Morphology and immunohistochemistry of spontaneous chronic corneal epithelial defects (SCCED) in dogs.

PURPOSE: To determine the morphologic features of the epithelium and extracellular matrix in spontaneous chronic corneal epithelial defects (SCCED) in dogs. METHODS: Forty-eight superficial keratectomy specimens were obtained after confirmation of the presence of a superficial corneal erosion for longer than 3 weeks with no discernible underlying cause. Histologic samples were examined by light microscopy, scanning electron microscopy, and transmission electron microscopy. Immunolocalization of laminin, collagen IV, fibronectin, and collagen VII was performed. RESULTS: Epithelial cells adjacent to the defect were poorly attached to the underlying extracellular matrix. A prominent superficial stromal hyaline acellular zone composed of collagen fibrils in the area of the erosion was present in most specimens. Samples exhibited a varying degree of fibroplasia, vascularization, and leukocytic infiltrate. Laminin, collagen IV, and collagen VII were usually either not present or were present only in discontinuous segments on the surface of the erosion. Fibronectin usually coated the surface of the erosion, either as a continuous sheet or in discontinuous segments. Transmission electron microscopy of 15 samples revealed that the basement membrane was either absent in the area of the erosion or was present only in discontinuous segments. Scanning electron microscopy of eight of nine samples confirmed the absence of continuous basement membrane. Epithelial and extracellular matrix components in the peripheral cornea appeared normal. CONCLUSIONS: Most canine patients with spontaneous chronic corneal epithelial defects do not have a normal basement membrane structure in the region of the epithelial defect and have other abnormalities in the subjacent extracellular matrix that may reflect a part of the underlying pathophysiology of chronic and recurrent erosions.

Effect of intracameral administration of carbachol on the postoperative increase in intraocular pressure in dogs undergoing cataract extraction.

OBJECTIVE: To determine whether intracameral injection of carbachol at the completion of phacoemulsification in dogs would prevent the increase in intraocular pressure (i.o.p) that can develop during the first 24 hours after surgery. DESIGN: Randomized controlled trial. ANIMALS: 32 adult dogs undergoing elective unilateral or bilateral phacoemulsification. PROCEDURE: Dogs were randomly assigned to 1 of 4 groups with 8 dogs/group: phacoemulsification and intracameral administration of 0.5 ml of 0.01% carbachol at the end of surgery; phacoemulsification, intraocular lens implantation, and intracameral administration of 0.5 ml of 0.01% carbachol; phacoemulsification and intracameral administration of 0.5 ml of balanced salt solution; and phacoemulsification, intraocular lens implantation, and intracameral administration of 0.5 ml of balanced salt solution. Intraocular pressure was measured at 3 and 6 hours and the morning after surgery. Aqueous flare was also measured 6 hours and the morning after surgery. RESULTS: None of the dogs treated with carbachol developed postoperative ocular hypertension (i.e., IOP > 27 mm of Hg), whereas 12 of 16 control dogs had ocular hypertension 3 hours after surgery. Intraocular pressure 3 hours after surgery was not significantly associated with phacoemulsification time or phacoemulsification power or with whether the dog received an intraocular lens implant. Severity of aqueous flare was similar for treated and control dogs. CLINICAL IMPLICATIONS: Results suggested that intracameral administration of 0.01% carbachol at the end of surgery was a safe and efficacious method of preventing the postoperative increase in IOP associated with phacoemulsification in dogs.

Stellate rhytidectomy: superior entropion repair in a dog with excessive facial skin.

A four-year-old Chinese shar pei was presented for entropion repair that had not been corrected adequately with two prior Hotz-Celsus procedures. The primary cause for the failure was the weight of the excessive, superior facial folds often found in this breed. A new technique is presented to measure and remove these folds in a stellate pattern by following natural stress lines, thus effecting surgical repair of the superior lid entropion.