If the rectus muscles are found to be attached to the existing implant, they are isolated and tagged as in an enucleation. If the rectus muscles are not found to be attached to the primary implant, they can usually be found in the fornices, since their check ligaments tend to prevent them from fully retracting into the orbit when released. Identification of the superior, inferior, medial, and lateral rectus muscles is confirmed by feeling for contractions during socket movement and by visual inspection using a 4X loupe. Each muscle is then tagged with 5-0 Vicryl suture. A retrobulbar block is administered through the posterior aspect of the socket and the muscle dissection is completed.
Care is taken to avoid damage to the levator complex.
The socket is then inspected for scarring that may have contributed to the migration of the primary implant, and all such scars are lysed to allow proper placement and to prevent migration of the new implant. Proper sizing of the orbit is essential to avoid complications and to achieve an optimum fit of the implant to both the orbit and the artificial eye. An undersized implant may result in enophthalmos or a deep superior sulcus, and may necessitate weight-increasing modifications to the artificial eye which, in turn, induce lower lid sag and restricted motility. Conversely, an oversized implant increases the risks of wound dehiscence, exposure, infection, and may complicate the coupling of the artificial eye to the motility peg. A set of graduated sizing spheres should be used to properly size the orbit.