Comparison of Intraocular Pressure Measurements After LASIK Using Goldmann Applanation Tonometry and CorVis ST: A Prospective Clinical Study
DOI:
https://doi.org/10.47363/JORRR/2025(6)222Keywords:
LASIK, Intraocular Pressure, Goldmann Applanation Tonometry, CorVis ST, Central Corneal Thickness, Corneal Biomechanics, Refractive Surgery, GlaucomaAbstract
Background: Accurate measurement of Intraocular Pressure (IOP) is essential for the diagnosis, management, and follow-up of glaucoma. Laser in situ keratomileusis (LASIK) alters corneal thickness and biomechanical properties, which may affect the accuracy of IOP measurements obtained by conventional methods such as Goldmann Applanation Tonometry (GAT). The CorVis ST, a Scheimpflug-based device, has been proposed as a more reliable alternative for assessing IOP after refractive surgery.
Objective: To compare changes in IOP measurements before and after LASIK surgery using Goldmann Applanation Tonometry and CorVis ST, and to evaluate the influence of Central Corneal Thickness (CCT) on these measurements.
Methods: This prospective comparative clinical study included 50 eyes of 50 myopic patients aged 20-40 years who underwent LASIK surgery between February 2024 and June 2025 at Al Baha Health Cluster, Al Baha, Saudi Arabia. IOP was measured preoperatively and two months postoperatively using both GAT and CorVis ST. Central corneal thickness was assessed using Pentacam and CorVis ST. Statistical analysis was performed using SPSS version 16, with significance set at p < 0.05.
Results: Mean preoperative IOP measured by CorVis ST and GAT was 16.02 ± 2.01 mmHg and 16.22 ± 2.30 mmHg, respectively, with no significant difference between methods. Postoperatively, IOP significantly decreased with both devices (p < 0.001). However, GAT showed a greater reduction (11.44 ± 2.02 mmHg) compared with CorVis ST (14.72 ± 1.87 mmHg). Average IOP underestimation after LASIK was approximately 6.5 mmHg with GAT and 1.6 mmHg with CorVis ST. Significant positive correlations were found between CCT and IOP measurements both preoperatively and postoperatively.
Conclusions: CorVis ST demonstrated strong agreement with GAT before LASIK and provided more reliable postoperative IOP measurements. Compared with GAT, CorVis ST was less affected by LASIK-induced corneal changes and showed substantially lower IOP underestimation, making it a preferable tool for postoperative IOP assessment.
