Mêasurement of corneal thickness by low-coherence interferometry

A special interferometric technique, which uses light of low-coherence length and the Doppler principle, is applied to measurement of the thickness of the human cornea in vivo. The special construction of the instrument eliminates any influence from eye motions on the thickness results. With a superluminescent diode as a light source, a precision of ~ 1.5 microm is obtained. This is ~ 3-8 times better than the precision of existing instruments. Since interobserver and interinstrument variability are avoided by the measurement principle, the improvement in total accuracy, compared with that when existing instruments are used, should be even better.