[Piggyback lens implantation for anisometropia in pseudophakic eyes]

Long standing pseudophakia or previous laser capsulotomy make lens exchange for anisometropia or incorrect target refraction difficult. Piggyback lens implantation might be a less traumatic surgical alternative.

Eight patients had a secondary posterior chamber lens implant (PMMA) into the ciliary sulcus. Lens power was estimated by the preoperative refraction according to the refractive vergence formula and was controlled intraoperatively by an automatic refractometer. Surgical access minimized preoperative astigmatism.

All patients had disturbing anisometropia of 4.57+/-2.86 D and had undergone cataract surgery 1-13 years previously. Piggyback lens implantation was combined with surgical aspiration of the secondary cataract in three patients. Due to recurrent PVR retinal detachment, one patient received a silicon oil refilling procedure and piggyback lens implantation. The preoperative spherical equivalent was -3.34+/-4.9 D. Mean follow up time was 16.6 months. Postoperative anisometropia was reduced to 1.1+/-1.01 D. The mean absolute deviation from target refraction was 0+/-0.92 D. Elevated IOP or secondary cataract formation in the lens interface were not observed. One patient developed pigment dispersion.

Secondary piggyback lens implantation into the ciliary sulcus in front of an existing posterior chamber lens is a safe and effective refractive surgical procedure for special cases with predictable refraction.