A new, minimally invasive procedure for dogs with encapsulated Ahmed drainage implants and elevated intraocular pressures: A case series.

OBJECTIVE: To describe a novel, minimally invasive method for re-establishing aqueous humor outflow in dogs with refractory glaucoma after fibrous encapsulation of their Ahmed drainage implants. PROCEDURE: Three dogs (4 eyes) underwent trans-capsular implantation of an Alcon EX-PRESS® glaucoma filtration device under sedation (2 dogs) or general anesthesia (1 dog). After rotating the eye downwards, a 2 mm incision was made in the conjunctiva/Tenon's capsule overlying the encapsulated Ahmed plate, and later closed with absorbable suture. All eyes received subconjunctival mitomycin-C 0.02 mg. RESULTS: Mean post-operative follow-up was 341 days (range: 77-530). All eyes were hypertensive pre-operatively (mean IOP: 31.25 ± 7.14 mmHg) despite receiving topical latanoprost (4/4), timolol (4/4), carbonic anhydrase inhibitors (4/4), and demecarium bromide (2/4). Two eyes (dogs 1 and 2) were visual pre-operatively, while 2 eyes (dog 3) displayed equivocal or no vision. Post-operatively, all eyes received timolol and a carbonic anhydrase inhibitor. Other anti-hypertensive medications were discontinued. Immediately following surgery, all eyes were mildly hypotensive (mean IOP: 5.75 ± 1.71 mm Hg). Two of 4 eyes were normotensive and visual until days 90 (dog 2) and 530 (dog 1) (IOP range: 10-16 mm Hg). One eye (dog 3) was normotensive for approximately 150 days, and then hypertension returned. One eye (dog 3) from the start displayed severe uveitis, hypertensive episodes, and was phthisical by the end of follow-up. CONCLUSIONS: Trans-capsular EX-PRESS® implantation is a minimally invasive procedure for treatment of refractory glaucoma in dogs with encapsulated Ahmed drainage implants, and further investigation is warranted.

Fluoroscopically guided neocanalization for treatment of nasolacrimal atresia in two horses.

CASE DESCRIPTION: A yearling Thoroughbred stallion and an 8-year-old Saddlebred mare were evaluated for persistent mucoid ocular discharge. CLINICAL FINDINGS: Examination of both horses revealed copious yellow-tan mucoid ocular discharge with a negative Jones I test, absent nasal punctum, and unsuccessful anterograde nasolacrimal duct (NLD) irrigation. Clinical abnormalities were present on the right side only in one horse and bilaterally in the other. Computed tomography (CT) with contrast confirmed nasolacrimal duct atresia in both horses. TREATMENT AND OUTCOME: Under general anesthesia, the affected NLD was catheterized anterograde and contrast injected. Using fluoroscopic guidance, retrograde access to the distal NLD was obtained for through-and-through wire access. Over the wire, the stoma was dilated and a temporary stent placed for 4-8 weeks. After the procedure, both horses were comfortable and free of ocular discharge at the minimum time of last follow-up, 9 months postoperatively. CLINICAL RELEVANCE: Fluoroscopically guided neocanalization is a viable alternative to traditional surgical approaches for NLD atresia, especially when access to the site of obstruction is limited.

Development and assessment of a novel ex vivo corneal culture technique involving an agarose-based dome scaffold for use as a model of in vivo corneal wound healing in dogs and rabbits.

OBJECTIVE: To develop and assess a novel ex vivo corneal culture technique involving an agarose-based dome scaffold (ABDS) for use as a model of in vivo corneal wound healing in dogs and rabbits. SAMPLE: Corneas from clinically normal dogs (paired corneas from 8 dogs and 8 single corneas) and rabbits (21 single corneas). PROCEDURES: 8 single dog corneas (DCs), 1 DC from each pair, and 10 rabbit corneas (RCs) were wounded with an excimer laser; 1 DC from each pair and 11 RCs remained unwounded. Corneas were cultured for 21 days on ABDSs (8 pairs of DCs and all RCs) or on flat-topped scaffolds (8 single DCs). The surface area of corneal fluorescein retention was measured every 6 (DCs) or 12 (RCs) hours until full corneal epithelialization was detected. Changes in corneal clarity were evaluated at 0, 7, 14, and 21 days. RESULTS: Median time to full epithelialization for wounded dog and rabbit corneas was 48 and 60 hours, respectively; among wounded DCs, time to full epithelization did not differ by scaffold type. After 21 days of culture on ABDSs, all DCs and RCs that epithelialized developed a circular, diffuse, cloud-like pattern of optical haze, whereas DCs cultured on flat-topped scaffolds developed a focal, crater-like region of optical haze. All corneas on the ABDSs maintained convex curvature throughout the study. CONCLUSIONS AND CLINICAL RELEVANCE: Wounded ex vivo DCs and RCs cultured on ABDSs reliably epithelialized, formed optical haze (consistent with in vivo wound healing), and maintained convex curvature. This culture technique may be adaptable to other species.

Microphthalmia, corneal dermoids, and congenital anomalies resembling Goldenhar syndrome in a cat.

CASE DESCRIPTION An 18-month-old spayed female domestic shorthair cat was evaluated because of conjunctivitis and skin-fold dermatitis secondary to bilateral microphthalmia, corneal dermoids, and ankyloblepharon. CLINICAL FINDINGS Physical examination revealed bilateral microphthalmia, bilaterally symmetrical corneal dermoids, ankyloblepharon, superior and inferior entropion, prognathism, and facial asymmetry with deviation of the nasal septum. Computed tomography revealed malformed, thickened bony orbits with mineralization of the orbital ligament bilaterally. Moderate rightward deviation of the nasal septum and ventral nasal meatus was also evident, with no identifiable maxillary sinuses. Results of MRI of the brain were unremarkable. Abdominal ultrasonography showed an irregularly marginated left kidney and a right kidney defect suggestive of chronic renal infarction. An abnormal, well-demarcated, focally thickened region of the muscularis externa of the jejunum was also evident. TREATMENT AND OUTCOME Transpalpebral enucleation was performed bilaterally. Histologic examination of ocular tissues confirmed the corneal dermoids and microphthalmia with anterior and posterior segment dysgenesis and cataracts in both eyes. Ocular discomfort resolved after postoperative recovery, and follow-up revealed that the patient's activity level and quality of life were excellent. No clinical signs of upper respiratory, urinary, or gastrointestinal tract disease were observed during the approximately 3.5-year follow-up period. CLINICAL RELEVANCE The congenital abnormalities observed resembled those described for human patients with Goldenhar syndrome, and the outcome of treatment was favorable. This report may prompt clinicians to consider this diagnosis when evaluating young cats with similar clinical signs.

Assessment of Topical Therapies for Improving the Optical Clarity Following Stromal Wounding in a Novel Ex Vivo Canine Cornea Model.

Purpose: To evaluate the effect of topical suberanilohydroxamic acid (SAHA) and 5-methyl-1-phenyl-2[1H]-pyridone (pirfenidone) on the degree of corneal haze in the stromal wounded ex vivo canine cornea. Methods: Twenty-four corneoscleral rims from normal dogs were uniformly wounded with an excimer laser and placed into culture medium with an air-liquid interface. The control group (n = 8) contained placebo-treated corneas. Treatment group 1 (n = 8) received SAHA topically every 6 hours. Treatment group 2 (n = 8) received pirfenidone topically every 6 hours. Each cornea was fluorescein stained and macrophotographed every 6 hours to assess epithelialization rate. All corneas were also macrophotographed weekly to assess optical clarity (haze). Images were analyzed for differences in pixel intensity between wounded (haze) and unwounded (nonhaze) regions, and haze surface area for each cornea was calculated. Results: The mean epithelialization time was 47.25 hours in the control group, 45.00 hours in the SAHA group, and 43.50 hours in the pirfenidone group, revealing no significant difference (P = 0.368). The median difference in pixel intensity between haze and nonhaze areas was 21.5 in the control group, 8.0 in the SAHA group, and 8.0 in the pirfenidone group, which is significant (P < 0.01). The median haze surface area was 12.96 mm2 in the control group, 5.70 mm2 in the SAHA group, and 5.92 mm2 in the pirfenidone group, which is significant (P < 0.01). Conclusions: Stromal-wounded ex vivo canine corneas exhibited greater optical clarity when treated with SAHA and pirfenidone than when placebo treated at 21 days. There was no significant difference in epithelialization rate between groups. Corneal contour was correlated with geographic haze distribution.

Development and Assessment of a Novel Canine Ex Vivo Corneal Model.

PURPOSE: To develop a novel ex vivo extended culture model of canine corneal epithelial cell wound healing. MATERIALS AND METHODS: Canine corneoscleral rims (CSR) were obtained and, after preparation for culture, were placed on a nutating scaffold and incubated in physiological conditions. In experiment 1, eight CSR in a serum-containing antimicrobial-fortified medium were monitored for epithelial integrity and bacterial infection up to 28 days in culture. CSR were assessed histologically at the end of the culture period end points 0, 7, 14, and 28 days with accompanying scanning electron microscopic (SEM) and transmission electron microscopic (TEM) evaluation. Samples for microbial culture were obtained at days 0, 3, 7, 14, and 28. In experiment 2, uniform 8-mm-diameter superficial corneal epithelial wounds were created and monitored for re-epithelialization in the same culture conditions or in a serum-free protein equivalent medium, with four CSR per group. Standardized digital images were obtained with cobalt filter at the time of fluorescein staining and media change every six hours. Image J imaging software was used to measure the area of fluorescein retention. Re-epithelialization rates were calculated and CSR then fixed for immunohistochemistry (IHC). RESULTS: All corneas survived to end points as described in experiment 1 with no evidence of contamination or compromised epithelial integrity. Histologically, a multilayered epithelium was maintained and corneal edema was not appreciated until day 14. SEM examination revealed epithelial cell layer confluence and migrating epithelial cells of normal cellular morphology with normal cell-cell interactions on TEM. In experiment 2, all eight corneas healed with a healing rate of 0.702 ± 0.130 mm2/h (1.25 mm/day epithelial cell migration rate) and were positive in IHC evaluation for markers of corneal fibrosis. CONCLUSION: This ex vivo canine corneal wound healing model is an appropriate and clinically relevant tool for assessment and modulation of epithelial wound healing.