Veterinary ophthalmology最新文献

Purpose: To determine whether the differences in intraocular pressure (IOP) change after the topical application of 0.5% tropicamide and 0.5% phenylephrine (TP) are due to anatomical variations in the anterior chamber using ultrasound biomicroscopy (UBM).

Methods: Prospective clinical data from 27 eyes of 14 dogs with normal eye conditions were analyzed. IOP and UBM measurements were taken before and 30 min after administering a topical TP. Dogs were categorized into two groups based on an IOP increase criterion of 4 mmHg: the high group and the stable group. Parameters measured included the iridocorneal angle (ICA), angle-opening distance (AOD), ciliary cleft width (CCW), length (CCL), area (CCA), ciliary body axial length (CBAXL), and ciliary process-sclera angle (CPSA).

Results: Both groups showed a statistically significant decrease in ICA and an increase in AOD. However, in the stable group, CPSA increased, CBAXL decreased, and CCA increased, whereas in the high group, CPSA and CBAXL did not change significantly, and CCA decreased.

Conclusion: In the stable group, although the pupil dilated, the ciliary body relaxed, leading to an increase in the CCA. Conversely, in the high group, the pupil dilated, and the ciliary body remained unrelaxed, resulting in a reduction in the CCA. These iridociliary changes with pupil dilation increase the risk of elevated IOP. Therefore, an increase in IOP following TP administration may serve as a prognostic indicator for possible glaucoma risk.

Objective: To carry out a descriptive investigation of the most relevant morphological features of the harpy eagle eye and to provide normative data for selected ophthalmic diagnostic tests.

Animals studied: Twenty-nine clinically normal harpy eagles (Harpia harpyja).

Procedures: Selected morphological ocular observations were made in live animals under physical restraint: Schirmer tear test (STT), culture of normal conjunctival flora, slit lamp biomicroscopic examination of adnexa and anterior segment, rebound tonometry, applanation tonometry, central corneal thickness (CCT), palpebral fissure length (PFL), B-mode ultrasound, and ocular biometry. Eyelid histology was evaluated from previously deceased individuals.

Results: STT type I 17.48 ± 5.476 mm/min; Rebound tonometry 14.00 IQR 4.00 mmHg; Applanation tonometry 15.00 IQR 6.00 mmHg; CCT 0.563 ± 0.041 mm; PFL 26.42 ± 2.13 mm; Axial globe length 29.43 IQR 0.42 mm; Anterior chamber depth 5.00 IQR 0.22 mm; Axial length of the lens 6.60 IQR 0.97 mm; Vitreous chamber depth 16.50 IQR 0.80 mm, and pecten length 8.80 IQR 1.47 mm. The conjunctiva of the lower eyelid has a distinct cartilaginous plate adjacent to the conjunctival epithelium. The most frequent conjunctival bacterial isolates were E. coli (32.76%) followed by Enterobacter spp. (15.52%) and Streptococcus spp. (10.34%).

Conclusion: Reference data and morphologic observations obtained in this investigation might aid in the understanding and diagnosis of eye diseases in harpy eagles and improve the clinical management of ocular disease.

Objective: To evaluate the impact of two excipients, 1.4% polyvinyl alcohol (PVA) and 0.75% cross-linked hyaluronic acid (XHA), on tear film concentrations of cefazolin and chloramphenicol.

Animals studied: Ten ophthalmologically healthy dogs.

Procedures: Cefazolin and chloramphenicol were compounded into 5.5% and 0.5% solutions, respectively, using either 1.4% PVA or 0.75% XHA. In the first trial, each dog received cefazolin-PVA in one randomly assigned eye and cefazolin-XHA in the contralateral eye. One month later, the experiment was repeated using chloramphenicol formulations. Tear fluid was sampled at 0, 1, 5, 10, 15, 30, 60, 120, 240, 360, and 480 min following eyedrop administration using 2 μL capillary tubes. Tear concentrations of cefazolin and chloramphenicol were measured using UV-Vis spectrophotometry.

Results: Tear film concentrations of cefazolin and chloramphenicol were significantly higher with XHA compared to PVA at all time points (p ≤ 0.020), except for baseline (both antibiotics), times 1 min, 60 min, and 120 min for cefazolin. The tear film kinetics exhibited a biphasic pattern, with drug levels decreasing from 0 to 120 min, then slightly increasing between 120 and 360 min before declining again until 480 min. The area under the time-concentration curve (AUC_0-480) was significantly greater with XHA versus PVA formulations (p = 0.002), with a median 2.4 and 4.2 times higher for cefazolin and chloramphenicol, respectively.

Conclusion: The cross-linked hyaluronic acid significantly enhanced the retention and overall exposure of both cefazolin and chloramphenicol in the canine tear film. These findings suggest that XHA could serve as a superior delivery vehicle for ocular antibiotics, potentially improving treatment outcomes for ophthalmic infections.

A 15-year-old Swiss Warmblood gelding was presented to the ophthalmology service of Zurich University due to severe visual impairment. Ophthalmic and neurologic examinations were performed, raising suspicion of post-retinal blindness. Standing contrast computed tomography (CT) of the head revealed a partially calcified, soft tissue attenuating mass in the sphenopalatine sinus with concurrent compression of the optic nerves and chiasm. Differential diagnosis included neoplasia and granulomatous disease. The horse was euthanized, and the head was subsequently examined by magnetic resonance imaging (MRI) followed by gross and histopathology. MRI showed compression of the optic nerves and chiasm. Histopathology revealed the formation of fibrous granulation tissue, osseous metaplasia, and pyogranulomatous inflammation in the sphenopalatine sinus. Periodic acid-Schiff reaction and Grocott silver staining demonstrated branching septated filament hyphae and fungal spores. The optic nerves and chiasm were evident of mild neuronal atrophy, showing mild gliosis, vacuolation, and mild lympho-plasmacytic inflammation. Mycotic sphenopalatine sinusitis should be considered as a more specific diagnosis for post-retinal blindness in horses due to the compression of the optic nerve(s) and chiasm.

Objective: To evaluate the levels of trace elements in the tear film of healthy dogs.

Animals studied: Twenty-five healthy Labrador retrievers.

Procedures: Tear samples were collected from the ventral conjunctival fornix of each dog using a Schirmer tear test strip. Elemental analysis was conducted using the particle-induced X-ray emission (PIXE) method with a 1.7 MV Pelletron accelerator. Trace element levels were compared across all dogs using the Kruskal-Wallis test with post hoc Tukey analysis and between male and female dogs using the Mann-Whitney test.

Results: The study included 14 neutered males and 11 spayed females, with a mean (±SD) age of 19.8 ± 3.1 months (range 14.3-26.5, median 18.8 months). Elemental analysis of tear samples revealed the presence of calcium (Ca), chloride (Cl), iron (Fe), phosphorus (P), potassium (K), sodium (Na), and sulfur (S). The median ± SEM peak area levels were highest for Cl (69 530 ± 1432) and K (5782 ± 514), followed by S (3545 ± 772), Na (3387 ± 159), P (1408 ± 160), Ca (593 ± 85), and Fe (276 ± 206). Compared to males, female dogs had significantly higher peak areas for S (2272 ± 549 vs. 4389 ± 1484, p = 0.037) and Ca (536 ± 76 vs. 800 ± 148, p = 0.029).

Conclusions: This study provides a detailed assessment of the trace element composition in the tear film of healthy dogs. These findings enhance our understanding of canine ocular surface physiology and may have potential implications for the diagnosis and management of ocular surface diseases in dogs.

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.

Objective: To describe the clinical and morphological features of a case of superficial nodular keratitis in a dog.

Case description: A German shepherd dog previously diagnosed with chronic superficial keratitis (CSK) presented with a nonpainful, unilateral corneal nodule. After a complete ophthalmic examination, topical treatment with dexamethasone (0.1% dexamethason, WZW) was prescribed. However, the patient did not respond to this treatment; thus, a superficial keratectomy was performed. The lesion was examined histologically and immunohistochemically.

Results: The ophthalmic examination revealed a round, pink, solid nodule, approximately 0.5 cm in diameter, located in the ventral, paracentral cornea. Results from the Schirmer tear test I, tonometry, and fluorescein staining were in the normal ranges. A small amount of mucous discharge and moderate hyperemia of the bulbar conjunctiva were present. The histological examination revealed a solid mass in the superficial corneal stroma under the corneal epithelium. Hematoxylin and eosin (HE) staining showed that the mass was supplied with blood vessels; HE and immunohistochemistry revealed it consisted of a mixture of plasma cells (MUM⁺ cells), B lymphocytes (CD79⁺, CD20⁺ cells), T lymphocytes (CD3⁺), and macrophages (Iba1⁺ cells). Mitotic figures were absent. Some nuclei in inflammatory infiltrates displayed a Ki76⁺ reaction. Inflammatory infiltrates were present in the superficial stroma and the corneal epithelium.

Conclusion: These novel results demonstrate that the features of nodular keratitis in a German shepherd dog previously diagnosed with CSK differ from the features of xanthogranulomas, nodular episcleritis, corneal granulomas, pyogranulomatous keratitis, corneal epithelial inclusion cysts, protozoal keratitis, and corneal squamous cell carcinoma.

Objective: This retrospective study evaluates the efficacy of povidone-iodine (PI) and polyhexamethylene biguanide (PHMB) as preoperative antiseptics in equine ophthalmic procedures.

Animals studied: Horses that underwent routine ophthalmic surgery and procedures.

Procedures: Data were collected retrospectively from the medical records of equine patients undergoing ophthalmic procedures. Inclusion criteria were sampling for aerobic microbial culture at three different time points (T0: pre-irrigation, T1: post-irrigation, and T2: postoperatively) and T0 showing bacterial growth. Microbiological outcomes were assessed semi-quantitatively by creating a scoring system to describe the bacterial load. Furthermore, the species detected were evaluated. Poisson regression analysis was performed to evaluate the efficacy of the disinfectants.

Results: Eighty eyes (75 horses) met the inclusion criteria, with 36 cases being aseptically prepared with PI and 44 with PHMB. Both antiseptics significantly reduced the bacterial load and number of bacterial species (p < .001) between time points T0 and T1, and T0 and T2. PHMB showed a reduction in the bacterial load by 64% (CI: 51%-73%) whereas PI reduced it by 48% (CI: 36%-58%) between time points T0 and T1. The reduction in the number of bacterial species between time points T0 to T1 was significantly greater in the PHMB group (85%, CI: 70%-93%), compared to PI (47%, CI: 26%-62%).

Conclusion: Both PHMB and PI reduced the bacterial load and number of species on the ocular surface and eyelids significantly, with 0.1% PHMB being superior to 0.2% PI. Therefore, PHMB can be considered as a good alternative in preoperative antisepsis in equine ophthalmic procedures.

Objective: To evaluate the efficacy of 2% dorzolamide ophthalmic solution for reduction of postoperative ocular hypertension (POH) following routine phacoemulsification surgery in dogs.

Animals studied: Thirty one dogs (53 eyes) with naturally occurring cataracts undergoing routine phacoemulsification surgery.

Procedure(s): A prospective, double-masked, randomized, placebo-controlled study design was utilized. Dogs received 2% dorzolamide ophthalmic solution or saline 1 h prior to surgery then three times daily for 21 days postoperatively in the operated eye(s). Intraocular pressure (IOP) was recorded 1 h prior to surgery and 3 h, 7 h, 22 h, 1 week and 3 weeks postoperatively. Statistical analyses were performed using chi-squared and Mann-Whitney U test with a significance level of p < .05.

Results: Postoperative ocular hypertension (IOP ≥25 mmHg, <24 h after surgery) occurred in 28/53 (52.8%) eyes. There was significant reduction in the incidence of POH for eyes receiving dorzolamide (10/26 (38.4%) eyes) versus eyes receiving placebo (18/27 (66.7%) eyes) (p = .0384). Animals were followed for a median of 163 days after surgery. Thirty-seven (37/53 (69.8%)) eyes were visual at final examination and 3/53 (5.7%) globes were enucleated postoperatively. At last follow-up, there was no difference in visual status (p = .9280), need for topical IOP lowering medication (p = .8319) or incidence of glaucoma (p = .5880) based on treatment group.

Conclusions: Perioperative administration of topical 2% dorzolamide reduced the incidence of POH after phacoemulsification in the dogs studied. However, this was not associated with differences in visual outcome, incidence of glaucoma or need for IOP-lowering medications.