Association of 24-Hour Intraocular Pressure Fluctuation With Corneal Hysteresis and Axial Length in Untreated Chinese Primary Open-Angle Glaucoma Patients

PURPOSE: The purpose of this study was to evaluate the association of 24-hour intraocular pressure (IOP) fluctuation with corneal biomechanics and ocular biometric parameters in Chinese patients with primary open angle glaucoma (POAG) before initial treatment. METHODS: Forty-nine Chinese patients with POAG (98 eyes) were recruited in this study before start of any POAG treatment. The 24-hour IOP was measured with a 2-hour interval by a noncontact tonometer. Corneal biomechanical properties and biometric parameters were measured once during 8 AM to 6 PM before 24-hour IOP measurement. RESULTS: The 24-hour IOP fluctuation was defined as the differences between the peak and trough IOP measurement and was significantly associated with axial length (AL) in the multivariate analysis. The POAG subjects with AL ≤ 26 mm had significantly larger 24-hour IOP fluctuation but lower corneal hysteresis, compared to those with AL > 26 mm. In addition, subgroup analysis showed that high tension glaucoma subjects had larger 24-hour IOP fluctuation and higher corneal resistance factor than patients with normal tension glaucoma. CONCLUSIONS: This study revealed the association of 24-hour IOP fluctuation with office hour corneal biomechanical properties and AL in patients with POAG. Their contributions to IOP fluctuation should be considered in the risk analysis of glaucoma development and progression. TRANSLATIONAL RELEVANCE: Ocular biometric parameters are related with 24-hour IOP fluctuation in patients with POAG, which is potentially helpful in explaining different progression patterns in different types of patients.