Simulated zonular tension analysis in the presence of zonular disinsertion

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Purpose: To analyze and understand the zonular tension and distribution of forces in the presence of zonular disinsertion in a model simulation with and without a capsular tension ring (CTR). Methods: This study was conducted at Complejo Hospitalario Universitario Albacete, University of Castilla La Mancha, Spain. Twelve load cells were arranged in a circular fashion to simulate the 360 degrees of zonulae in the eye. An elastic band was prestretched in a uniform and radial manner in 12 directions. Force measurements were taken using 12 load cells, uniformly arranged at 30° spacing around the elastic band. Tension was measured at each cell, before and after the simulated zonulardisinsertion. Every clock hour of zonular disinsertion was cycled through all 12 load cells. The tension was evaluated for zonular disinsertion ranging from 0 to 5 clock hours (0° to 150°) with and without a CTR. Results: An increase in zonular tension was recorded in the load cells adjacent to the segments of zonular disinsertion. As the zonular disinsertion progressed, opposing forces could no longer cancel each other out, leading to a displacement of thecomplex. The use of a CTR redistributed the forces, providing better centration in the presence of zonulolysis. Conclusion: This study visualizes the distribution of forces and displacement of the capsular bag complex in the presence of zonular disinsertion and demonstrates a significant increase in zonular tension in the areas adjacent to the segment of zonular disinsertion. The use of a CTR managed to redistribute the tension over the remaining zonulae, maintaining better centration in the presence of zonulolysis. The knowledge of this behavior can help surgeons tackle clinically significant zonular disinsertion.