Anne J. Gemensky-Metzler

Semiconductor diode laser transscleral cyclophotocoagulation for the treatment of glaucoma in horses: a retrospective study of 42 eyes.

OBJECTIVE To evaluate the outcome of diode laser transscleral cyclophotocoagulation (TSCP) for the treatment of glaucoma in horses. PROCEDURE Medical records at The Ohio State University were reviewed. All horses that underwent diode laser TSCP between the years of 1995 and 2007 were included. Preoperative, procedural and clinical follow-up data were collected, and telephone follow-up was performed. RESULTS Forty-two eyes of 36 horses were included. Twenty-four hours prior to surgery mean intraocular pressure (IOP) was 37.17 + or - 13.48 mmHg (42 eyes). Forty-one of 42 eyes (98%) were sighted and 39 of 39 (100%) of eyes were receiving topical glaucoma medication. At 3-5 weeks postoperatively the average IOP was 19.36 + or - 12.04 mmHg (22 eyes). IOP remained significantly lower than pretreatment values at all periods of clinical follow-up (P < 0.05). There was no significant difference in vision outcome, or the requirement for topical glaucoma medication relative to pretreatment values at any follow-up period. Hyphema in 5 of 42 eyes was the only complication noted. Of the 27 eyes seen for clinical follow-up, 2 were enucleated because of refractory elevation of IOP. Mean telephone follow-up was 49 months. Twenty-one of 22 owners contacted (95%) reported that the treatment had been of value, 14 of 22 eyes (64%) were receiving topical glaucoma medication, and 13 of 22 eyes (59%) were considered sighted. CONCLUSIONS Diode laser TSCP aided in the control of IOP and maintenance of vision but did not eliminate the need for topical glaucoma medication during the period of clinical follow-up.

In vivo effects of adjunctive tetracycline treatment on refractory corneal ulcers in dogs

OBJECTIVE To evaluate effect of adjunctive treatment with tetracycline analogues on time to complete corneal reepithelialization in dogs with nonhealing (ie, refractory) corneal ulcers. DESIGN Randomized controlled clinical trial. ANIMALS 89 dogs with refractory corneal ulcers. PROCEDURES Corneal ulcers were treated via debridement and grid keratotomy. Dogs were assigned to receive 1 of 3 treatment regimens for up to 6 weeks: doxycycline (5 mg/kg [2.27 mg/lb], PO, q 12 h) with topically applied ophthalmic ointment containing neomycin, polymyxin B, and bacitracin (ie, triple antibiotic ointment; q 8 h); cephalexin (22 mg/kg [10 mg/lb], PO, q 12 h) with topically applied oxytetracycline ophthalmic ointment (q 8 h); or a control treatment of cephalexin (22 mg/kg, PO, q 12 h) with topically applied triple antibiotic ointment (q 8 h). Healing was monitored via measurements of the wound with calipers and evaluation of photographs obtained every 2 weeks. Treatment effectiveness was evaluated by wound healing and decreased signs of pain. RESULTS The Boxer breed was overrepresented in all groups. At the 2-week time point, wound healing was significantly more common in small-breed dogs, compared with large-breed dogs. Dogs treated with oxytetracycline ophthalmic ointment had a significantly shorter healing time than did dogs receiving the control treatment. Corneal ulcers in dogs that received doxycycline PO healed more rapidly than did ulcers in dogs in the control treatment group; however, this difference was not significant. CONCLUSIONS AND CLINICAL RELEVANCE Topical tetracycline ophthalmic ointment was a safe, inexpensive, and effective adjunctive treatment for refractory corneal ulcers in dogs.

Extra-adrenal paraganglioma of the equine orbit: six cases.

At The Ohio State University from 1994-2006 six of seven horses evaluated for primary orbital disease were diagnosed with extra-adrenal paraganglioma (EAPG). The horses ranged in age from 14 to 24 years, with a mean of 16.8 years. Duration of clinical signs was 1.5 years to 5 years, with a mean of 2.8 years. Clinical signs varied, but all six had non-painful exophthalmus of the right eye. Five horses had complete ocular exams reported; three of five had decreased to absent vision, two of five had pale optic nerves, and in three of five, difficulty of retropulsion of the globe was noted. Diagnostic tests performed included complete blood count, serum profile, radiography, ultrasound, computed tomography, true-cut biopsy, ocular examination, guttural pouch endoscopy, oral examination, and physical examination. Expulsive hemorrhage during orbital exenteration occurred in all horses. In five of six cases, tumor extension through the orbital foramen was apparent intra-operatively. Histopathologic appearance of all surgically removed tissues consisted of sheets of polygonal cells with abundant lightly granular cytoplasm, round nuclei with vesicular chromatin, and rare mitoses. Neoplastic cells were arranged into small groups separated by a fine fibrovascular stroma. All six cases were chromagranin positive on immunohistochemical staining. Follow-up ranged from six months to six years, with a mean of two years. Four of the five horses that recovered from surgery had no apparent tumor recurrence in 6-48 months.

Induction of posterior capsule opacification by hyaluronic acid in an ex vivo model.

PURPOSE Because hyaluronic acid (HA) is found in many surgical viscoelastic agents, this study aimed to determine (1) if HA receptors are present in the canine lens, (2) if the rate of lens epithelial cell (LEC) migration is altered following treatment with HA, and (3) if introduction of exogenous HA into the lens capsule promotes lenticular migration, thus contributing to posterior capsule opacification (PCO). METHODS Normal and cataractous canine LECs were evaluated for expression of the HA receptor CD44 and the receptor for HA mediated motility (RHAMM) using immunohistochemistry, immunoblotting, and real-time PCR. Canine LEC were treated with various concentrations of HA, and induction of migration was monitored over time. Commercially available surgical viscoelastics were utilized ex vivo, and rates of PCO formation were analyzed. RESULTS Basal protein and mRNA expression of both CD44 and RHAMM was noted. Cataractous canine LEC demonstrated significantly (P < 0.01) higher expression of CD44 but not RHAMM. Treatment with higher concentrations of HA resulted in a significant (P < 0.01) increase in CD44 mRNA and increased LEC migration in vitro. Use of CD44-neutralizing antibodies confirmed the role of CD44 in HA-induced lenticular migration. Viscoelastic material containing higher concentrations of HA led to increased rates of ex vivo PCO. CONCLUSIONS Exogenous HA can induce lenticular migration and CD44 expression. Use of surgical viscoelastics that contained HA resulted in increased rates of ex vivo PCO suggesting that judicious selection and use of viscoelastic material during cataract surgery is warranted.

Equine glaucoma: a histopathologic retrospective study (1999-2012).

PURPOSE To characterize and describe the histopathologic findings in equine globes enucleated due to glaucoma. METHODS Medical records at The Ohio State University from 1999 to 2012 were reviewed retrospectively. Signalment, history, and treatment data were collected, and histologic slides of enucleated globes were examined and lesions recorded. Twenty-three eyes from 23 horses were eligible for inclusion in this study. RESULTS The majority of affected horses were > 15 years of age (65%). The ages ranged from 5 to 35 years (mean = 17.4 years). The left eye was affected in 10 cases (43%) and the right eye in 13 cases (57%). There were 13 mares (56%) and 10 geldings (44%). Quarter Horses (30%), Appaloosas (26%), and Thoroughbreds (22%) were the most common breeds in the study population. The most common histopathologic changes included hypercellularity of the optic nerve (93%), retinal atrophy (89%), corneal vascularization (83%), descemetization of pectinate ligaments (83%), hypercellularity of the anterior corneal stroma (75%), posterior bowing of the iris base (74%), ciliary body atrophy (74%), corneal striae (70%), pars plana elongation (60%), cataract (53%), and collapsed ciliary cleft/trabecular meshwork (52%). Evidence of uveitis (cataract, lymphoplasmacytic infiltration of the uvea, and/or anterior or posterior synechiae) was present in 20/23 eyes (87%). CONCLUSIONS Equine glaucoma most commonly occurs secondary to uveitis with Appaloosas and older horses predisposed. Histologic changes are comparable to prior reports of chronic glaucoma; notable findings not previously described in the horse were posterior bowing of the iris base and relative sparing of the superior retina from atrophy associated with elevated IOP.

Evaluation of Advanced Glycation End–Products in Diabetic and Inherited Canine Cataracts

BackgroundThe receptor for advanced glycation end-products (RAGE) increases in the human cataract and should correlate with increased DNA damage and proliferation of lens epithelial cells (LECs). The purpose of this study was to measure and immunolocalize RAGE in normal and cataractous canine LECs, and to determine whether there was a correlation between RAGE and DNA damage (gadd45), cell-cycle regulation (p21), and LEC proliferation (proliferating cell nuclear antigen, PCNA).MethodsThirty-two anterior lens capsules from 22 dogs that underwent cataract surgery and 10 lenses from dogs with normal eyes were evaluated. Eleven of the cataractous lenses were from diabetic patients (n=16), and eleven were from patients with inherited cataracts (n=16). Standard immunohistochemical staining was performed using antibodies against RAGE, gadd45, p21, PCNA, α-smooth muscle actin, and TGF-β. Immunostaining intensity for each antibody was given a score of 0–4+. Standard Western blot analysis on normal and cataractous lens capsules was performed using the same antibodies as in the immunohistochemical staining. Comparisons were also made based on age and sex. Real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) was performed for RAGE.ResultsThere was an increase in RAGE expression with age in normal LECs, but no significant difference was seen when normal adult LECs were compared to cataractous LECs. The stage of the cataract and the presence of LIU were not associated with a significant increase in RAGE expression. There was no age-dependent difference in the normal lenses for gadd45, p21, or PCNA. Significant up-regulation of p21 (P<0.05) and PCNA (P<0.05) was seen in diabetic cataracts compared to inherited cataracts.ConclusionRAGE and PCNA expression did not increase with cataractogenesis, possibly due to overexpression associated with normal aging and constant exposure to oxidative stress from sunlight-related ultraviolet irradiation, respectively. However, p21 and PCNA increased in diabetic cataractogenesis suggesting cell cycle and proliferation dysregulation. This may be related to the rapid onset in this type of cataract compared with the more chronic and slower-to-develop inherited cataracts.

The long‐term effects of semiconductor diode laser transscleral cyclophotocoagulation on the normal equine eye and intraocular pressurea

OBJECTIVE To describe the long-term histologic and intraocular pressure (IOP) lowering effects of diode laser transscleral cyclophotocoagulation (TSCP) on the normal equine eye. ANIMALS Eight normal adult horses. PROCEDURES TSCP was performed in one randomly assigned eye. Sixty spots were treated at settings of 1500 ms and 1500 mW. Two horses were randomly selected for euthanasia at 2, 4, 12, or 24 weeks post-TSCP. Both eyes were enucleated and histologically evaluated. Intraocular pressure was measured by applanation tonometry prior to TSCP, immediately post-TSCP, twice daily for 7 days post-TSCP and then monthly until study conclusion. A longitudinal model estimated the average IOP values for the treated and untreated eyes at 1 week, 1, 3, and 6 months post-TSCP. RESULTS All treated eyes at all time periods exhibited four characteristic histologic lesions: scleral collagen hyalinization, ciliary body pigment dispersion and clumping, focal disruption of the ciliary body epithelium, and focal ciliary process atrophy. After TSCP, there were no significant changes in IOP from baseline for the control eyes, while the IOP in treated eyes was significantly decreased from baseline (P < 0.05) at all time periods. The estimated decrease in IOP in the treated eyes compared to baseline IOP at 6 months was -3.76 mmHg for an average decrease in IOP of 20% from baseline. CONCLUSION Diode laser TSCP produces histologic lesions in the equine ciliary body that result in a significant and sustained decrease in IOP. TSCP may be an effective management for equine glaucoma.

A modified ab externo approach for suture fixation of an intraocular lens implant in the dog.

The goals of canine cataract and lens instability surgery should be to ensure a small incision, minimal tissue trauma, shortened surgical time, maintenance of the anterior chamber, and restoration of emmetropia through the use of a stable intraocular lens specifically designed for the canine eye. While this is usually the case with routine phacoemulsification and in-the-bag intraocular lens implantation, it is often not the case with lens instability, lens luxation or large posterior capsular ruptures. In such cases the incisions are often larger, surgical time and tissue trauma are excessive, and the patient is often left aphakic. The goal of this paper is to present a modified ab externo technique designed to allow removal of the lens and placement of a ciliary sulcus sutured IOL through a small incision, with minimal trauma and shortened surgical time. Use of this technique may allow more canine patients to be emmetropic postoperatively. In addition, the ease of this procedure may encourage earlier removal of an unstable lens and decrease the risk of secondary glaucoma and retinal detachment that occur in association with lens luxation.

Safety study of capsular tension ring use in canine phacoemulsification and IOL implantation

OBJECTIVE To evaluate and compare surgical outcome and complications in canine eyes with stable, cataractous lenses undergoing routine phacoemulsification and intraocular lens (IOL) implantation with or without implantation of a capsular tension ring device (CTR). PROCEDURES Dogs undergoing routine bilateral phacoemulsification and IOL implantation had one eye randomly chosen to have a CTR (47 eyes) inserted while the contralateral eye served as a control (47 eyes). The CTR was placed in the capsular bag following phacoemulsification and immediately prior to IOL implantation. All eyes received acrylic foldable IOLs. Patients were evaluated intra- and postoperatively, and complications were compared between eyes with and without a CTR. RESULTS There were no intra-operative complications associated with implantation of the CTR. Postoperatively, the overall incidences of glaucoma (6%), intraocular hemorrhage (4%), and retinal detachment (2%) were equal between control and CTR eyes at the time of last follow-up. There was no significant difference in overall incidence of immediate postoperative uveitis (35% vs. 38%) or fibrin (19% vs. 15%) between control and CTR eyes. Follow-up time ranged from 2 weeks to 21 months. CONCLUSION In canine eyes with stable cataractous lenses undergoing routine phacoemulsification and IOL implantation placement of a CTR does not increase the risk of intra- or postoperative complications.

Retrospective study of the prevalence of keratoconjunctivitis sicca in diabetic and nondiabetic dogs after phacoemulsification

OBJECTIVE To evaluate the prevalence of keratoconjunctivitis sicca (KCS) in diabetic and nondiabetic dogs following phacoemulsification. PROCEDURES Medical records were reviewed for signalment, body weight, diabetes status, and STT at the preoperative and all postoperative examinations. A clinical diagnosis of KCS was defined as a STT <15 mm/min with compatible clinical signs. Schirmer tear test values and the prevalence of KCS based on STT <15 mm/min were evaluated at 2-4, 5-8, 9-14, 15-20, and 41-52 weeks postoperatively. Size of dog (large, >10 kg; small, ≤10 kg) and STT ranges (<15 mm/min, 15-22 mm/min and >22 mm/min) were categorized for analysis of effect of body weight and STT on prevalence of KCS. RESULTS One hundred and seventeen nondiabetic (198 eyes) and 118 diabetic dogs (228 eyes) were evaluated. KCS was diagnosed in nearly twice as many diabetics as nondiabetics (27.4% vs. 15.4%) within 2 weeks postoperatively (P = 0.0088). Percentage of eyes with KCS among all dogs decreased over time and did not differ significantly after the first postoperative visit. Diabetic small dogs were 1.7 times more likely to have KCS than nondiabetic small dogs (P = 0.0052). Preoperative STT was significantly associated with likelihood of postoperative KCS among large (P < 0.0001), but not small dogs (P = 0.0781). Among large dogs, eyes with STTs between 15 and 22 mm/min were approximately 3 times more likely to be diagnosed with KCS after surgery than those with STT >22 mm/min. CONCLUSION The greatest risk for KCS for all dogs is during the first 2 weeks postoperatively. Populations at greatest risk for postoperative KCS are small dogs, small diabetic dogs, and large dogs with preoperative STT ≤22.