Effects of phacoemulsification and extracapsular lens removal on corneal thickness and endothelial cell density in the dog.

Twenty-one dogs were used to study the effects of phacoemulsification and extracapsular lens removal on corneal endothelium and corneal thickness. Specular microscopy revealed preoperative cell morphology and cell densities similar to man. After surgery endothelial cell counts significantly decreased 22% (central) and 13% (periphery) with phacoemulsification and 34% (central) and 31% (periphery) with extracapsular lens removal. Corneal thickness increased with both procedures. Endothelial cell pathology included cellular enlargement, increased pleomorphism, and focal cellular degeneration. Phacoemulsification time did not correlate with the degree of cell loss. Dog corneal endothelium responds to surgical trauma in a manner similar to man and maintains a functional monolayer via cellular enlargement and migration. The dog, therefore, represents a good animal model for the study of corneal endothelial disease in man. Invest Ophthalmol Vis Sci 24:227-236, 1983 With the advent of ultrasonic instrumentation for the removal of cataractous lenses, cataract surgery in man has been significantly modified. 1 While many advantages are derived from phacoemulsification, potential degeneration or destruction of the corneal endothelium is a significant problem. Corneal endothelial cell lesions may be associated with heat produced at the tip of the ultrasonic probe, irrigation of the anterior chamber with a variety of irrigation solutions, vibration of the ultrasonic probe, mechanical damage from lens cortical and nuclear material, and instrumentation. 2 " 4 Resulting corneal edema may be severe. Endothelial cell loss following lens removal is variable in man. Phacoemulsification in man results in endothelial cell loss commonly ranging from 18 to 34%, 5 ~ 6 while intracapsular lens extraction cell loss may range from 12 to 15%. 6 " 7 Additional procedures such as intraocular lens implantation result in additional endothelial cell losses. 5 " 7