[Elasticity of capsulorhexis in the animal model]

A special caliper was designed to determine the stretching capacity of a circular capsulorhexis allowing measurements in 0.02 mm increments. A small capsulorhexis 4.5-6.0 mm in diameter could be stretched 2.7 times; a large capsulorhexis 6.5-8.0 mm in diameter was stretched 2.6 times the original diameter. A smooth circular capsulorhexis is very strong and stabile but also has significant stretching capacity. In a small capsulorhexis, there is the danger that zonular fiber defects or posterior capsular rupture may occur during manual expression, of the nucleus. A large capsulorhexis is more suitable for manual nucleus delivery.