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Posterior chamber phakic IOL safe for hyperopes; does not increase BCVA
J Cataract Refract Surg. 2009;35(2):248-255.
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A new posterior chamber phakic IOL offered stable, predictable refractive outcomes in hyperopes.
The prospective study included 40 eyes of 25 patients with a mean age of 32 years.
Patients were implanted with the PRL phakic refractive IOL (Medennium), a silicone lens that rests on the zonules and floats in the posterior chamber.
Inclusion criteria were 20- to 45-year-olds, hyperopia correlated with phakic IOL power, central anterior chamber depth of at least 3 mm, endothelial cell density more than 2,000 cells/mm2 and IOP less than 25 mm Hg.
Data showed mean best corrected visual acuity significantly diminished at 3 months and stable at 1 year. Also at 1 year, all eyes were within 1 D of target refraction and 35 eyes (87.5%) were within 0.5 D.
Mean endothelial cell loss was 4.6% at 3 months and 3.8% at 1 year. Mean IOP remained stable between follow-ups. Complications included postoperative pupillary block (seven eyes), severe glare (two eyes), and unexpected myopia and discomfort (one eye). Data showed no IOL-induced glaucoma or cataract.
“No gain in BCVA is expected after PRL implantation in hyperopic eyes,” the authors said. “However, the correlation between the visual acuity outcome and patient satisfaction must be evaluated in a future study with administration of a patient questionnaire.”
Phakic IOLs perform less well in high hyperopia than in high myopia. The major problem is the smaller anterior segment with reduced anterior chamber depth. This results in a significant number of patients where the surgery cannot be performed. In addition, the complication rate when a lens implant can be placed in the highly hyperopic eye is much higher than that observed in the high myope. In this series the cumulative complication rate was 37.5%, with a 17.5% incidence of pupillary block, which is a sight-threatening complication. Finally, with age the natural lens continues to enlarge in its anterior/posterior dimension, further crowding an already narrow space. Late complications are almost inevitable. Most surgeons, including myself, prefer refractive lens exchange in the highly hyperopic eye. The outcomes are excellent with high patient satisfaction, the risk of acute narrow angle glaucoma is mitigated, and the retinal detachment risk present in the high myope is absent.
– Richard L. Lindstrom, MD
OSN Chief Medical Editor