What instrument is best used to measure the curves of the cornea?

The best instrument to measure the curves of the cornea is the keratometer. This specialized device is designed specifically for assessing the curvature of the anterior surface of the cornea, which is crucial in various applications, including contact lens fitting and understanding corneal health. It measures the curvature by utilizing reflections of light off the cornea, allowing practitioners to determine the shape and steepness of the cornea accurately.

The other instruments mentioned serve different purposes. For example, an autorefractor is primarily used to determine refractive errors in the eye by measuring how light is altered as it passes through the eye. A slit lamp is an essential tool for examining the various structures of the eye in detail, such as the cornea, but it does not measure corneal curvature specifically. The phoropter is mainly used for subjective refraction tests to determine the best corrective lenses for a patient, rather than measuring corneal curvature.