To comprehensively assess the precision and agreement of anterior corneal power measurements using 8 different devices.

Volunteers with healthy corneas will be measured by different instruments to detect their anterior corneal power. Only the right eye of each subject was selected. Measurements were repeated in the second session scheduled 1 to 2 weeks later.

Inclusion Criteria:

• healthy cornea,
• best corrected distance visual acuity (BCVA) equal to or better than 20/25,
• willing and able to comply with scheduled visits and other study procedures.

Exclusion Criteria:

• History of refractive surgery or any keratoplasty procedure,
• use of contact lenses,
• history of corneal dystrophies or degenerative diseases,
• history of glaucoma or ocular hypertension,
• significant subjective dry eye symptoms, Schirmer I test results of less than 5.0 mm, tear film break-up time shorter than 5 seconds and corneal fluorescein staining positive.

The present study's definitions of reproducibility, repeatability and agreement were based on those adopted by the British Standards Institute and the International Organization for Standardization.

Corneal curvature measurement provides crucial information for calculating intraocular lens power,screening and managing corneal refractive surgeries and corneal disease.

Volunteers with healthy corneas will be measured by different instruments to detect their anterior corneal power.Only the right eye of each subject was selected.Measurements were repeated in the second session scheduled 1 to 2 weeks later, at almost the same time as the first session, by the same examiner using the same protocol.