Biodegradation of nylon loops of intraocular implants in children

In none of the 418 first-stage intraocular implant insertions with intracapsular cataract extractions I have carried out in adults is there any clinical evidence of nylon loop degradation. Although there are no previous reports of clinically observable implant loop degradation, clinically detectable biodegradation was found in eleven eyes of seven children and four adults among the 34 second-stage iris-clip or iridocapsular implants I inserted after aspiration of cataract in children and young adults. The degradation has not produced any uveitis, keratopathy, or instability of the implants in any of these patients. Two children had unilateral glaucoma in the eye containing an iris-clip implant. One of them had dense amblyopia in that eye and the iris-clip implant was removed at the time of trabeculectomy. Scanning electron microscopy of this implant is reported. Active search for nylon particles in the trabeculectomy specimen of the second child has shown the presence of strongly birefringent particles in the trabecular tissue. The possible mechanism of biodegradation of the nylon loops is discussed.