Validation of IVCM In Measuring Sub-Basal Nerve Plexus and Keratocyte Cell Density in Corneal Wound Healing

Abstract

Introduction: This study aimed to evaluate the reliability measurement of corneal stromal thickness, sub-basal nerve plexus (SBNP) and keratocyte cell density (KCD) in laser refractive surgery patients. Methods: 120 eyes of 60 participants were recruited and both right and left eyes of the myopic subjects were measured separately. Cornea stromal thickness were measured based on the cellular morphology that differs between each corneal layer. Measurement of SBNP and KCD were done using in-vivo confocal microscopy (IVCM) using corneal stromal thickness as reference. Corneal nerve parameters measured includes nerve fiber density (NFD), nerve branch Density (NBD) and nerve fiber length (NFL) while KCD were measured based the amount per area, depending on the region of interest. All images were captured and processed using ImageJTM Software and NeuronJ. All data were expressed in mean and standard deviation. Statistical analyses were performed using Predictive analytics software. P < 0.05 was set as the level of significance. Intra- and inter-observer intraclass correlation analysis were done to evaluate reliability of measurement in corneal stromal thickness, SBNP and KCD. Results: This study found no significant difference between measurements for corneal stromal thickness, SBNP and KCD measured. (All P > 0.05). Intraclass correlation analysis showed both intra- and inter-observer performance were approximately consistent and reliable (All r > 0.90, P > 0.05). Conclusion: Measurement of corneal stromal thickness, SBNP and KCD using IVCM is valid and reliable.