Topography-Guided Trans-Epithelial No-Touch Photorefractive Keratectomy for High Irregular Astigmatism After Penetrating Keratoplasty: A Prospective 12-Months Follow-Up

Abstract

Purpose To describe the efficacy and safety of topography-guided trans-epithelial no-touch photorefractive keratectomy (PRK) for the correction of highly irregular astigmatism after penetrating keratoplasty (PK). Patients and Methods A prospective study was conducted on 12 eyes of 12 patients affected by highly irregular astigmatism after PK for keratoconus. Each patient underwent a single-step topography-guided trans-epithelial ablation (CIPTA ® 2 software, iVis Technologies). Corneal topography data as well as uncorrected (UDVA) and corrected distance visual acuity (CDVA) and spherical equivalent (SEQ) were collected preoperatively (T0) and at 1 (T1), 3 (T2) and 12 (T3) months after surgery. Results Mean UDVA and CDVA significantly improved, respectively, from 1.22±0.17 and 0.18±0.03LogMAR at T0 to 0.63±0.17 (CI 95%, P<0.001) and 0.04±0.03LogMAR at T3 (CI 95%, P<0.001). Mean SEQ significantly decreased from −3.75±1.32 to –1.60±1.32D (CI 95%, P<0.02). Mean subjective refractive astigmatism (SRAST) and mean keratometry astigmatism (SimK) significantly decreased, respectively, from 7.83±0.98 and 8.10±1.48D to 2.83±0.98 and 5.29±1.48D (CI 95%, P<0.001). Corneal Morphological Irregularity index (CMI) significantly decreased from 62.76±7.26 µm to 23.24±7.26 µm (CI 95%, P<0.001). Apart from a single episode of graft rejection 5 days after ablation, successfully reverted with topical steroids, no other complications were noted. A mild corneal haze was observed in two eyes (16.7%) at 3 months post-PRK, and no regression was observed at 12 months. Conclusion Our study demonstrates the safety and long-term effectiveness of a trans-epithelial topography-guided ablation in the treatment of post-PK highly irregular astigmatism.

Topography-Guided Transepithelial Photorefractive Keratectomy for the Treatment of Persistent and Visually-Significant Adenoviral Corneal Infiltrates

“…A transepithelial approach allows for elimination of the epithelial thickness variability due to remodeling and refractive outcomes that are more consistent with the predefined refractive target. 21 The one-step topography-guided transepithelial PRK corrects the epithelial and stromal defects, reduces the risk for post-treatment haze, and leads to a significant improvement in visual acuity. 22 , 23 The improvement in visual acuity and quality of vision is related to the correction of both LOAs and HOAs.…”

Combined Topography-Guided Trans-Epithelial PRK and PTK for Recalcitrant Recurrent Corneal Erosions in Lattice Corneal Distrophy

“…Performing an epithelial debridement before treatment may increase the risk of haze and unpredictable refractive results. 8 Furthermore, a wave-front guided treatment could be not best suited for treating this case, since this approach might require a deeper ablation depth and determine the occurrence of higher-order aberrations.…”

“…The Corneal Interactive Programmed Topographic Ablation software (CIPTA ® , iVIS Technologies, Taranto, Italy) determined the volume of ablation as the intersection between the anterior shape detected by the tomographer and the ideal shape determined taking care of the total corneal astigmatism and of the high order of aberrations, by means of a ray tracing process. 8 , 12…”

“… 6 , 7 Furthermore, topography-guided excimer laser treatment has been shown to be a potentially effective technique due to its ability to analyze and localize corneal irregularities and to prevent stromal and epithelial defects as well as haze development, and the final refractive result could be more predictable. 8 …”

Transepithelial Photorefractive Keratectomy—Review

“…Post-keratoplasty eyes subjected to LASIK are at risk of perforation and endothelial cell loss owing to different flap generation and manipulation [ 89 , 90 , 91 ]. Complications in a series by Spadea et al of 12 PKP patients undergoing LASIK included the formation of corneal haze in 2 and graft rejection in 1, which was managed with topical steroids [ 92 ]. The follow-up was short when one considers the fact that the main issues of regression and corneal haze can develop many years postoperatively.…”