Optical phase modulation by natural eye movements: application to time-domain FF-OCT image retrieval

TL;DR

This paper demonstrates that natural eye movements can be harnessed to modulate optical phase for tomographic imaging, enabling simplified, high-resolution in vivo ophthalmic imaging without complex synchronization.

Contribution

It introduces a novel method utilizing natural eye movements for phase modulation in TD-FF-OCT, reducing device complexity and improving in vivo imaging capabilities.

Findings

Successful in vivo human corneal imaging with phase modulation

Optimal camera and piezo modulation parameters identified

Eye movements can replace traditional phase-shifting mechanisms

Abstract

Eye movements are commonly seen as an obstacle to high-resolution ophthalmic imaging. In this context we study the natural axial movements of the in vivo human eye and show that they can be used to modulate the optical phase and retrieve tomographic images via time-domain full-field optical coherence tomography (TD-FF-OCT). This approach opens a path to a simplified ophthalmic TD-FF-OCT device, operating without the usual piezo motor-camera synchronization. The device demonstrates in vivo human corneal images under the different image retrieval schemes (2-phase and 4-phase) and different exposure times (3.5 ms, 10 ms, 20 ms). Data on eye movements, acquired with a 100 kHz spectral-domain OCT with axial eye tracking, are used to study the influence of ocular motion on the probability of capturing high-signal tomographic images without phase washout. The optimal combinations of camera acquisition speed and amplitude of piezo modulation are proposed and discussed.