NIDEK’s "RS-3000 series" of optical coherence tomography (OCT) devices (including the RS-3000, RS-3000 Advance, and Advance 2) is primarily designed for measuring the fundus and retina; however, by attaching an optional "anterior segment observation adapter" to the main unit, it becomes possible to perform anterior segment OCT imaging and analysis—such as pachymetry—on structures like the cornea and anterior chamber angle.