Effect of expandable full-size intraocular lenses on lens centration and capsule opacification in rabbits

Purpose: To study the effects of expandable, hydrogel, full-size lenses (FS Ls) on lens centration and posterior capsule opacification (PCO) in the rab bit model. Setting: Center for Intraocular Lens Research, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Methods: Small FSLs designed for human eyes were implanted unilaterally in 20 rabbit eyes. Lens centration and PCO in these eyes were compared with th ose in eyes with conventional poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) or aphakia in the fellow eyes. In a second experiment, medium -size or targe FSLs designed for rabbit eyes were implanted in 20 rabbit ey es and the results compared with those in eyes with conventional PMMA IOLs. Slitlamp examination of all eyes was performed regularly, after enucleatio n, gross inspection and microscopic-studies were performed. Results: Decentration of FSLs occurred in the presence of an anterior capsu le tear or very large capsulorhexis. Posterior capsule opacification develo ped only at sites where the implanted lens was not in contact with the caps ule. Aphakic eyes and looped IOLs developed Soemmering's rings peripherally In eyes with small FSLs, PCO developed between the lens and the center of the posterior capsule, whereas in eyes with large FSLs, only small amounts of central PCO developed. Retained high-viscosity viscoelastic material had no effect on PCO development. Conclusions: Complete refilling of the capsular bag by a full-size IOL was associated with excellent centration and only a small degree of PCO. Elasti c lenses may thus serve as a starting point for the development of an artif icial lens with accommodative function.