Orbital volume augmentation with adjustable prefabricated methylmethacrylate subperiosteal implants. Prefabricated right and left subperiosteal implants were used in nine anophthalmic sockets to correct superior sulcus deformities. The advantages of these implants include increased stability, easy insertion under direct visualization and the possibility of easy retrieval if necessary, and custom modification for volume and shape intraoperatively, with the addition of methylmethacrylate. There were no extrusions, implant migrations, or infections. Complications included mild undercorrection, upper eyelid blepharoptosis, and transient ectropion. 