Objective To investigate the variance in corneal epithelial thickness (CET) and limbal epithelial thickness (LET) according to the age and skull type by using spectral‐domain optical coherence tomography (SD‐OCT) in normal dogs. Animals and procedures This study used an eye each from 46 dogs (24 brachycephalic and 22 non‐brachycephalic dogs) assessed to have clear corneas. Each dog was classified according to age into groups 1 (0–5 years), 2 (6–10 years), and 3 (>11 years). OCT imaging was performed on the central cornea for CET and perpendicular to the quadrant of the limbus for LET. The average of the maximum LET (maxLET) value was measured in four eye quadrants. Results Corneal epithelial thickness was not significantly different according to age in brachycephalic and non‐brachycephalic dogs. Visualization of the limbal invagination was better when the maxLET was thick. Nasal and temporal maxLETs were significantly thicker than superior and inferior maxLETs in non‐brachycephalic dogs. In brachycephalic dogs, there was a significant decrease in nasal maxLET with age (rs = −0.489, p = .015). Significant differences between brachycephalic and non‐brachycephalic dogs were observed in nasal maxLET (p = .024) and temporal maxLET (p = .011). Conclusions Invagination was better visualized in the nasal and temporal limbal quadrants of non‐brachycephalic dogs compared with brachycephalic dogs, and the maxLETs of the regions were thicker than those of the brachycephalic dogs. CET and LET measurements using SD‐OCT can help in clinical assessment and research on ocular surface diseases in dogs.

This study was aimed to evaluate the prophylactic anti-glaucoma effect of topical 5% betaxolol (BTX) and 2% dorzolamide (DRZ) on the second eye in dogs with unilateral primary angle closure glaucoma (PACG). Medical records of 60 dogs with unilateral PACG who received prophylactic anti-glaucoma eyedrops in the second eye, from 2016 to 2021, were reviewed. The duration of prophylactic effects of BTX only and DRZ after BTX failure was calculated. The prophylactic effects of BTX were maintained on 28/60 (46.7%) eyes until last visit and BTX failure was observed on median 510 (range, 53-1,927) days in 32/60 (53.3%) eyes. After DRZ instillation in BTX failure eyes, the prophylactic effects were extended at median 610 (range, 157-2,270) days in 21/32 (65.6%) eyes. DRZ failure eyes (17/21, 81.0%) eyes required chemical ablation or surgical intervention due to uncontrolled intraocular pressure. The duration of prophylactic effects was decreased with aging (R² = 0.334, p = 0.006). The predominant breeds were Shih-Tzu (41.9%) and American Cocker Spaniel (30.6%) with no significant differences in survival curves (p = 0.210). The average prophylactic effects of BTX persisted more than 1.5 year and could be selected the first prophylactic eye drop in unilateral PACG. Also, early surgical intervention should be considered in prophylactic medications failure cases.

A 9-year-old spayed female Shih-Tzu was presented with a mass on the upper eyelid of the right eye (OD). The eyelid mass continued to enlarge along the eyelid margin and the eyelid skin. Throughout the follow-up examinations, the mass did not affect the palpebral conjunctiva OD. Until 9 months since the mass was first identified, the dog did not show any clinical signs related to the mass. However, after 11 months, the owner complained of the dog's discomfort on OD and decided on surgical excision of the mass. There were no abnormalities in the complete blood count and serum chemistry profiles. The pentagonal resection was performed to completely remove the mass in the eyelid. There were no suspicious findings of metastasis on whole-body computed tomography scan immediately before the surgery. On histopathology and immunohistochemistry for multiple myeloma oncogene-1, the eyelid mass was diagnosed as extramedullary plasmacytoma (EMP). Surgical margin of the mass was clearly cut. No recurrence was observed during the 5-month follow-up. EMPs on the eyelid have rarely been reported in dogs. Although EMP is a benign tumor, the mass showed invasive growth and grew toward the skin rather than the palpebral conjunctiva. No recurrence occurred when surgically removed with clean margins.