Abstract
Purpose: To assess the accommodation amplitude (AA) pre–post lens capsule refilling using viscous fluids and 3 prototype crosslinked siloxane polymers. Methods: The change in dioptric power of postmortem lenses mounted in a lens stretching device (EVAS) was measured pre/post phaco–ersatz technique. Tissue specimens consisting of the lens, zonules, ciliary body and segmented sclera were subject to 2mm of radial stretching. The dioptric power of the lens was measured in the stretched and unstretched states using a Scheiner–based optical system. After measuring AA in the natural lens, lens extraction was performed through a continuous circular minicapsulorrhexis (0.8 to 1.3mm) by manual lens aspiration combined with phacoemulsification techniques. A miniature valve (MCV) was placed in the capsulorhexis to isolate the capsular bag which was refilled with biocompatible polymers and cured using a visible light source. Experiments were conducted on 11 rhesus, 9 cynomolgus and 2 baboon eyes (age range: 1 to 15 years; postmortem time 1 to 24hrs). 9 eyes were refilled with a 10kcS viscosity trimethyl–terminated polydimethylsiloxane (PDMS), 7 eyes with prototype Polymer #1, 2 eyes with Polymer #2 and 2 eyes with Polymer #3. Results: For a 2mm radial stretch, (AA) was 14.2±3D in natural lenses (n=22); 9.2±3.5D after refilling with PDMS (n=15); 6.9 ±3.2D after refilling with Polymer #1 and 5 ±3.6D post cure (n=7), 13.1± 0.6D after refilling with Polymer #2 and 8.9±2.6D post cure (n=2), 13.4±2D after refilling with Polymer #3 and 8.1±0.07 D post cure (n=2). Varying the viscosity from 5 to 100kcS had no statistical effect on the change in power during stretching. Overfilling the capsular bag was found to decrease the change in power by as much as 9D. Conclusions: Lens refilling using the Phaco–Ersatz procedure and a prototype polymer restored most of the initial accommodation in post–mortem primate lenses mounted in a lens stretcher.