The relationship between central corneal thickness and Goldmann applanation tonometry

Area of Science:

• Ophthalmology
• Optometry
• Biomedical Engineering

Background:

• Goldmann applanation tonometry (GAT) is a standard method for measuring intraocular pressure (IOP).
• Central corneal thickness (CCT) is known to affect IOP measurements.
• The relationship between GAT and CCT in healthy populations requires further investigation.

Purpose of the Study:

• To investigate the correlation between Goldmann applanation tonometry (GAT) and central corneal thickness (CCT).
• To assess the impact of CCT on IOP measurements in a large cohort of healthy individuals.
• To determine if CCT influences the accuracy of GAT in a healthy population.

Main Methods:

• A prospective study analyzed 500 healthy eyes from 500 subjects.
• Goldmann applanation tonometry (GAT) was performed by a single physician, with readings averaged.
• Ultrasonic pachymetry was used to measure central corneal thickness (CCT) in each eye.

Main Results:

• A statistically significant correlation was found between Goldmann applanation tonometry (GAT) and central corneal thickness (CCT) (r = 0.184, p < 0.001).
• No significant correlation was observed between CCT and age, mean spherical equivalent refraction, or visual acuity.
• These findings indicate a potential systematic error in GAT due to CCT variations.

Conclusions:

• Goldmann applanation tonometry (GAT) readings are influenced by central corneal thickness (CCT) in healthy eyes.
• The study suggests a systematic error in GAT accuracy for intraocular pressure (IOP) measurement due to CCT.
• Measuring corneal thickness should be an initial step for optometrists in diagnosing IOP-related pathologies.