Optimal timing of capsular tension ring implantation: Miyake-Apple video analysis

PURPOSE: To evaluate the appropriate timing for capsular tension ring implantation in cases of zonular weakness either prior to or after lens extraction using Miyake-Apple video analysis. SETTING: John Moran Eye Center, Salt Lake City, Utah, USA. METHODS: Four cadaver eyes were prepared using a standard Miyake-Apple protocol with image capture using digital video recording. After continuous curvilinear capsulorhexis and hydrodissection/ viscodissection were performed, 2 eyes had early capsular tension ring implantation (CTR) and 2 eyes had CTR implantation after lens extraction. The 12.3 mm CTR was implanted in all eyes. Capsular bag torque and displacement, zonular elongation and stress, and ease of CTR placement were evaluated in each eye. RESULTS: Early CTR implantation resulted in significantly increased capsular torque and displacement of up to 4.0 mm compared to insertion in an empty capsular bag. There was significant zonular elongation and tension during early placement. CONCLUSION: In terms of minimizing further zonular stress and damage and capsular destabilization, the ideal timing for CTR placement is after lens extraction and decompression of the capsular bag.