fibrin and Ocular-Hypertension

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.. 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.. 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).. 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.

Topics: Animals; Anterior Chamber; Cataract; Dog Diseases; Dogs; Female; Fibrin; Fibrinolytic Agents; Follow-Up Studies; Glaucoma; Lens Implantation, Intraocular; Male; Ocular Hypertension; Phacoemulsification; Postoperative Period; Random Allocation; Tissue Plasminogen Activator

Hematoxylin and eosin staining of rabbit eyes after YAG laser anterior capsulotomy showed amorphous substances at the anterior chamber angle. The amorphous substances were identified as fibrin by immunohistochemical methods. This finding indicated that the obstruction of aqueous humor flow by fibrin could be responsible for the elevation of intraocular pressure following YAG laser anterior capsulotomy.

Topics: Animals; Anterior Chamber; Fibrin; Immunohistochemistry; Intraocular Pressure; Laser Therapy; Lens Capsule, Crystalline; Ocular Hypertension; Rabbits; Trabecular Meshwork

We report the use of intracameral tissue plasminogen activator to dissolve a fibrin clot occluding a Molteno tube in the immediate postoperative period. This technique is an effective alternative to awaiting clot lysis or reoperation with minimal risk. The only complication was a small, layering hyphema.

Topics: Aged; Blood Coagulation; Cataract Extraction; Female; Fibrin; Fibrinolysis; Glaucoma, Open-Angle; Humans; Lens Subluxation; Ocular Hypertension; Postoperative Complications; Prostheses and Implants; Recombinant Proteins; Silicone Elastomers; Tissue Plasminogen Activator

We performed argon-laser iridotomy on pigmented rabbits and examined histologically the tissue of the anterior chamber angle, the iris, and the ciliary body. After laser iridotomy, 9/10 eyes showed an elevation in transient intraocular pressure. Deposits of blood plasma with fibrin were observed in the tissue of the circumferential anterior chamber angle from eyes enucleated at a period of high intraocular pressure. In the eyes in which ocular pressures returned to the baseline, the quantity of blood plasma was small. In the laser-irradiated iris and iris processes, cells constructing the vessel wall were degenerated, and blood plasma and fibrin exuded. In and around the ciliary body, fibrin was not demonstrated. These observations suggest that argon-laser irradiation to the iris leads to a breakdown of the blood-aqueous barrier mainly in the laser-treated iris, and that deposition of blood plasma with fibrin in the anterior chamber angle tissue may cause transient intraocular pressure elevations after laser iridotomy in rabbits.

Topics: Animals; Anterior Chamber; Aqueous Humor; Blood; Ciliary Body; Fibrin; Iris; Laser Therapy; Ocular Hypertension; Rabbits; Time Factors