Purpose: To retrospectively evaluate and describe the relationship between the use of topical corticosteroids and the development of crystalline corneal opacities (steroid keratopathy) in a colony of research Beagles and Beagle-derived dogs. Methods: Medical records of 73 purpose-bred Beagles and Beagle-derived dogs were reviewed from June 2012 to May 2021. All dogs were treated with topical ophthalmic corticosteroids for at least 21 days. In addition to regular ophthalmic examination, some dogs also had a systemic lipid profile (n = 6) performed to work up further and characterize the crystalline corneal opacities. Globes of 3 dogs were examined histopathologically. Results: Axial stromal crystalline corneal opacities were appreciated in 25 eyes of 14 dogs after a median of 141 days after initiating treatment (35–396 days). Multiple corticosteroids were used, including neomycin-polymyxin b-dexamethasone 0.1% ophthalmic ointment, prednisolone acetate 1% ophthalmic suspension, and difluprednate 0.05% ophthalmic emulsion (Durezol). Resolution of corneal opacity was documented in 4 of 25 eyes when ophthalmic corticosteroids were discontinued after a median of 406.5 days (271–416 days). Histopathologic examination revealed a dense band of acellular material, poorly staining with periodic acid–Schiff, subtending the corneal epithelium, and being surrounded by spindle cells. Conclusions: This case series documents the onset of steroid keratopathy in Beagles and Beagle-derived dogs after treatment with ophthalmic corticosteroids. Clinical resolution of steroid keratopathy lesions may be possible after discontinuation of ophthalmic corticosteroids.

Background: Inherited primary open-angle glaucoma (POAG) in Beagle dogs is a well-established large animal model of glaucoma and is caused by a G661R missense mutation in the ADAMTS10 gene. Using this model, the study describes early clinical disease markers for canine glaucoma. Methods: Spectral-domain optical coherence tomography (SD-OCT) was used to assess nine adult, ADAMTS10-mutant (median age 45.6 months, range 28.8–52.8 months; mean diurnal intraocular pressure (IOP): 29.9 +/− SEM 0.44 mmHg) and three related age-matched control Beagles (mean diurnal IOP: 18.0 +/− SEM 0.53 mmHg). Results: Of all the optic nerve head (ONH) parameters evaluated, the loss of myelin peak height in the horizontal plane was most significant (from 154 +/− SEM 38.4 μm to 9.3 +/− SEM 22.1 μm; p < 0.01). There was a strong significant negative correlation between myelin peak height and IOP (Spearman correlation: −0.78; p < 0.003). There were no significant differences in the thickness of any retinal layers evaluated. Conclusions: SD-OCT is a useful tool to detect early glaucomatous damage to the ONH in dogs before vision loss. Loss in myelin peak height without inner retinal thinning was identified as an early clinical disease marker. This suggests that initial degenerative changes are mostly due to the loss of myelin.

Despite increased recognition of caudal vertebral anomalies in the domestic dog (Canis lupus familiaris), studies describing tail deformities remain limited. To address this gap in the literature, this study aimed to identify and classify the caudal vertebral anomaly phenotypes in a pedigree of Beagles. Subjects included 67 dogs (36 males and 31 females), aged eight months to eight years old (M= 38.8 ± 25.6 months). All 67 dogs were visually examined, and tails were palpated to determine if they had any kinks, bends, misalignments, or deformities in their tail prior to radiographic assessment. Radiographs of the caudal vertebrae were obtained from 53 dogs and evaluated for congenital anomalies, including block vertebrae, hemivertebrae, brachyury (very short tail), and axial deviations. Of the 53 radiographed dogs, 25 (47.2%) exhibited at least one congenital caudal vertebral anomaly, with block vertebrae being the most common finding (43.4%). Four dogs (7.6%) had mild congenital abnormalities detected radiographically that were not identified during physical examination. Based on pedigree structure, an autosomal recessive trait is suspected. These findings demonstrate a high prevalence of caudal vertebral anomalies within this pedigree of Beagles and emphasize the importance of radiographic evaluation for accurate identification and phenotypic classification.