Modification of the scleral openings to reduce tissue breakdown and exposure after hydroxyapatite implantations

We compared the incidence of exposure of the hydroxyapatite implant after evisceration according to the position of scleral windows which allow rapid fibrovascularization into the implant. Three patients (10%) developed tissue breakdown and exposure of the hydroxyapatite, out of 30 patients who had external scleral windows located in a position just anterior to the insertion of each of the rectus muscles, whereas no patient developed exposure, out of 24 patients who had internal scleral windows located in a position just position just posterior to the insertion of each of the rectus muscles. Internal windows sealed with rectus muscles could prevent direct contact between implant and the overlying Tenon's capsule and conjunctiva. These findings seem to indicate that the rough spicular surface of the hydroxyapatite irritates and erodes the overlying Tenon's capsule and conjunctiva.