The ideal ocular prosthesis - Analysis of prosthetic volume

Purpose: An ocular prosthesis should complement the volume of the intracona l implant to achieve complete replacement of the volume that is removed by enucleation. This study investigates the limitations on the prosthetic volu me in achieving this goal. Methods: Prosthetic volume and thickness were measured in 70 patients who u nderwent enucleation. Patients in group 1 (n = 17) were adults enucleated i n childhood, and patients in group 2 (n = 53) were enucleated as adults. Cl inical problems after enucleation were documented to determine problems pot entially related to prosthetic volume. Results: None of the ocular prostheses in this patient series was greater i n volume than 4.2 ml (range, 0.75-4.2 ml). The average prosthetic volume fo r patients with implant diameters of 14 mm to 22 mm was 2.2 ml. A prostheti c volume greater than or equal to 1.8 mi provided an anterior to posterior dimension of 7 mm. Anterior malposition of the implant and the presence of severe socket contraction were noted in patients with the smallest and the thinnest prostheses. Zn group 2, larger prostheses were associated with pto sis and lower eyelid laxity (p < 0.05: p < 0.01). Conclusions: One should not depend on the ocular prosthesis to supply more than 4.2 ml of volume in the anterior compartment of the socket. Adult pati ents with normal bony development, noncontracted sockets, and an average ax ial length should not receive implant sizes <20 mm, if one intends to achie ve complete replacement of the volume removed by enucleation. Children shou ld receive the largest implant possible.