Partial Coherence Interferometry

Synonyms

Optical biometry

Definition

Partial coherence interferometry is an optical biometry of intraocular distances in the eye.

Purpose

Partial coherence interferometry allows precise measurement of central corneal thickness, anterior chamber depth, lens thickness, and axial length of the eye.

Principle

In dual-beam partial coherence interferometry, a Michelson interferometer splits an infrared light beam of high spatial coherence but very short coherence length into two parts, forming a coaxial dual beam. This dual light beam, containing two beam components with a mutual time delay of twice the interferometer arm length difference introduced by the interferometer, illuminates the eye. Both components are reflected at several intraocular interfaces that separate media of different refractive indices. If the delay of these two light beam components produced by the interferometer equals an intraocular distance within the coherence length of the light source, an interference signal...