Long-term outcomes of posterior chamber phakic intraocular lens implantation in keratoconus

Background: In this retrospective observational case series study, the aim was to evaluate the long-term safety, efficacy, stability and predictability of posterior chamber phakic intraocular lens (pIOL) implantation to correct myopia and myopic astigmatism associated with keratoconus. Methods: Uncorrected distance visual acuity (UDVA), best spectacle-corrected distance visual acuity (BSCDVA), refraction and adverse effects were evaluated in 23 keratoconic eyes of 13 patients after five years with Visian ICMV4 pIOL (STAAR Surgical) Results: The mean pre-operative spherical equivalent and cylinder changed from -5.35 +/- 2.82 D and -3.14 +/- 1.58 D to -0.78 +/- 1.31 D and -1.56 +/- 1.53 D, respectively, five years post-operatively. Before the surgery the mean Snellen decimal BSCDVA was 0.60 +/- 0.20. The mean UDVA and BSCDVA changed to 0.74 +/- 0.22 and 0.88 +/- 0.16, respectively. A total of 82.5 per cent of eyes achieved 6/12 or better UDVA post-operatively. The mean safety and efficacy indices were respectively, 1.47 +/- 0.32 and 1.24 +/- 0.34. No eye lost a line of visual acuity and 19 eyes gained one or more lines. An endothelial cell loss of 7.88 per cent occurred. No significant changes were seen in intraocular pressure, steep, flat and mean keratometry. The crystalline lens was clear. Conclusion: The clinical outcomes of the current study demonstrate the safety, efficacy and predictability of the implantable collamer lens (toric and non-toric) in the correction of myopia and myopic astigmatism associated with keratoconus. The patients' refractions achieved early stability and remained stable during the course of the study.