Spontaneous Intraocular Lens Dislocation

Similar to the case reported by Zech and coauthors,1 I recently saw a patient who had a spontaneous dislocation of a posterior chamber intraocular lens (IOL) without any trauma; the IOL had been implanted 10 years earlier. The man, born in 1928, was first seen in 1970. The visual acuity was 6/18 in the right eye and 6/36 in the left, with a marked left divergent squint, posterior cortical lens opacities, and severe retinitis pitmentosa with pigment extending to the central retinal arcades. In 1989, extracapsular cataract extraction was performed in the right eye and a 14.0 mm posterior chamber IOL was implanted without complications. One month postoperatively, the man was hit in the region of the eye by his dog's nose but no obvious injury to the eye was seen. A neodymium:YAG (Nd:YAG) laser capsulotomy was performed later the same year. Extracapsular cataract extraction with implantation of a 14.0 mm IOL was performed in the left eye at the end of 1989; it was also uneventful. In both cases, a can-opener capsulotomy was used. An Nd:YAG capsulotomy was performed in the left eye in 1991. Postoperative visual acuity was 6/9 in the right eye and 6/24 in the left, which was amblyopic. The visual field was restricted to 10 degrees in both eyes. The patient was seen in 1997, reporting some deterioration in vision, and was found to have visual acuity of 6/12 in the right eye and less than 6/60 in the left. The left IOL had completely dislocated within the capsular bag into the vitreous, but the retina was flat. The right IOL had partially dislocated superiorly, with zonular dehiscence. The patient was referred to a colleague who removed the dislocated IOL in the capsular bag from each eye and implanted a sutured posterior chamber IOL in both without complications. The patient regained his preoperative acuity of 6/9 in the right eye and 6/18 in the left, with spectacle correction. It appears that a patient with retinitis pigmentosa may have weak zonules. Other than the blow to the region of the right eye by the dog's nose 1 month after surgery in 1989, there was no obvious history of trauma. Roger McGuinness MD, FRCOphth aSydney, Australia