Effects of intracameral administration of α-chymotrypsin on intracapsular lens extraction and postoperative outcome in clinically normal dogs

Abstract

To assess the intraoperative and postoperative clinical effects and histologic effects of intracameral administration of α-chymotrypsin in clinically normal dogs undergoing standard intracapsular lens extraction (ICLE). 6 young adult male dogs without evidence of systemic or ocular disease. All dogs underwent bilateral ICLE 7 minutes following injection of 75 U of α-chymotrypsin or an identical volume (0.5 mL) of a commercially available balanced saline solution (BSS) into the posterior chamber of the eye. Ease of lens extraction was subjectively assessed and intraoperative intraocular hemorrhage and fibrin accumulation scored. For 27 days after surgery, ocular hyperemia and discharge, chemosis, corneal edema, hyphema, and aqueous flare were scored, and intraocular pressure (IOP) was measured. Thirty days after surgery, histologic evidence of anterior synechia, collapse of and inflammation within the iridocorneal angle, and iritis were scored. In 5 of 6 dogs, the surgeon was able to correctly identify the eye treated with α-chymotrypsin on the basis of ease of lens extraction. Mean intraoperative intraocular hemorrhage and fibrin scores for BSS-treated eyes were significantly higher than for α-chymotrypsin-treated eyes. Postoperatively, there were no significant differences between treatments for any clinical variables, including IOP Histologic scores were not significantly different between treatments for any variable. Vision was lost as a result of glaucoma in 1 α-chymotrypsin-treated eye and 1 BSS-treated eye. Intracameral administration of 75 U of α-chymotrypsin 7 minutes before ICLE facilitated lensectomy without apparent adverse effects in clinically normal dogs.