The argument against imbricating the rectus muscles over spherical orbital implants after enucleation.

Upper eyelid ptoses with migrated spherical implants resulting from imbrication of the rectus muscles over the implants after enucleation appears to constitute a syndrome. Traditionally shaped artificial eyes cannot reduce this type of ptosis. Spherical implants 18 mm in diameter do not fill Tenon's space. Imbricated muscles slip off the sphere, usually to the inferior nasal side. The sphere is displaced into the superior temporal quadrant of Tenon's space. A rolling motion is imparted to all tissues. The superior fornix and upper lid are pulled forward and downward. The inferior fornix is stretched into a rounded trough. The lower eyelid is pulled downward and backward. There is little motility to move the artificial eye. There are several better alternative types of surgery, some involving buried quasi-integrated muscle cone implants. More eye fitters will now fit these implants properly because of the educational efforts of the American Society of Ocularists. Two of those are most favored by the author because the surgical methods of their implantations do not contribute to ptosis and the resulting motility and general cosmesis are typically very good to excellent. In the order of preference they are: 18 or 16 mm diameter acrylic spheres in evisceration. The quasi-integrated implant which has become known is the Iowa Implant, specifically designed for imbrication of the rectus muscles after enucleation.