What is the primary purpose of a keratometer?

The primary purpose of a keratometer is to measure corneal curvature. This instrument is essential in the field of optometry and contact lens fitting because the curvature of the cornea directly affects how light is focused on the retina, which in turn influences overall visual quality. By accurately measuring the radius of curvature of the cornea, practitioners can determine the best type and fit of contact lenses for patients, ensuring optimal vision correction and comfort.

Measuring lens thickness and evaluating tear film stability, while important aspects of eye care, are not functions of a keratometer. Similarly, visual acuity testing is conducted using different instruments and methodologies focused on assessing the sharpness of vision rather than measuring corneal shape. Therefore, the correct selection emphasizes the keratometer's specific role in assessing corneal curvature, which is vital for appropriate contact lens fitting practices.