Canine ocular tumors following ciliary body ablation with intravitreal gentamicin

Iridociliary tumors are the second most common primary ocular tumor in dogs and are usually benign. A review of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) database in 2009 suggested a potential correlation between malignant iridociliary epithelial tumors and ciliary body ablation by intravitreal gentamicin injection for the treatment of glaucoma. The purpose of this case series was to determine whether there is evidence of such a correlation in the COPLOW collection. Mining of the COPLOW database revealed that a significant number (39.5%) of canine globes with a history of ciliary body ablation were subsequently diagnosed with primary ocular tumors at enucleation, most commonly iridociliary epithelial tumors and melanocytic tumors. It is possible that neoplasia was present but unrecognized at the time of ciliary body ablation. These tumors had a higher than expected incidence of malignancy. These cases underscore the importance of reserving ciliary body ablation with gentamicin for disease‐free eyes.     

Multiple ciliary body cysts and secondary glaucoma in the Great Dane: a report of nine cases

Between 1989 and 1995 nine Great Danes were presented to the small animal clinic of the University of Zurich Teaching Hospital with glaucoma and multiple cysts in the anterior and posterior chamber. In four of the nine dogs cysts were present in both eyes; however, bilateral glaucoma was seen in one case only. Mean intraocular pressure (IOP) at initial presentation was 42 mmHg measured by applanation tonometry. With the exception of one dog, all animals were treated medically for a minimum of 13 days. Two animals were subsequently lost to follow up. Two dogs underwent evisceration with implantation of a silicone prosthesis. The glaucomatous globe was enucleated in three dogs. One owner declined surgery and the dog remained buphthalmic with a poorly controlled IOP. One animal remained visual after trans-scleral diode laser cyclophotocoagulation. Histopathology of the three enucleated globes showed multiple cysts originating from the ciliary body epithelium. The mechanism of IOP elevation is probably by anterior displacement of the iris with narrowing of the angle and collapse of the ciliary cleft. A delicate pre-iridal fibrovascular membrane was also seen in each case, which could have also contributed to the elevation of IOP. The high odds ratio of 2.23 (CI 95% 1.14, 3.99) for glaucoma and 37.01 (CI 95% 16.42, 77.81) for ciliary body cysts suggests they are both inherited in this breed. Pedigree analysis of the affected dogs failed to definitely reveal the mode of inheritance.     

Distribution and amount of pigment within the ciliary body and iris of dogs with blue and brown irides

Objective Compare the amount and distribution of pigment in normal canine eyes with blue and brown irides. Animal studied Eighteen mixed‐breed dogs euthanized for population control. Procedures Intact globes were removed immediately following euthanasia. Iris color was noted, and globes were evaluated histologically to determine the distribution of pigment. High magnification (×400) digital images were taken of the dorsal and ventral ciliary processes (CP) of 13 eyes with blue irides and 13 eyes with brown irides. Low magnification (×20) images were taken of the dorsal and ventral portions of the ciliary body (CB) of 14 eyes with blue irides and 14 eyes with brown irides. The images were digitally analyzed to determine the percent of the CP and CB that were pigmented in the high and low magnification images, respectively. Results Eyes with brown irides contained abundant melanin pigment around the CB musculature. This pigment was absent in eyes with blue irides, and the difference was statistically significant (P = 0.001) when digitally analyzed using the low magnification images. Iris color did not have a significant (P = 0.34) impact on the amount of melanin within the CP, as determined using the high magnification images. Conclusions Compared to eyes with brown irides, eyes with blue irides lack pigment around the CB musculature, but contain comparable amounts of pigment in the CP.     

Aqueous misdirection and ciliary block (malignant) glaucoma after cataract removal in a llama

Ciliary block (malignant) glaucoma is caused by the posterior flow of aqueous humor into or behind the vitreous. It is a rare complication of anterior segment surgery in humans. This is a report of ciliary block glaucoma occurring as a postoperative complication of cataract surgery in a llama. Medical management was ineffective in lowering intraocular pressure (IOP). Posterior capsulotomy and anterior hyaloid disruption with a 22-gauge needle, in addition to medical management maintained IOP in the normal range until anterior vitrectomy could be performed. After vitrectomy, glaucoma resolved and medical treatment was no longer necessary.     

Light-microscopy evaluation of zonular fiber morphology in dogs with glaucoma: secondary to lens displacement

Lens displacement resulting in secondary glaucoma is common in terrier breeds. This study was carried out to evaluate whether light microscopy was useful in detecting abnormal patterns in zonular fiber protein. Eyes from 63 dogs with glaucoma secondary to lens displacement were evaluated for the presence of abnormal zonular fiber morphology using the following stains: hematoxylin and eosin, periodic acid Schiff (PAS), Masson's trichrome and Verhoeff's elastin stains. Two distinct forms of abnormal zonular fiber morphology were recognized and designated as zonular fiber dysplasia (ZFD) and zonular fiber collagenization (ZFC). ZFD protein morphology was characterized by being tightly adherent to the nonpigmented ciliary body epithelium, exhibiting a distinct lamellar and cross-hatched pattern and staining strongly positive with PAS and trichrome stains, and staining negative with elastin stains. ZFD was predominant in terrier breeds (18 of 29) and Shar-Pei dogs (4 of 29). ZFC abnormality was characterized by excessive zonular fiber that was not tightly adherent to the ciliary body epithelium and staining positive with PAS, trichrome (blue for collagen) and elastin stains. Only 7 of 19 dogs with ZFC changes were terrier breeds, and there was no pattern in the breeds affected. Fifteen of the 63 dogs used in the study had normal appearing zonular fibers. The staining pattern in these dogs matched normal controls by staining positive with PAS and Verhoeff's elastin stains and had only minimal positive staining with Masson's trichrome stain. Results suggest that light microscopy is useful in detecting breed-related changes in zonular fiber morphology in cases of glaucoma secondary to lens displacement. These changes may correlate with the presence of abnormal zonular fiber proteins and might be important in the pathogenesis of primary lens displacement in terrier and Shar-Pei dogs.     

Serum concentrations of leptin and adiponectin in dogs with chronic kidney disease

BackgroundAn imbalance in adipokines is associated with the progression of chronic kidney disease (CKD) in humans. However, alterations in adipokines in dogs with CKD remain unclear.ObjectivesTo examine whether adipokine concentrations in serum differ between healthy dogs and dogs with CKD and to determine the correlation between serum adipokine concentrations and CKD severity in dogs.AnimalsTwenty dogs with CKD and 10 healthy dogs.MethodsIn this cross‐sectional study, serum concentrations of leptin, adiponectin, interleukin (IL)‐6, IL‐10, IL‐18, and tumor necrosis factor (TNF)‐α were measured in healthy dogs and dogs with CKD, which were classified according to the International Renal Interest Society guidelines.ResultsSerum leptin concentrations were positively correlated with systolic arterial blood pressure (r = .41), creatinine concentrations (r = .39), and symmetric dimethylarginine concentrations (r = .73). Serum adiponectin concentrations (median [range]) in CKD dogs with borderline or non‐proteinuric (20.25 [14.9‐45.8] ng/mL) were significantly higher than those in proteinuric CKD dogs (13.95 [6.4‐22.1] ng/mL; P = .01). Serum IL‐6 (median [range]; 43.27 [24.30‐537.30] vs 25.63 [6.83‐61.03] pg/mL; P = .02), IL‐18 (median [range]; 25.98 [11.52‐280.55] vs 10.77 [3.53‐38.45] pg/mL; P = .01), and TNF‐α (median [range]) concentrations (11.44 [8.54‐38.45] vs 6.105 [3.97‐30.68] pg/mL; P = .02) were significantly different between proteinuric and borderline or non‐proteinuric CKD dogs.Conclusions and Clinical Importanceleptin and adiponectin concentrations in serum might be associated with severity of CKD and proteinuria in dogs with CKD, respectively.     

Cullen frontal sinus valved glaucoma shunt: preliminary findings in dogs with primary glaucoma

PURPOSE: To evaluate the efficacy of a novel, professionally manufactured, frontal sinus valved glaucoma shunt in maintaining normal intraocular pressure (IOP) and vision in dogs with primary glaucoma. METHODS: Three eyes of three dogs diagnosed with primary glaucoma were included in this prospective clinical study. A Cullen frontal sinus valved glaucoma shunt was implanted into each glaucomatous globe. Dogs were treated postoperatively with topical neomycin/polymyxin B/0.1% dexamethasone and 0.03% flurbiprofen every 6 h tapered over 8-12 weeks, and meloxicam at 0.1 mg/kg orally every 24 h for 7-10 days. IOP, intracameral shunt position and apparent patency, and vision were assessed twice daily for up to 4 (n= 3 eyes) and 10 (n= 2 eyes) days postoperatively, and then at re-examination periods of up to 36 weeks (n= 1 eye). Postoperative complications were recorded and documented photographically. RESULTS: Normal IOP was maintained in all shunted globes (range 10-29 mmHg; mean = 16.7 mmHg at 24 h; IOP = 23 mmHg at 36 weeks) postoperatively for 2 days (3/3 eyes), 8 weeks (2/2 eyes), and 36 weeks (1/1 eye) without additional antiglaucoma therapies. Photopic vision and shunt position and patency were maintained in all shunted globes for all follow-up periods. Postoperative complications included mild aqueous flare and fibrin (n= 3 eyes for 3-10 days postoperatively); intracameral shunt occlusion with fibrin (n= 1 eye at days 2 and 4); partial anterior chamber tube extrusion (n= 1 eye at day 4), and focal corneal edema (n= 1 eye at 18 weeks). Tissue plasminogen activator injected intracamerally through the silicone tube near the frontal sinus effectively resolved the fibrinous shunt occlusion. CONCLUSIONS: The Cullen frontal sinus valved glaucoma shunt shows promise for the management of canine primary glaucoma.     

Combined transscleral diode laser cyclophotocoagulation and Ahmed gonioimplantation in dogs with primary glaucoma: 51 cases (1996-2004)

OBJECTIVE: To evaluate the combined diode laser cycloablation procedure and adjunctive Ahmed gonioimplant use in dogs with primary glaucoma. DESIGN: Retrospective study. ANIMALS: 48 dogs, 51 eyes with primary glaucoma. PROCEDURE: Medical records from two large private clinical ophthalmology services were reviewed. Signalment, duration of glaucoma, gonioscopic evaluation, laser power and duration settings, immediate postoperative and final intraocular pressure and visual results, short and long-term visual outcome, and surgical complications were recorded. RESULTS: The age range of affected dogs was 3.0-14.0 years, with a mean age of 7.5 +/- 2.6 years. Eleven pure breeds were represented, with the most common being the American Cocker Spaniel. The sex distribution was 22 neutered males, 1 intact male, 23 spayed females, and 2 intact female dogs. The right eye was affected in 33 cases, and the left eye in 18 cases. The average total joules, which was administered with the diode laser, was 109.6 +/- 23.6 J. Immediate surgical complications included fibrin formation in the anterior chamber (15), corneal ulcers (4), hyphema (7), and focal retinal detachment (1). Long-term complications included cataract formation (8 total, 2 of which were significant, vision-threatening), elevated intraocular pressure (IOP) (6), unstable gonioimplant (1), and glaucoma recurrence (14). Additional surgeries performed on the eyes over the course of study included: intrascleral prosthesis (4), enucleation (1), resection of fibrotic scar tissue (5), and repeat laser cycloablation (8). The dogs were examined for a mean follow-up time of 17.6 months (range: 2-83 months postoperatively). Twenty-nine cases were followed greater than one year. Vision was maintained in 42/51 eyes (82%) in the immediate short-term of this study. In all cases included in the study, good control of IOP was achieved in 39/51 (76%) of eyes, and IOP was poor or uncontrolled in 12/51 (24%) of eyes. Twenty out of 41 eyes (49%) maintained fair to excellent vision six months after surgery. Twelve months postoperative observations demonstrated that 12/29 (41%) of the eyes were still visual. CONCLUSIONS: In primary glaucoma, the combined procedure of laser diode cyclophotocoagulation and Ahmed valve implant was associated with return or maintenance of vision in 42/51 eyes (82%) in the immediate short-term of this study, and a long-term IOP control in 39/51 (76%) of the cases, with 12/29 eyes (41%) visual after 12 months.     

Three-dimensional reconstruction of the angioarchitecture of the ciliary body of the West Indian manatee (Trichechus manatus)

OBJECTIVE: To examine the angioarchitecture of the ciliary body in the West Indian manatee (Trichechus manatus), through the use of three-dimensional reconstruction. PROCEDURE: Specimens from West Indian manatee were preserved in 10% buffered formalin, embedded in paraffin, serial sectioned and stained by Masson trichrome for light microscopic three-dimensional reconstruction and evaluation. RESULTS: The network of blood vessels in the ciliary processes of the West Indian manatee is fed by the major arterial circle that lies mostly near the base of the iris. The branching arterioles give rise to a capillary-sinusoidal bed that extends internally along each process, emptying into two sets of veins, one being elevated. The elevated and nonelevated veins join posteriorly before emptying into the choroidal venous system. CONCLUSIONS: The angioarchitecture of the ciliary body of the West Indian manatee is clearly unique when compared to those previously examined in land mammals. Three-dimensional reconstruction of paraffin sections is an effective means to evaluate vascular patterns in ocular specimens, especially those unavailable for corrosion casting.     

Progressive changes in ophthalmic blood velocities in Beagles with primary open angle glaucoma

Objective To measure changes in the ocular and orbital blood flow velocities by color Doppler imaging (CDI) in beagles with primary open angle glaucoma as the disease progressed from early to advanced stages. Methods CDI measurements were performed periodically on 13 glaucomatous Beagles during the nontreated mild, moderate and advanced stages of POAG over the course of 4 years. CDI was performed with the dogs lightly anesthetized (butorphanol 0.1 mg/kg IV, acepromazine maleate 0.02 mg/kg IV, and atropine sulfate 0.05 mg/kg) while the CD transducer was placed directly on the cornea anesthetized with 0.5% tetracaine hydrochloride. Intraocular pressure (IOP) by pneumatonography or TonoPen XL, heart rate and mean arterial blood pressure were measured at the beginning, middle and end of each study. The ophthalmic vessels examined included: external ophthalmic arteries and veins, long and short posterior ciliary arteries, anterior ciliary arteries and veins, primary retinal arteries, and vortex veins. Recordings of each vessel included peak systolic velocity (PSV), end diastolic velocity (EDV) and time averaged velocity (TAV), and when possible the resistive index (RI) and pulsatility index (PI) were computed. Results CDI abnormalities were present before intraocular pressure exceeded the normal range. As the animals aged, and the glaucoma progressed with higher levels of IOP, significant changes occurred in nearly all vessels, and generally included a major increase in RI (P < 0.001) and an increase in the PI (P < 0.001). Mean arterial blood pressure (105 ± 18 mmHg) and heart rate (118 ± 33/min) remained reasonably constant. The IOP gradually increased as the disease progressed (early and normotensive: 19.4 ± 3.9 mmHg; moderate: 29.7 ± 2 mmHg; and advanced: 44.5 ± 6 mmHg). The ocular veins seemed most influenced early on in the disease. Late in the disease, ocular venous blood flow could not be consistently demonstrated. An increase in the PI of ocular veins occurred in the moderately and severely affected glaucomatous Beagles. As the IOP increased, there were trends of increasing resistive index and pulsatility index in most arteries, and periods of marked decreased velocities of the vortex and external ophthalmic veins in severe cases. Conclusion CDI measurements in Beagles with primary open angle glaucoma during the course of 4 years indicate easily measurable and repeatable progressive blood flow abnormalities before the elevation of IOP and, thereafter, with gradually increased levels of IOP.