Purpose: To report the occurrence of subluxation of suture-fixated posterior chamber (PC) intraocular lenses (IOL) and elucidate the mechanisms involved.
Design: Prospective clinicopathologic study.
Participants: A single 10-0 Prolene suture explanted from a patient who experienced subluxation of his PC-IOL, 11.5 years after placement. Furthermore, multiple 10-0 Prolene sutures and PC-IOLs used for iris fixation were studied as controls.
Methods: Scanning electron microscopy (SEM) was used to analyze the surface of the explanted suture. In addition, randomly selected 10-0 Prolene sutures cut with Vannas scissors and cut with the positioning holes of a randomly selected PC-IOL identical to that implanted in the patient's eye were examined as controls. Finally, the positioning holes of several randomly selected, iris-fixated PC-IOLs were studied using SEM with particular attention to surface quality and edge finish.
Main outcome measures: Presence of any signs of suture degradation, the character of the cut edge of the suture, as well as the characteristics of the positioning holes of the PC-IOLs.
Results: Scanning electron microscopy of the explanted suture revealed sharply cut edges, without significant degradation of the suture, and no intact loop. Scanning electron microscopy of the control suture cut with a PC-IOL demonstrated a similarly cut edge. The positioning holes of the examined PC-IOLs had a sharp edge, and some also had an imperfect finish.
Conclusion: We conclude that the surface properties of the positioning holes lead to cutting of the suture, and subsequent subluxation of the PC-IOL.