sampled and one horse tested seropositive for serovar Icterohaemorrhagiae. In 2018, one year later, 337 horses were sampled on 29 farms, with none testing seropositive. Although horses are not considered a major host of Leptospira spp., it appears that horses may be infected, and clinically affected, in the course of an outbreak in other species. The identification of leptospirosis in stabled horses may impose a significant zoonotic risk to people.

Naturally-occurring myopia and loss of cone function in a sheep model of achromatopsia.

Achromatopsia is an inherited retinal disease characterized by loss of cone photoreceptor function. Day blind CNGA3 mutant Improved Awassi sheep provide a large animal model for achromatopsia. This study measured refractive error and axial length parameters of the eye in this model and evaluated chromatic pupillary light reflex (cPLR) testing as a potential screening test for loss of cone function. Twenty-one CNGA3 mutant, Improved Awassi, 12 control Afec-Assaf and 12 control breed-matched wild-type (WT) Awassi sheep were examined using streak retinoscopy and B-mode ocular ultrasonography. Four CNGA3 mutant and four Afec-Assaf control sheep underwent cPLR testing. Statistical tests showed that day-blind sheep are significantly more myopic than both Afec-Assaf and WT Awassi controls. Day-blind sheep had significantly longer vitreous axial length compared to WT Awassi (1.43 ± 0.13 and 1.23 ± 0.06 cm, respectively, p < 0.0002) and no response to bright red light compared to both controls. Lack of response to bright red light is consistent with cone dysfunction, demonstrating that cPLR can be used to diagnose day blindness in sheep. Day-blind sheep were found to exhibit myopia and increased vitreous chamber depth, providing a naturally occurring large animal model of myopia.