Abstract
Purpose: :
To measure heart-rate related distance changes between the cornea and pre-selected reflecting interfaces at the posterior pole of the eye at different angular positions.
Methods: :
Previously presented systems for the measurement of fundus pulsations use light of long coherence length for illumination of the subject’s eye, and, thus, only allow for the observation of distance variations between the cornea and the strongest reflecting retinal layer. Our system, in which light of low temporal coherence is used for illumination, contains a length measurement system based on dual beam partial coherence interferometry and a linear CCD camera for observation of the interference pattern. One mirror of the Michelson interferometer is mounted on a stepper motor, and, thus, allows for measuring the axial positions of the reflecting ocular layers. By moving the same mirror into a certain position the fundus pulsations in the corresponding layer can be observed.
Results: :
In vivo
Conclusions: :
A new method called low coherence tissue interferometry, which allows for the measurement of fundus pulsations at pre-selected layers of the ocular fundus, is presented. This method can be used for the study of axial eye length growth processes and pulsatile ocular blood flow by observing the corneo-scleral distance in experimental animals. In human subjects it could allow for the investigation of macular edema, where a non-parallel movement of the ocular layers is expected.
Keywords: blood supply • image processing