MORPHOMETRIC CORNEAL REPAIR PATTERNS AFTER DIFFERENT METHODS OF SURFACE PHOTOABLATION FOR MYOPIA: CORRELATION ANALYSIS AND CLUSTERING

To analyze morphometric corneal repair patterns after different methods of surface photoablation for myopia using correlation analysis and clustering.

Multicenter clinical study (Ukraine)

A prospective study included 255 patients (510 eyes) who underwent PRK, transepithelial PRK (tPRK), or LASEK. Epithelial healing time was evaluated by slit-lamp biomicroscopy with fluorescein staining, epithelial and stromal thickness (AS-OCT), Corneal Irregularity Measurement (CIM), obtained from a Placido-disk topographer (ZEISS ATLAS with Pathfinder analysis, Carl Zeiss Meditec AG, Jena, Germany), UDVA were assessed along with postoperative complications (delayed epithelialization ≥7 days, epithelial hyperplasia (>20 µm), stromal edema (>20 µm), pathological CIM, subepithelial haze) over 3 months. Pearson coefficient (r) was used to determine correlations between haze and other morphological characteristics (delayed re-epithelialization, epithelial hyperplasia, stromal edema and pathological CIM). K-means clustering (k=2) was performed in Principal Component Analysis (PCA) space to identify reparation patterns.

Stromal edema occurred in 28% after PRK, 19% after LASEK, and 14% after tPRK. Epithelial healing delay ≥7 days was found in 16%, 13%, and 10%, respectively. Pathological CIM was observed in 22%, 20%, and 15%, while haze occurred in 9%, 7%, and 4%. Epithelial hyperplasia occurred in 23% after LASEK, 14% after PRK, and 12% after tPRK. Subepithelial haze was observed in 9% after PRK, 7% after LASEK, and 4% after tPRK. Haze showed strong correlations with stromal edema (r=0.96) and delayed epithelialization (r=0.93) according to correlation analysis. Cluster analysis revealed pathological profiles in 16.5% (PRK), 14.7% (LASEK), and 10.6% (tPRK), identifying subgroups with abnormal reparative patterns.