[Is corneal thickness measurement reliable and useful?]

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optometry

Background:

• Accurate central corneal thickness (CCT) measurement is crucial for diagnosing and managing various ocular conditions.
• Ultrasound pachymetry is a common method for CCT assessment, but its accuracy and reproducibility require thorough evaluation.

Purpose of the Study:

• To evaluate the accuracy and reproducibility of central corneal thickness measurements using ultrasound pachymetry.
• To assess the clinical usefulness of ultrasound pachymetry in diverse patient groups.

Main Methods:

• Calculated intra-observer, inter-observer, and inter-session variability in control subjects.
• Observed diurnal variation and the impact of surgery on CCT.
• Compared CCT and intraocular pressure across six groups: controls, primary open-angle glaucoma, ocular hypertension, normal tension glaucoma, diabetes mellitus, and corneal graft recipients.
• Studied the influence of dorzolamide on CCT.

Main Results:

• Intra-observer variability was 9 +/- 4 microns; inter-observer and inter-session variabilities were 4 microns and 5% respectively.
• Central corneal thickness was significantly greater in ocular hypertension patients (587 +/- 41 microns) compared to controls (548 +/- 32 microns) and other groups (p < 0.001).
• Dorzolamide showed no significant influence on CCT.

Conclusions:

• Ultrasound pachymetry provides accurate and reproducible central corneal thickness measurements.
• This method is clinically useful for selected patients, especially when intraocular pressure measurements are inconsistent with other clinical findings.