Also referred to as a "Topo". 

It does a topographical map of the cornea, so it will map out all the lumps, bumps, and irregularities present

This measures the degree of astigmatism in the cornea, as well as provides Keratometry values

Similar to the Optos, patients have to have their heads angled and then look into the machine at an orange fixation light

Rings will get overlayed on the cornea and map it out