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 thus providing information to permit better and safer IOLs and other ocular implants and procedures to be designed. 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 (A-IOLs). However, despite this renewed interest in IOLs for the correction of presbyopia (as well as myopia, hyperopia, and astigmatism), 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 Principal Investigator are not hampered by the iris and are thus able to provide non-invasive visualization of the entire IOL (optic and haptics) and fully characterize its geometric relationship to surrounding intraocular structures both during accommodation and with accommodation at rest;this information cannot be obtained from the intact eye by any other method. The ultimate goal of this project is to produce a biometric database of the unique information obtained from MRI images of the pseudophakic eye in order to fully characterize IOL placement in the anterior segment. 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 MRI data suggest that it is also closely associated with IOL malposition. We plan to non-invasively grade Soemmering's ring in vivo with MRI and correlate Soemmering's ring development with anterior segment biometry and IOL type, position, tilt, decentration, and accommodative behavior. Successful completion of this project will facilitate the construction of models that allow better traditional, 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. PUBLIC HEALTH RELEVANCE: Cataract surgery is the most common surgery in the world and its frequency will increase as the population ages. In this surgery, the human lens is removed and replaced with an intraocular lens (IOL). It is a safe procedure, but complications do occur and vision after surgery is not always optimal. 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 location inside eye and how this changes depending upon whether one is looking far or near. Thus measurements will be made to better understand IOL location inside the eye and the complications that can occur with cataract surgery. This information will permit better and safer IOLs and other eye implants be designed to improve vision as well as treat eye diseases.