MRI Biometry of the Pseudophakic Cadaver Eye

DESCRIPTION (provided by applicant): Presbyopia is the loss of accommodation with age and industry efforts to provide surgical correction for presbyopia are vigorously underway as the potential market for such a product is substantial. Strategies include lens refilling, scleral treatments, and, most notably, the development of accommodating intraocular lenses (IOLs). However, despite this renewed interest in IOLs for the correction of presbyopia (as well as myopia, hyperopia, and astigmatism), results have been disappointing and many questions remain regarding the optic and haptic sizing and post-operative positional stability, development of Soemmering's ring and posterior capsule opacification (PCO), power calculations, and adverse effects of these and even established IOL designs. The high-resolution MRI techniques developed by the PI are not hampered by the iris and are thus able to provide non-invasive in-situ visualization of the entire IOL (optic and haptics) and its geometric relationship to surrounding intraocular structures; this information cannot be obtained by any other method. The ultimate goal of this study is to produce a biometric database of the unique information obtained from MRI images of both phakic and pseudophakic cadaver globes in order to fully characterize IOL placement in the anterior segment and to provide much needed calibration algorithms between our existing in vivo MRI biometry and cadaver biometry, since cadaver studies are routinely used in IOL design. Moreover, posterior capsule opacification is a common complication of cataract surgery that decreases visual acuity, has been correlated with IOL tilt and decentration, and is of particular concern with new IOL designs. Soemmering's ring, develops after virtually every IOL implantation, is a direct precursor to PCO, is associated with other complications including pupillary block glaucoma, and our preliminary data suggest that it is also closely associated with IOL malposition. We plan to develop methods of non-invasively grading Soemmering's ring in vitro with MRI and correlating Soemmering's ring in the pseudophakic cadaver globe with anterior segment biometry and IOL type, position, tilt, and decentration. Successful completion of this project will facilitate the construction of models that allow better pseudophakic, phakic, and accommodating IOL designs as well as other methods of presbyopia correction to be simulated and developed. Moreover, it will facilitate the construction of refined algorithms for preoperative IOL power calculations and improve our understanding of post-operative complications of IOL surgery. Cataract surgery is a common procedure that results in removal of the human lens and its replacement with an intraocular lens (IOL). It is a safe procedure, but complications do occur. Many new IOLs are being designed to further improve vision after cataract surgery; however, concerns exist regarding both the safety and effectiveness of these new designs. Magnetic resonance imaging has the unique ability to fully show the IOL position in the intact eye and will be used to study cadaver globes with IOLs in order to better understand the complications that can occur after IOL implantation and also to permit better and safer IOLs to be designed.