TOPOGRAPHY-GUIDED PRK FOR IRREGULAR ASTIGMATISM CORRECTION IN KERATOCONUS PATIENTS

Abstract

Purpose. To evaluate the efficacy of topography-guided photorefractive keratectomy (PRK) performed using the MicroScan Visum excimer laser (Optosystems, Russia) after intrastromal corneal ring segment (ICRS) implantation and collagen cross-linking (CXL) in the management of keratoconus.Material and methods. Prospective, non-comparative analysis of case series comprised 42 eyes of 40 keratoconic patients (23 male, 17 female). All patients had the ICRS implantation and collagen cross-linking to stabilize the ectasia. The trans-epithelial topography-guided PRK was performed using the MicroScan Visum excimer laser (Optosystems, Russia). The outcome measurements included: UCVA, BCVA, keratotopography («TMS-4», Tomey), Scheimpflug tomography (Pentacam, Oculus), confocal microscopy (Confoscan 4, Nidek). Postoperative assessments were performed at 1, 3, 6 and 12 months.Results. Six months after the topography-guided PRK there was noted a significant improvement in UCVA from 0.08±0.04 to 0.52±0.18 and BCVA from 0.46±0.15 to 0.64±0.19. No eyes lost lines of BCVA. 88.8% of eyes gained 1 or more line of BCVA and 31.2% of eyes gained 2 lines of CDVA.Conclusions. The efficacy of the topography-guided PRK using the MicroScan Visum excimer laser in keratoconic patients after ICRS implantation and collagen cross-linking is confirmed by an improvement of uncorrected and best corrected visual acuity. The safety is reflected in the stability of an elevation of the posterior corneal surface and a lack of formation of a clinically significant degree of fibroplasia.

Keywords

• topograhy-guided prk
• irregular astigmatism
• keratoconus