Abstract
Abstract: :
Purpose: To measure the strength of the lens capsule after capsulorhexis. Methods: Capsulorhexis measuring 1 to 3mm in diameter were made in either the central or peripheral region of 30 Eye Bank and 32 rabbit eyes. A specialized instrument was built in order to stretch the capsulorhexis at a constant rate. The capsulorhexis was stretched until rupture, as the applied load (in grams) was recorded by a data acquisition program. The applied load as a function of displacement was found for each experiment. From this, the maximum strain was calculated. Results: The average value for the load for eye bank eyes was 26±20mN for central and 53±21mN for peripheral capsulorhexis. The average value for the strain for eye bank eyes was 50±18% for central and 63±17% for peripheral capsulorhexis. The average value for the load for rabbit eyes was 20±15mN for central and 14±9mN for peripheral capsulorhexis. The average value for the strain for rabbit eyes was 38±13% for central and 30±7% for peripheral capsulorhexis. Conclusion: The load that was applied to the capsulorhexis just before rupture was greater for a peripheral capsulorhexis than a central capsulorhexis in eye bank eyes (P=0.00164). The strain was also greater for a peripheral capsulorhexis as compared to a central (P=0.0516). For the rabbit eyes, the difference between maximum load and strain in the peripheral versus central regions was statistically insignificant. These patterns of applied stress were consistent with known capsule thickness profiles. Supported in part by the Florida Lions Eye Bank; Australian Cooperative Research Centre (CRC) Scheme, CRC for Eye Research and Technology, Sydney; Henri and Flore Lesieur Foundation, Palm Beach, FL.
Keywords: 338 cataract • 304 accommodation