Dislocated intraocular lens after biodegradation of fixation loops. A case report

A boy aged 3 years had a Worst Medallion intraocular lens with loops made of nylon 6 implanted in his right eye after aspiration of traumatic cataract. Post-operatively, the eye was irritated and showed increased tendency to secondary membrane formation. The patient was lost to follow-up 3 months post-operatively. He returned 5 years later because of 4 days of pain and redness in his right eye. On examination, the optic part of the intraocular lens was seen to lie free in the anterior chamber. The loops were broken near their insertions in the lens body. The distal ends of the broken loops could not be detected in the pupillary region. No traces of the iris fixation suture were to be seen. The lens was removed and subjected to scanning electron microscopy which revealed extensive biodegradative changes in the 3 loop stumps, the 4th being totally dissolved. The young age of the patient and the chronic inflammation may have had an accelerating effect on the nylon degradation. We conclude that children with eyes implanted with nylon-loop lenses should stay under regular ophthalmological control.