The influence of central corneal thickness and corneal curvature and axial length on the measurement of intraocular pressure.

PURPOSE: To examine the influence of central corneal thickness (CCT), corneal curvature (CC), and axial length (AL) on intraocular pressure (IOP). METHODS: Eighty-one clinically normal eyes were included in our study. The IOP, CCT, CC, AL were measured using a Goldmann applanation tonometer, optical pachymeter, keratometer and A-scan ultrasound biometer respectively in all subjects. RESULTS: A highly significant positive correlation was identified between IOP and CCT. Linear regression analysis suggests that an increase in CCT of 0.010 mm is associated with a 4.946 mmHg increment in IOP. No significant positive correlation was identified between IOP and CC. P values are 0.724 and 0.414 respectively for vertical and horizontal readings. A paradoxically reversed correlation was present between IOP and axial length. CONCLUSION: Corneal thickness is a very important confounding factor in the measurement of intraocular pressure, which warrants further attention in our clinical practice.