Correction of high myopia in patients with stabilized keratoconus using implantation of additional posterior chamber phakic lenses

Purpose. To examine the effectiveness and safety of correction of high myopia in patients with stabilized keratoconus using implantation of additional posterior chamber phakic lenses (PIOLs). Material and methods. This study included the results of 27 operations for PIOL implantation in patients with high myopia and myopic astigmatism (sphero-equivalent (SE) –12.63±4.25 D, astigmatism –2.13±1.24 D) with thin corneas with a concomitant diagnosis keratoconus stage 1–2 (after treatment with corneal collagen crosslinking), as well as in patients with the so-called «form frust» of keratoconus. In all cases, sulcus-to-sulcus diameter (STS) was evaluated to determine the lens size. PIOL (IPCL V2.0, Caregroup Sight Solutions, India) was used in all surgeries. The data analyzed were pre- and postoperative visometry values, biomicroscopy, OCT of the anterior segment of the eye – determination of the distance from the posterior surface of the lens to the anterior capsule of the lens (Vault), corneal curvature, number of endothelial cells, intraocular pressure (IOP). Controls were performed 1 day, 3, 6 and 12 months after surgery. Results. No intraoperative complications were observed. In the postoperative period, during the specified time intervals, observations of anterior capsular cataract were not recorded in any case. One patient (2 eyes) experienced a transient increase in IOP due to glucocorticoids application in the postoperative period; pupillary block due to the presence of numerous holes in the PIOL was not observed. The number of endothelial cells was non-significantly reduced 1 year after surgery by 7.01±2.12% (p=0.71). All patients had high visual acuity (UCVA 0.86±0.11). The mean Vault was 527.5±40.27 mm (range 460–600 µm) and IOP 11.7±2.08 mm Hg. Conclusion. Implantation of PIOL in patients with stabilized and «form frust» keratoconus allows safe and effective correction of high degrees of myopia and astigmatism. This type of surgery is especially relevant in cases where it is impossible to use glasses and contact correction. Key words: cornea, keratoconus, PIOL, implantation