With what instrument is the base curve of a rigid lens usually verified?

The base curve of a rigid lens is typically verified using a radiuscope, which is specifically designed for measuring the curvature of lenses. This instrument allows practitioners to accurately assess the radii of curvature on the front and back surfaces of the lens. When using a radiuscope, the measurement is obtained by observing the reflection of a test bubble or a light source on the lens surface and comparing it to calibrated data, thus determining the actual base curve. This is crucial for ensuring proper fitting and optical alignment, as the base curve directly impacts the lens's performance and comfort for the wearer.

Other instruments mentioned, while useful in the field of optics, do not primarily focus on verifying the base curve of rigid lenses. A topogometer is more often used to assess the corneal topography, a keratoscope is utilized for evaluating the anterior surface of the cornea, and a profile analyzer generally assesses the overall shape of a lens rather than focusing solely on its curvature.