Angle-supported phakic intraocular lenses in eyes with keratoconus and myopia

To evaluate the visual results and complications of angle-supported phakic intraocular lenses (IOLs) to correct myopia associated with early-stage keratoconus.

Private practice, Siena, Italy.

In a prospective noncomparative single-surgeon interventional case series, outcomes in 12 consecutive eyes of 8 patients with stage I to II keratoconus, myopia from -6.50 to -14.00 diopters (D), and astigmatism from -1.00 to -5.00 D were analyzed after the implantation of angle-supported phakic IOLs (ZSAL-4, Morcher). The minimum follow-up was 12 months. Implantation was performed through a sclerocorneal 5.5 mm x 3.0 mm tunnel along the steepest meridian, after which a surgical basal iridectomy was created.

The spherical error in all cases was corrected within +/-1.00 D. Astigmatism magnitude did not significantly improve. The uncorrected visual acuity (UCVA) was 20/40 or better in all cases. The best spectacle-corrected visual acuity (BSCVA) was equal or improved in all cases. The safety index (postoperative BSCVA/preoperative BSCVA) was 1.18; the efficacy index (postoperative UCVA/preoperative BSCVA) was 0.77. Three eyes had significant halos that improved considerably over 3 months. Spectacles were permanently used by 1 patient (2 eyes in the study) and only for driving by 5 patients. Complications were limited to 3 cases of mild pupil ovalization and 1 case of IOL rotation. Endothelial loss at 12 months was 7.2%.

Implantation of angle-supported phakic IOLs to correct myopia in patients with keratoconus stage I to II was an effective procedure. Although astigmatism did not improve by the creation of the incision, it was well tolerated by most patients. Long-term endothelial safety must be assessed.