Effect of axial length on diurnal IOP in cataract patients without glaucoma

To evaluate the effect of ocular biometrics on intraocular pressure (IOP) and diurnal IOP fluctuation in nonglaucomatous subjects.

We examined 115 subjects from May to December 2007 in Kangbuk Samsung Hospital, Seoul, Korea. Intraocular pressure was measured with a Goldmann applanation tonometer in habitual positions every 2 hours from 9 am to 11 pm. Ocular biometric values including central corneal thickness, central corneal power, axial length, anterior chamber depth, and lens thickness were measured using an ultrasound biometer and keratometer and the refractive state was determined.

Two hundred fourteen eyes of 115 patients were included in this study; the mean (±SD) IOP of all eyes was 12.33 (±2.55) mmHg. The mean (±SD) diurnal IOP fluctuation was 2.72 (±1.43) mmHg. Central corneal thickness was positively correlated with the mean IOP (Pearson correlation, r = 0.217, p = 0.002); however, there was no relationship between central corneal thickness and the diurnal IOP fluctuation. Axial length was not related to the mean IOP (Pearson correlation, r = 0.049, p = 0.476) and the diurnal IOP fluctuation (Pearson correlation, r = 0.058, p = 0.395). The mean IOP or diurnal IOP fluctuation was not related to any of the following values: central corneal power, anterior chamber depth, refractive error, lens thickness, or vitreous chamber depth.

Central corneal thickness is significantly related to the IOP but may not affect diurnal IOP fluctuation. The axial length was not associated with IOP profiles in this study. Our results can contribute to a broader understanding of the effects of ocular biomechanical properties on the IOP profile.