Role of central corneal thickness in intraocular pressure changes after corneal refractive surgery

Objective The aim of the study was to assess importance of central corneal thickness (CCT) in the intraocular pressure (IOP) variation after corneal refractive surgery. Patients and methods This prospective, interventional study contains 75 patients who were divided into three equal groups. Group I had undergone femtosecond laser-assisted in-situ keratomileusis (femto-LASIK); Group II had undergone laser in-situ keratomileusis (LASIK); and group III had undergone photorefractive keratectomy (PRK). The evaluated parameters included age, sex, spherical equivalent refraction (preoperative and postoperative), CCT preoperatively and postoperatively and IOP preoperatively and postoperatively at 1, 3, and 6 months by Goldmann applanation tonometry (GAT) and ocular response analyzer. Result The mean CCT reductions were 56.6 ± 34.1, 52.8 ± 25.5, and 40.5 ± 25.9 μm after femto-LASIK, LASIK, and PRK surgery. The mean IOP reductions by GAT were 2.42 ± 1.9, 2.46 ± 2.56, and 1.14 ± 1.31 mmHg after 1 month in femto-LASIK, LASIK, and PRK; however, after 3 months 3.14 ± 1.87, 3.22 ± 2.99, and 2.7 ± 2.23 mmHg after femto-LASIK, LASIK, and PRK. After 6 months the mean IOP reduction was 3.22 ± 1.83, 3.44 ± 2.91, and 2.84 ± 2.32 mmHg after femto-LASIK, LASIK, and PRK. The mean IOPg reduction was 2.53 ± 1.81, 3.19 ± 1.76, and 3.29 ± 1.87 mmHg at 1, 3, and 6 months after femto-LASIK. However, the mean decrease in IOPg was 2.67 ± 2.08, 3.28 ± 1.95, and3.52 ± 1.89 mmHg at 1, 3, and 6 months after LASIK. The mean decrease in IOPg was 1.26 ± 1.98, 2.85 ± 1.98, and 2.98 ± 1.79 mmHg at 1, 3, and 6 months after PRK. IOPcc is not correlated with CCT. Conclusion The IOP by GAT and IOPg reduction after corneal refractive surgery significantly depends on CCT changes, but IOPcc measurements are not associated with CCT.