Keratometer
Keratometer or topography device is used for measuring the reflected image of a ring of light on the exterior dome of the eye formed by the iris, cornea, pupil, and lens. This gives us information about the extent of the curvedness of the cornea in every direction.

Autorefractor
An automated refractor is used for measuring the level of variation in the path of light after it reflects back from the retina.

Phoropter
A phoropter is an instrument that has a set of different lenses. The patient is made to try the different lenses to decide precisely which corrective lens is the most suitable for them.