Effect of immediate postoperative intracameral tissue plasminogen activator (tPA) on anterior chamber fibrin formation in dogs undergoing phacoemulsification.

OBJECTIVE: To evaluate the postoperative effect of intracameral tPA (alteplase; Activase®, Genentech, San Francisco, CA), administered at immediate conclusion of phacoemulsification, on anterior chamber fibrin formation in dogs. PROCEDURES: Forty-one dogs (82 eyes) undergoing bilateral phacoemulsification received 25 µg/0.1 mL intracameral tPA in one eye and 0.1 mL unmedicated aqueous vehicle in the contralateral eye immediately after corneal incision closure. Intraocular pressure (IOP) was measured, and severity of anterior chamber fibrin formation, aqueous flare, pigment precipitates on the intraocular lens (IOL) implant, posterior capsular opacification (PCO), and corneal edema were graded at approximately 1 week, 2-3 weeks, 4-6 weeks, 8-12 weeks, and greater than 3 months postoperatively. RESULTS: Anterior chamber fibrin developed postoperatively in 68.3% of dogs (28/41) and 50% of eyes (41/82). In tPA-treated eyes, 53.7% (22/41) developed fibrin compared to 46.3% of control eyes (19/41). Some degree of postoperative ocular hypertension (POH) occurred in 53.7% of dogs (22/41) and 36.5% of eyes (30/82). In tPA-treated eyes, 34.1% (14/41) experienced POH compared to 39% of control eyes (16/41). Additional intracameral tPA injection was later required in 29.3% of both tPA-treated (12/41) and control eyes (12/41). CONCLUSIONS: Administration of intracameral tPA at immediate conclusion of canine phacoemulsification had no clinically observable effect on anterior chamber fibrin incidence at any time point. tPA-treated eyes showed no prophylaxis against POH or secondary glaucoma compared to control eyes and received late postoperative tPA injections at the same frequency as control eyes.

The effects of topical aqueous sirolimus on tear production in normal dogs and dogs with refractory dry eye.

PURPOSE: To evaluate the effect of twice daily aqueous 0.02% sirolimus drops on tear production in normal dogs and dogs with refractory keratoconjunctivitis sicca (KCS). METHODS: Two groups of dogs were studied. Ten normal dogs with no signs of ocular disease were administered topical 0.02% sirolimus ophthalmic solution in right eye, and a vehicle control in the left eye twice daily for 4 weeks. Complete ophthalmic examinations, including Schirmer tear test were performed weekly. Eighteen dogs with refractory KCS were randomly assigned to receive 0.02% sirolumus ophthalmic solution or 0.02% tacrolimus ophthalmic solution twice daily. Complete ophthalmic examinations were was performed at 2 and 6 weeks following treatment. RESULTS: Tear production in the sirolimus-treated eyes of normal dogs was greater when compared to vehicle controls with a mean difference over all time points of 3.46 mm (95% CI 1.17, 5.75; P = 0.006). After 4 weeks of treatment, the mean difference was 5 mm (95% CI 1.95, 8.05; P = 0.002). In dogs with refractory dry eye, 37.5% of eyes treated with sirolimus exhibited increased tear production >4 mm/min after 6 weeks of treatment, compared to 20% of eyes receiving tacrolimus (P = 0.433). One normal dog experienced topical irritation to both sirolimus and vehicle-treatment. Side effects were not reported in any treated eyes with chronic KCS. CONCLUSION: Topical 0.02% sirolimus might be an alternative treatment for canine patients with keratoconjunctivits sicca. The drug appears safe when applied topically in an aqueous suspension for up to 6 weeks. While initial results are promising, further studies are warranted.

Comparison of topically applied flurbiprofen or bromfenac ophthalmic solution on post-operative ocular hypertension in canine patients following cataract surgery.

OBJECTIVE: To compare the prevalence and kinetics of ocular hypertension after routine cataract extraction when using a predominately COX-2 inhibitor (bromfenac) versus a predominately COX-1 inhibitor (flurbiprofen) in combination with a topical corticosteroid. PROCEDURES: Patients undergoing unilateral or bilateral cataract surgery were randomly assigned to receive flurbiprofen or bromfenac at the day of surgery and continued for 6 weeks postoperatively, along with topical neo poly dexamethasone. No systemic nonsteroidal anti-inflammatory medications were administered before or after surgery. Intraocular pressure was monitored pre and postoperatively. When an IOP of >25 mmHg was detected, therapeutic intervention was performed. RESULTS: Eyes in both treatment groups showed a similar IOP profile with the highest mean IOP occurring two hours postsurgery and slowly declining during the next 6 weeks. However, eyes receiving bromfenac had a higher mean IOP at 2 h post-op (22.1 mmHg) than eyes receiving flurbiprofen (18.8 mmHg) and a slower decrease in IOP in the weeks after surgery. Over the course of the study, a higher percentage of eyes receiving bromfenac had therapy discontinued over concerns of elevated IOP compared to eyes receiving flurbiprofen (bromfenac 23.1% and flurbiprofen 9.8%). On average, the risk of having elevated intraocular pressure with bromfenac is 1.04 times higher than with flurbiprofen. CONCLUSION: Elevated postoperative IOP was observed in both treatment groups; however, bromfenac-treated eyes were more likely to require intervention for elevated IOP.

Preoperative findings and visual outcome associated with retinal reattachment surgery in dogs: 217 cases (275 eyes).

OBJECTIVE: Report the correlation of pre-operative findings with visual outcome in dogs undergoing retinal reattachment surgery for giant retinal tears. PROCEDURES: Retrospective analysis of dogs that underwent pars plana vitrectomy (PPV) with silicone oil (SiO) tamponade and endolaser retinopexy at one institution. Recorded parameters included signalment, etiology, and duration of retinal detachment, observable retinal tissue architecture, visual reflexes, lens status, presurgical aqueous flare, visual status postoperatively, and complications. RESULTS: Two hundred and seventeen patients (275 eyes) were included. Common etiologies of detachment were primary vitreoretinal disease (50.5%), lens surgery (35.3%), and hypermature cataracts (6.2%). Immediate postoperative anatomic success was noted in 98% of operated eyes. Maintenance or return of vision was noted in 74.2% of patients (72% of eyes) through the last known follow-up, with return of vision on average 18.5 days postoperatively. In those eyes that regained vision, 71.7% had retained vision at the last known recheck examination, with an average follow-up time of 550 days. Pre-operative findings correlated with postoperative vision included presence of a dazzle reflex, presence of a menace response, and retinal tissue architecture. The most common complications included migration of SiO into the anterior chamber (49.4%), corneal ulceration (25.7%), glaucoma (25.7%), and cataract formation (24.5%). CONCLUSION: Giant retinal tears in dogs can be successfully managed via PPV with SiO tamponade and endolaser retinopexy. Vision was maintained in the majority of cases with long-term follow-up. Patient history and thorough ophthalmic examination with attention to retinal tissue architecture are important in assessing surgical candidacy.

Effect of topical 0.02% tacrolimus aqueous suspension on tear production in dogs with keratoconjunctivitis sicca.

OBJECTIVE: To investigate the effect of 0.02% tacrolimus in aqueous suspension on tear production in dogs with keratoconjunctivitis sicca (KCS). Animals studied One hundred five dogs diagnosed with KCS [Schirmer tear test (STT) < or = 10 mm/min and clinical signs of dry eye]. Eyes with marginally decreased STT (11 < or = 15 mm/min) and clinical signs of dry eye were also evaluated. PROCEDURE: The investigation was conducted in two parts: an initial efficacy study and a subsequent double blinded controlled study. In the efficacy study, the effect of topical tacrolimus (formerly FK-506) on tear production in dogs with primary KCS was evaluated. Dogs were divided into four categories: 1) 59 eyes (38 dogs) naïve to tear stimulation therapy with initial STT < or = 10 mm/min; 2) 28 eyes (21 dogs) naïve to tear stimulation therapy with initial STT 11 < or = 15 mm/min; 3) 30 eyes (15 dogs) maintained successfully on CsA therapy; 4) 47 eyes (24 dogs) unresponsive to CsA therapy. STT and clinical signs were evaluated prior to and after 6 to 8 weeks of twice daily tacrolimus administration. Tacrolimus was substituted for CsA therapy in categories 3 and 4. The controlled study compared the effect of topical tacrolimus in aqueous suspension to administration of the aqueous carrier alone on tear production in 20 dogs with primary KCS. RESULTS: In the efficacy study, STT increased by 5 mm/min in 84.7%, 25.0%, 26.7% and 51.1% of eyes in categories 1, 2, 3 and 4 respectively after tacrolimus administration. Eighty-three percent of eyes with extremely low initial STT (< or = 2 mm/min), increased 5 mm/min after tacrolimus. In the controlled study, STT increased by 5 mm/min in 7/10 dogs (14/20 eyes) that received tacrolimus and in none of the 10 dogs that received aqueous carrier alone. Dogs receiving just the aqueous carrier were subsequently treated with tacrolimus, and STT increased 5 mm/min in 9 dogs (18/20 eyes) after administration. CONCLUSIONS: Twice daily administration of 0.02% tacrolimus in aqueous suspension effectively increased tear production in dogs with KCS. Topical tacrolimus is a promising alternative to topical CsA for treatment of KCS and may be beneficial in patients with less than optimal response to topical CsA.