Corneal parameters and difference between goldmann applanation tonometry and dynamic contour tonometry in normal eyes

Area of Science:

• Ophthalmology
• Biomedical Engineering

Background:

• Intraocular pressure (IOP) is a key metric in glaucoma diagnosis.
• Accurate IOP measurement is crucial for patient management.
• Goldmann applanation tonometry (GAT) is the established standard, but newer devices like dynamic contour tonometry (DCT) offer alternative methods.

Purpose of the Study:

• To compare IOP measurements between DCT and GAT in healthy eyes.
• To investigate the relationship between IOP measurements and corneal parameters (central corneal thickness, corneal volume).

Main Methods:

• 118 healthy eyes underwent IOP measurement using both DCT and GAT.
• Central corneal thickness and corneal volume were measured using a Pentacam Scheimpflug camera.
• Measurements were taken in a specific sequence: Pentacam, DCT, then GAT after a 10-minute interval.

Main Results:

• DCT measurements (10.5–25.1 mm Hg) were significantly higher than GAT measurements (11–22 mm Hg).
• A statistically significant correlation was found between IOP measurement differences and central corneal thickness and corneal volume.
• No significant correlation was observed between IOP differences and corneal radius or age.

Conclusions:

• A discrete correlation exists between GAT and DCT, but DCT consistently yields higher IOP values.
• DCT may necessitate a re-evaluation of normal IOP ranges if considered a gold standard.
• The GAT and DCT devices are not interchangeable for IOP measurement.