Veterinary ophthalmology最新文献

Objective: To further investigate quantitative and qualitative tear-film dynamics through tear-film osmolarity, meibometry, meibography, and non-invasive tear-film break-up time and to describe a survey of parameters in normal eyes of healthy non-brachycephalic dogs.

Animals studied: Thirty-two veterinary hospital staff and student owned dogs between 1 and 7 years with no known comorbidities or ocular disease.

Procedure: Complete ophthalmic examination, tear-film osmolarity (I-PEN® VET), meibometry (Meibometer MB560), meibography, and non-invasive tear-film break-up time (handheld Ocular Surface Analyzer) were performed. Significance threshold was 0.05. Q-Q plots and histograms were used to assess normality of measurements. Data were summarized descriptively with mean, standard deviation, median, and interquartile range (IQR). Pearson and Spearman's correlations were used to test for correlations between diagnostics with each other and tear-film break-up times.

Results: Thirty-two dogs (64 eyes) met the inclusion criteria. Mean tear-film osmolarity level was 293.6 ± 14.1 mOsm/L (IQR 282.5-302.3). Median meibomian lipid level was 30.4 Meibometry Units (MU) (IQR 11.5-59.1). Median percent loss of meibomian glands in the upper eyelids was 25.3% (IQR 13.5-26.8). Median percent loss of meibomian glands in the lower eyelids was 26.0% (IQR 13.5-52.3). Automatic assessment of meibomian gland loss showed that grade 0 was present in 4/128 (3.1%) eyelids, grade 1 in 78/128 (60.9%) eyelids, grade 2 in 30/128 (23.4%) eyelids, and grade 3 in 16/128 (12.5%) eyelids.

Conclusions: Tear-film osmolarity, meibometry, meibography, and non-invasive tear break-up time can easily be incorporated into routine ophthalmic examinations to provide clinical information about meibomian gland morphology and function.

Objectives: This study aimed to explore anatomical differences in the aqueous humor (AH) outflow pathway between male and female dogs using ultrasound biomicroscopy (UBM).

Animals studied: Clinical data were collected from 30 eyes of 30 dogs (15 males: 10 right eyes, 5 left eyes; and 15 females: 7 right eyes, 8 left eyes) treated at the Veterinary Medical Teaching Hospital of Chungbuk National University, South Korea, between August 2018 and February 2024.

Procedure: The study conducted an in-depth UBM examination, specifically observing peripheral anterior chamber depth (ACD), geometric iridocorneal angle (ICA), and angle-opening distance (AOD) alongside measurements of ciliary cleft width (CCW), length (CCL), and area (CCA), and assessed the longitudinal fibers of ciliary muscle thickness (Lf-CMT) and the longitudinal and radial fibers of ciliary muscle thickness (LRf-CMT) for sex-based differences.

Results: The study identified a significant sex difference in peripheral ACD, with females displaying shallower depths compared to males, potentially clarifying the higher incidence of glaucoma in female dogs. No significant sex differences were found in ICA, AOD, CC parameters, or ciliary muscle parameters measurements.

Conclusion: This research uncovered that peripheral ACD is significantly shallower in females than in males, potentially indicating a risk factor that could contribute to the development of primary angle-closure glaucoma.

Objective: To investigate the impact of dexamethasone on the antibiotic susceptibility of common ocular pathogens in dogs and identify safe antibiotic-steroid combinations for veterinary ophthalmology.

Methods: This study utilized 30 bacterial isolates of Staphylococcus pseudintermedius, Streptococcus canis, and Pseudomonas aeruginosa, collected from canine patients with suspected bacterial keratitis. The isolates were tested against 17 antibiotics in the presence of dexamethasone concentrations ranging from 0 to 2 mg/mL. Minimum inhibitory concentrations (MICs) were determined using standardized broth microdilution techniques, and changes in susceptibility were analyzed statistically.

Results: Dexamethasone administration resulted in a significant increase in resistance for ciprofloxacin, ticarcillin, tobramycin, and ceftiofur in S. pseudintermedius; ticarcillin in S. canis; and ciprofloxacin and moxifloxacin in P. aeruginosa. Despite these increases, amikacin and cefazolin showed minimal impact on resistance when combined with dexamethasone, indicating their potential for safe use in combination therapies.

Conclusion: The findings highlight the potential for dexamethasone to alter antibiotic susceptibility in canine ocular pathogens. While dexamethasone can increase resistance in certain antibiotics, amikacin and cefazolin appear to be safer options for combination therapy.

Purpose: To describe the findings of computed tomography (CT) used to investigate signs of ophthalmic disease in pet rabbits.

Methods: Retrospective review of records of patients with signs of ophthalmic disease that underwent CT scans in three referral centers between 2001 and 2022. Signalment, presenting ophthalmic and nonophthalmic complaints, CT findings, and restrain modality were recorded.

Results: There were 85 rabbits representing 14 breeds including 28/85 (32.9%) crossbreed/unknown and 25/85 (29.4%) Dwarf rabbits. The top presenting ophthalmic complaints were ocular discharge (48/85, 56.5%), exophthalmos (34/85, 40%), and epiphora (14/85, 16.5%), while 38/85 (44.7%) rabbits also had nonophthalmic complaints. Anesthetic complications forced 1/85 (1.18%) CTs to be stopped. There were ophthalmic abnormalities in the remaining 81/84 (96.4%) CTs with exophthalmos and/or nasolacrimal duct disease affecting 76/81 (93.8%) rabbits and 68/81 (84%) also showing nonophthalmic abnormalities. Ophthalmic abnormalities were seen with nonophthalmic disease in 64/81 (79%) rabbits with dental disease being the most common (52/64, 81.3%) although only 20/52 (38.5%) had presented with dental complaints. No association was found between the presence of exophthalmos and/or NLD disease and dental disease. There were no obvious image artifacts in the 4/84 (4.8%) physically restrained patients.

Conclusion: Examination with CT in the present study mainly supported the investigation of ocular discharge, exophthalmos, and epiphora, and of possible local and systemic involvement in one eye with intraocular neoplasia. Adnexal disease was often seen with previously unknown, nonophthalmic pathology, which warrants prospective, controlled studies. Image quality studies in a large number of physically restrained patients are also warranted.

Objectives: To assess if an affordable, commercially available 275 nm ultraviolet C (UV-C) device can inhibit fungal pathogens associated with equine keratomycosis and to establish the optimal exposure time/dose required in vitro.

Methods: Fungal inhibition zone surface areas of isolates from two fungal genera (Aspergillus and Fusarium spp.) were compared in triplicates after UV-C exposure at distances of 10, 15, and 20 mm with single or repeat doses (4 h apart) of 5, 10, 15, or 30 s duration after 24, 48, and 72 h of incubation. Inhibition zones were microscopically assessed, and regrowth checks were performed.

Results: Fungal inhibition was achieved with the lowest exposures/doses of 5 s/7.5 mJ/cm² and 10 s/7 mJ/cm² at distances of 10 and 20 mm, respectively. At 10 mm, the fungal inhibition zone was statistically significantly enlarged by increasing exposure/dose from 5 s to 15 s/22.5 mJ/cm² for all isolates. Only Aspergillus flavus showed a further significant zone enlargement after a 30 s/45 mJ/cm² exposure/dose. Fungal inhibition zone sizes did not differ significantly between isolates after 15 s exposure regardless of distance, but an increased distance led to a subjective increase in fungal regrowth. While inhibition zones decreased over time, no central growth was noted despite the lack of complete fungal eradication.

Conclusions: For Aspergillus and Fusarium spp., an exposure/dose of 15 s at a 10 mm distance/22.5 mJ/cm² may optimally align antifungal efficacy with previously reported corneal safety data. Further preclinical and safety studies are required to ensure that this effect translates into clinical practice.

Objectives: To assess the agreement between intraocular pressure (IOP) measurements in rats using different animal-adapted tonometers and to evaluate the relation among the devices.

Methods: IOP was measured using the TonoLab tonometer, followed by the TonoVet Plus and finally, the Tono-Pen AVIA Vet. A total of 24 eyes were studied from 12 healthy Wistar rats anesthetized with sevoflurane. Agreement analysis was performed between the TonoLab tonometer and the TonoVet Plus, and the TonoLab and Tono-Pen AVIA Vet using the intraclass correlation coefficient (ICC). For the tested pairs, Bland-Altman graphs were also performed. The relation of TonoVet Plus and Tono-Pen AVIA Vet tonometers to TonoLab was also evaluated using a simple linear regression.

Results: The agreement between the TonoLab tonometers and the TonoVet Plus was weak (ICC = 0.173, 95% CI [-0.129; 0.489], p = 0.130) and not statistically significant. The agreement between the TonoLab and the Tono-Pen AVIA Vet tonometers was negligible (ICC = 0.011, 95% CI [-0.117; 0.218], p = 0.448). Linear regression analysis between the TonoLab and the TonoVet Plus (p = 0.256), as well as between the TonoLab and the Tono-Pen AVIA Vet (p = 0.897), was not statistically significant.

Conclusions: The measurements revealed a consistent pattern in which the Tono-Pen AVIA Vet showed the highest mean IOP values, followed by the TonoVet Plus and the TonoLab. Knowing the normal values of indirect IOP in rats for each of these tonometers, as well as the differences between them, is fundamental for the proper interpretation of the measurements obtained and for allowing reliable comparisons between the devices.

Objective: To evaluate the effects of latanoprostene bunod on intraocular pressure (IOP) and pupil diameter (PD) in normal cats and cats with feline congenital glaucoma (FCG).

Animals studied: Five normal and 5 FCG cats.

Procedures: This masked, controlled crossover study comprised a 1-day Pre-treatment phase followed by two 10-day Treatment phases, each followed by a 10-day Recovery phase. During treatment, all cats received twice daily 0.005% latanoprost (LAT) or 0.024% latanoprostene bunod (LBN) in a randomized eye. Following Recovery, the same eye was treated with the opposite drug. Contralateral eyes served as saline-treated controls. Intraocular pressure and PD measurements were performed three times daily during all study phases. Data were analyzed via constrained longitudinal data analysis models.

Results: Neither drug significantly reduced IOP in normal cats. In FCG cats, statistically significant reductions in mean (95% CI) IOP were observed relative to controls 4 h after LAT and LBN treatment (-5.5 mmHg [-8.4, -2.5], p < .001, -7.2 mmHg [-10.2, -4.3], p < .001, respectively). These differences represented 28.4% and 37.9% IOP reductions, respectively. Mean IOP reduction after 4 h was significantly greater with LBN treatment compared to LAT (-1.8 mmHg [-3.2, -0.4], p = .012). However, these IOP reductions were not considered clinically significant. Both drugs similarly reduced PD in normal and FCG cats.

Conclusions: Transient IOP reduction was observed after topical administration of LAT and LBN in FCG cats; and mean IOP difference was statistically significantly greater in LBN-treated eyes. However, the apparent enhanced hypotensive effect of LBN is not clinically significant.

Objectives: To assess the impact of thrice-daily instillation of 0.4% ketorolac trometamol (KT) over 15 days on blood count, serum biochemistry, and urinalysis in healthy cats. Additionally, we tested the efficacy of luminol to detect fecal occult blood (FOB) in feces.

Methods: A placebo-controlled, randomized study was conducted with 24 healthy cats. In 12 cats, each eye received either 40 μL of KT or saline (S) every 8 h for 15 days. An additional 12 cats received saline in both eyes and served as controls (S). Baseline blood count, serum biochemical analysis, urinalysis, and FOB testing were performed before the study and after each 15-day treatment period.

Results: Baseline blood count, serum biochemistry, and urinary values were within reference limits for both treatments. By day 15, increased cholesterol (p = 0.002) and decreased potassium (p = 0.01) levels were observed in KT. Despite these changes, all measurements remained within reference limits, except for ALT, which significantly increased at day 15 in KT when compared to baseline (p = 0.01) and S (p = 0.003). At baseline, all fecal samples from KT and S tested negative for FOB. By day 15, 10 of 12 KT samples tested positive for FOB (p < 0.0001).

Conclusion: This study demonstrates that thrice-daily instillation of KT for 15 days induces a subclinical hepatocellular injury and gastrointestinal bleeding, with potential effects on potassium levels in healthy cats. Luminol proved to be a reliable test for detecting fecal occult blood in the feces of healthy cats.

Objective: To present a consistent and reproducible method for measuring ocular structures and to establish reference ranges for ocular biometry in the adult domestic guinea pig (Cavia porcellus) without clinical or imaging evidence of ophthalmic disease, using a 64-slice multidetector computed tomography (CT) scanner.

Procedure: This retrospective, observational anatomical study analyzed 60 eyes from 30 guinea pigs with no history of or clinical or imaging signs of ocular disease. Head CT scans were used to measure globe length, width, and height via 3D multiplanar reconstruction. Additional measurements included lens width and length, anteroposterior lengths of the anterior and vitreous chambers, and attenuation values of the lens and vitreous. These parameters were evaluated in relation to age, sex, and weight.

Results: Reference values were established, with globe width being the greatest dimension (11.25 ± 1.61 mm), followed by height (10.56 ± 1.43 mm) and length (10.49 ± 1.44 mm). Increased body weight correlated significantly with greater length of the anterior chamber (p = 0.045). Older age was significantly associated with increased lens width (p = 0.044). Intra-observer reliability was excellent and interobserver reliability was good to excellent.

Conclusions: Computed tomography is a reliable tool for assessing ocular biometry in guinea pigs. The established reference values can aid in detecting ocular conditions that alter globe dimensions in guinea pigs over 18 months of age.

Purpose: Corneal sequestrum is a condition commonly observed in cats, though the pathogenesis is not fully understood. The occurrence of conjunctival sequestrum has not previously been documented. This report aims to describe a series of cases of conjunctival sequestra in cats.

Animals and animal samples studied: A 3-year-old male Persian cat presented after 2 months of blepharospasm and epiphora in the right eye, accompanied by mild conjunctival hyperemia. Histopathologic findings from four other cases are also included.

Methods: After presentation of Patient 1, the database (from 2007 to 2025) of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) was searched for other cases of feline conjunctival sequestrum, four of which were identified. In all cases, an amorphous black plaque was observed in the conjunctival tissue during the ophthalmological examination. Three of the four cases also had corneal sequestra ipsilaterally. Histopathology of the corneal sequestra was available in two of the cases.

Results: Histopathology of all five conjunctival lesions revealed focally extensive compaction and brunescence of proprial collagen and absence of fibroblasts. Three of the cases had conjunctival ulceration overlying the sequestrum. The surrounding substantia propria was variably infiltrated by inflammatory cells and microorganisms. The appearance of conjunctival sequestra was remarkably similar to that of corneal sequestra.

Conclusion and clinical relevance: This is the first reported case-series of feline conjunctival sequestrum. Variable presentation of concurrent ocular abnormalities and history led to no definitive conclusion to a common cause. Similar to corneal sequestra, chronic irritation and a possible contribution from FHV-1 infection are suspected.