The microscopic study of corneal structures has always been a challenge for ophthalmologists and researchers. The inherent transparency of the cornea and the strong out-of-focus background are the main obstacles for achieving high-contrast images. In the past few years traditional approaches based on the confocal principle have benefited enormously from the advances in scanning and detection technologies, but at the expense of an increasing complexity.
As an alternative approach to the confocal principle, the use of 1-dimensional or 2-dimensional patterns (structured) for illumination to retrieve the in-focus features in an image may be advantageous for in-vivo imaging. It has been shown that structured illumination (SI) microscopy allows optical sectioning with at least the same resolution as standard confocal microscopy. Image acquisition is potentially faster, as optical sections of the whole field of view are obtained after acquisition of two or three widefield images rather than scanning every point in the field of view. In spite of it, the overall performance of these techniques may be affected by noise features that are particular to SI imaging.
In our lab we study the application of structured-illumination techniques to in-vivo corneal imaging.