Clinical evaluation of multiparameter correction equations for Goldmann applanation tonometry.

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Corneal Biomechanics

Background:

• Intraocular pressure (IOP) measurement is crucial for glaucoma diagnosis and management.
• Goldmann applanation tonometry (IOPG) is a standard method, but readings can be influenced by central corneal thickness (CCT), corneal curvature (R), and patient age.
• Ethnic variations may affect these influences, necessitating ethnicity-specific corrections.

Purpose of the Study:

• To compare the efficacy of five multiparameter equations in correcting IOPG measurements.
• To evaluate the impact of CCT, R, and age on IOPG and corrected IOP across different ethnic populations (European, African American, Indian).
• To identify equations that best reduce the association of CCT, R, and age with IOP readings.

Main Methods:

• Data from 945 glaucoma patients/suspects (Europeans, African Americans, Indians) were analyzed.
• Five multiparameter equations were used to calculate corrected IOP.
• Regression analyses assessed the variance (r(2)) and residual association of CCT, R, and age with IOPG and corrected IOP.

Main Results:

• CCT was the primary factor influencing IOPG, with R and age having minor effects (4.7-7.5% combined variance).
• The Elsheikh and Chihara equations demonstrated the lowest residual association (0.2-1.8%) of CCT, R, and age with corrected IOP.
• Other equations (Ehlers, Orssengo and Pye, Shimmoyo) showed higher residual associations (1.8-11.7%).

Conclusions:

• The Elsheikh and Chihara equations are superior in reducing the confounding effects of CCT, R, and age on IOP measurements.
• These findings are significant for improving the accuracy of IOP assessment in diverse patient populations.
• Accurate IOP correction is vital for precise glaucoma diagnosis and treatment monitoring.