Risk factors for corneal conjunctival grafting failure in dogs at four referral centers in the southern United States (203 patients): 2015-2021.

OBJECTIVE: To report risk factors associated with conjunctival graft failure in dogs at four referral specialty centers. PROCEDURES: Records of 203 dogs (229 eyes) undergoing conjunctival graft repair of ulcerative keratitis at four hospitals from 2015 to 2021 were reviewed. Success was defined as full graft integration with globe retention at the last postoperative evaluation; vision status was reported separately. Factors assessed included patient signalment, ophthalmic examination findings, surgical factors, and follow-up information. RESULTS: Conjunctival graft failure occurred in 11% (25/229) of eyes and was significantly associated with ulcer depth, with corneal perforations having increased odds of graft failure compared with descemetoceles (odds ratio [OR] = 3.22, 95% confidence interval [CI] 1.11-9.32; p = .03) and stromal ulcers (OR = 10.89 [95% CI 1.38-86.18], p = .02). Brachycephalic dogs were significantly more likely than non-brachycephalic dogs to experience graft failure (OR = 5.02 [95% CI 1.42-17.74], p < .01). Surgery on the opposite eye relative to surgeon handedness was significantly associated with an increased risk of graft failure (OR 4.28 [95% CI 1.53-11.94], p < .01). The use of 7-0 and 8-0 suture versus 9-0 (p = .03) and the use of a combined simple continuous and interrupted pattern (p = .03) were significantly associated with an increased risk of graft failure. At the last follow-up, (median 61.5 days), 87% of dogs were visual. CONCLUSIONS: Corneal perforations, surgery on the opposite eye relative to surgeon handedness, suture size and pattern, and brachycephalic conformation were significantly associated with an increased risk of graft failure in this study. These characteristics can be considered when determining prognosis for ulcerative keratitis requiring surgical intervention.

CLINICAL AND HISTOPATHOLOGIC OCULAR FINDINGS IN AQUARIUM-HOUSED COWNOSE RAYS (RHINOPTERA BONASUS).

Cownose rays (Rhinoptera bonasus) are susceptible to ocular disease with their prominent globes, but despite being popular animals housed in aquaria, there is little published information about their normal ocular anatomy and common pathologic ocular findings. A total of 63 live cownose rays (CNR) from three unrelated, separately housed groups had ocular examinations, and 5 adult rays were selected for ocular ultrasound. All examinations were performed out of the water, and most without anesthesia. Clinical findings were described, categorized, and scored by severity. Sixty-two of 63 rays (123 eyes) had clinical abnormalities, including 110 eyes with corneal pathology (mild = 76, moderate/severe = 34) and 74 eyes with intraocular pathology (mild = 44, moderate/severe = 30). Grey-to-white corneal opacities were the most common pathology (n = 58 rays/100 eyes) followed by cataracts (n = 41 rays/58 eyes), then persistent (or dysplastic) pupillary membranes (n = 14 rays/15 eyes). Most pathologic findings appeared inactive, but one aquarium had several CNR with active ocular pathology. There was a significant association between the diagnosis of moderate/severe corneal and intraocular pathology with age (P = 0.008 and P = 0.014, respectively) and weight (P = 0.001 and P = 0.039, respectively), as well as moderate/severe corneal pathology and group sampled (P = 0.03). There were no other significant variables identified. Additionally, histopathology of 14 eyes (11 rays) from two different facilities were examined, with keratitis (n = 8) and uveitis (n = 2) as the most common lesions. This study shows a high prevalence of pathologic ocular findings in cownose ray eyes with heavier adults more likely to be affected than lighter juveniles. Comprehensive ocular evaluation is important in this species and serial ocular exams and future studies should be pursued to monitor ocular disease progression and better understand possible etiologies.

INTRAOCULAR PRESSURES OF AQUARIUM-HOUSED COWNOSE RAYS (RHINOPTERA BONASUS) WITH NORMAL AND ABNORMAL OPHTHALMIC EXAMS.

Cownose rays (Rhinoptera bonasus) are common elasmobranchs in zoos and aquaria; however, there is a lack of published information regarding ocular findings in this species. Intraocular pressure (IOP) was measured in a total of 52 cownose rays (Rhinoptera bonasus) from two unrelated aquaria (n = 22 from A1, n = 30 from A2) using a TonoVet rebound tonometer on two settings (dog = D, and unidentified species = P) as part of a full ophthalmologic examination. Adult (n = 38) and juvenile (n = 14) rays were sampled out of water briefly in sternal recumbency. Intraocular pressure (mean ± SD [range]) in the D setting (9.10 ± 2.57 [4-18] mmHg) was higher than the P setting (5.21 ± 2.32 [0-12] mmHg) (P<0.001). Statistical analysis revealed no difference in IOP between right and left eyes, and no correlation between body weight and IOP. No differences in IOP between sex, age group, and location were identified in either setting. However, a significant difference was observed between levels of severity of corneal disease in IOP D setting (P=0.006) and P setting (P=0.024), and levels of severity of intraocular disease in IOP D setting (P=0.034) only. This study provides baseline IOP values using rebound tonometry in aquarium-housed cownose rays with apparent corneal and intraocular lesions and reveals that the D setting may be more sensitive in identifying IOP changes in eyes with intraocular disease.

Case Report: Successful Management of Refractory Keratomycosis in an Alpaca Using Penetrating Keratoplasty and Combination Antifungal Therapy (Caspofungin 0.5% and Terbinafine 1%).

Fungal keratitis is a common disease in certain parts of the world and affects several species, including equids, camelids, and homo sapiens, leading to blindness or loss of the eye if the infection is not adequately controlled. Reports of clinical use of antifungals caspofungin and terbinafine are limited across both veterinary and human medical literature. The alpaca presented in this case demonstrates that deep keratomycosis can be caused by Scopulariopsis brevicaulis and Fusarium verticillioides, two previously unreported fungi to cause keratomycosis in camelids. This report demonstrates successful management with a combination of surgery and topical ophthalmic treatment with caspofungin 0.5% solution and terbinafine 1% dermatologic cream, after initially failing treatment with topical voriconazole 1% solution. Combination therapy appears more effective than monotherapy with some fungal organisms, and synergy between antifungal agents is thought to play a role in the success of combination therapy. Surgery to remove the bulk of the fungal infection is especially helpful in cases that fail initial medical therapy.

Histologic effects of MicroPulse™ transscleral cyclophotocoagulation in normal equine eyes.

OBJECTIVE: Determine the immediate post-operative effects of MicroPulse™ transscleral cyclophotocoagulation (MP-TSCPC) in healthy equine eyes. ANIMALS STUDIED: Ten adult horses. METHODS: MP-TSCPC was performed on sedated horses in 12 eyes (4 groups) using the following parameters (power, duration, duty cycle): (1) 2000 mW, 180 seconds, 31.3%; (2) 3000 mW, 180 seconds, 31.3%; (3) 3000 mW, 270 seconds, 31.3%; and (4) 3000 mW, 270 seconds, 50%. Three additional eyes were left untreated (control). Eyes were monitored clinically until euthanasia (mean = 3 hours post-procedure). Histologic sections were assessed with light microscopy and transmission electron microscopy (TEM). RESULTS: MP-TSCPC was well tolerated by sedated horses. Adverse effects were only noted in Group 4: ocular hypertension (n = 3/3), conjunctival burns (3/3), aqueous flare (2/3), and a corneal erosion (1/3). Histologic scoring of Group 4 was statistically greater than other treated groups (1-3) and control eyes (P ≤ .021). TEM showed subtle changes to the mitochondria and plasma membrane infoldings of the basilar surface of the nonpigmented epithelium in all treated eyes. CONCLUSIONS: MP-TSCPC does not cause immediate post-procedure adverse clinical effects or pronounced morphological changes to the ciliary body, except with the highest laser settings evaluated (power 3000 mW, duration 270 seconds, duty cycle 50%).

Novel use of a combination of extracellular matrices for wound healing following resection of a large inferior eyelid mass in a miniature Hereford.

CASE DESCRIPTION: A 9-month-old miniature Hereford heifer was evaluated for a mass on the right inferior eyelid that had progressed in size over 3 months. CLINICAL FINDINGS: Physical examination revealed a firm, ulcerated, pedunculated mass on the right inferior eyelid that extended from the medial quarter to beyond the lateral canthus of the eye. The base of the mass measured 7.4 × 6.7 cm, and the dorsal margin of the base of the mass was approximately 3 mm ventral to the inferior eyelid margin. Histologic evaluation of incisional biopsy specimens from the mass was consistent with fibrosarcoma. TREATMENT AND OUTCOME: The mass was surgically resected with care taken to preserve the eyelid margin. The resulting 10 × 8.5-cm surgical wound was treated with adjunct CO2 laser therapy and closed by primary closure at its medial and central aspects and placement of a 4.6 × 2.6-cm lyophilized equine amnion multilayer graft and 2 sheets of 4-ply porcine small intestinal submucosa at its lateral aspect. The grafts were kept moist by alternating topical antimicrobial and artificial tear ointments for 3 weeks. The wound healed without complications, resulting in a functional and aesthetically pleasing outcome despite the development of moderate ectropion at the lateral aspect of the inferior eyelid. CLINICAL RELEVANCE: Results suggested that a combination of extracellular matrix scaffolds may be an alternative to extensive skin flaps for management of large dermal wounds, particularly wounds resulting from blepharoplasty where preservation of an eyelid margin is desired.

MicroPulse™ transscleral cyclophotocoagulation in the treatment of canine glaucoma: Preliminary results (12 dogs).

OBJECTIVE: To describe the clinical application and effect of MicroPulse™ transscleral cyclophotocoagulation (MP-TSCPC) in dogs with glaucoma. ANIMALS STUDIED: Twelve dogs with primary (n = 8) or secondary (n = 4) glaucoma, aged 2-13 years (mean ± SD, 7.2 ± 3.8 years). PROCEDURES: MP-TSCPC was performed under sedation or general anesthesia. Laser duty cycle was 31.3%, laser power varied from 2000-2800 mW, and each hemisphere was treated for 90-180 seconds. The probe was applied to each quadrant in a "sweeping motion," sparing the 3 and 9 o'clock positions. RESULTS: The number of MP-TSCPC procedures per eye varied from 1 to 3 (1.4 ± 0.7). Intraocular pressure (IOP) was controlled (<25 mm Hg) in 11/12 dogs (92%) within 1-15 days post-operatively. The IOP control at 1 month and the duration between repeated procedures were significantly greater in eyes treated with high energy laser (2800 mW) compared to 2000-2500 mW. Long-term follow-up (315.3 ± 100.7 days) showed controlled IOP in 5/12 (42%) and vision retention in 4/8 (50%) dogs. In unsuccessful cases, loss of IOP control or vision loss occurred within 3-245 days (109.1 ± 93.7 days) and 28-261 days (114 ± 101.6 days), respectively, resulting in a salvage procedure in 6 dogs. Complications were as follows: corneal hypoesthesia (92%), anterior uveitis (67%), post-operative ocular hypertension (50%), neurotrophic corneal ulcer (25%), keratoconjunctivitis sicca (8%), and rubeosis iridis (8%). CONCLUSIONS: MP-TSCPC is a viable tool for managing canine glaucoma, although further studies are required to improve the long-term effect and reduce the complication rate.

Retrospective analysis of ocular neuropathies in diabetic dogs following cataract surgery.

OBJECTIVES: To describe and compare the cumulative incidence and clinical progression of ocular neuropathies in diabetic dogs vs nondiabetic dogs following cataract surgery. METHODS: Medical records of 196 diabetic and 442 nondiabetic dogs who underwent cataract surgery between 2004 and 2015 were reviewed. The percentage of patients affected by neuropathy and potential risk factors were compared between groups. RESULTS: Patients with diabetes mellitus (DM) were 20.4 times more likely to develop an ocular neuropathy than patients without DM (12.24% vs 0.68%). Twenty-four diabetic patients were affected by mononeuropathies or polyneuropathies including Horner's syndrome (n = 20), facial neuropathy (n = 5), and neurogenic keratoconjunctivitis sicca (NKCS) (n = 5). The odds of a diabetic patient developing Horner's syndrome and NKCS were 86.3 and 20.7 times higher than a nondiabetic patient, respectively. The average duration of DM prior to diagnosis of neuropathy was 659 days (range 110-2390 days; median 559 days). Complete resolution was achieved in 10 of 22 neuropathies (45%) within an average of 248 days (range 21-638 days; median 187 days) after diagnosis. CONCLUSIONS: The odds of developing an ocular neuropathy, specifically Horner's syndrome and NKCS, are statistically higher in diabetic patients compared to nondiabetic patients. Neuropathies were observed as a long-term complication in this group of diabetic patients, and complete resolution of the neuropathy was observed in less than half of the affected population.

Retinal detachment and glaucoma in the Boston Terrier and Shih Tzu following phacoemulsification (135 patients): 2000-2014.

OBJECTIVES: To report the cumulative incidence of retinal detachment (RD) and glaucoma following phacoemulsification in Boston Terriers and Shih Tzu in the southeastern United States over a 14-year period and investigate the potential predisposing risk factors. METHODS: Medical records of 83 Shih Tzu and 52 Boston Terriers that underwent phacoemulsification between 2000 and 2014, with or without intraocular lens placement, were reviewed. For a comparison population, phacoemulsification data from 45 Labrador Retrievers, 73 Schnauzers, and 159 Bichon Frises were evaluated. Information collected included signalment, concurrent systemic diseases, preoperative findings, surgical details, postoperative complications, and duration of follow-up. Percentages of patients to develop RD and glaucoma were assessed, as well as potential risk factors. Minimum of 3 months of follow-up after surgery was required for inclusion. RESULTS: Retinal detachment occurred in 7.7% (7/91 eyes) and 8.9% (11/123 eyes) and glaucoma occurred in 38.0% (35/91 eyes) and 29.3% (36/123 eyes) of Boston Terriers and Shih Tzu, respectively. Mean follow-up time was 804 days. Neither Boston Terriers nor Shih Tzu were at increased risk for RD or glaucoma when compared to the other breeds, and no significant risk factors for either breed were identified in the final multivariate analysis. CONCLUSIONS: The cumulative incidence of RD in Boston Terrier and Shih Tzu reported here was in agreement with previously reported nonbreed specific percentages (2.7-8.4%). The cumulative incidence of glaucoma in this population of Boston Terriers and Shih Tzu was higher than previously reported nonbreed specific percentages (5.1-18.8%).