Spectral optical coherence tomography: a new imaging technique in contact lens practice

Purpose: Spectral optical coherence tomography (SOCT) is a new non-invasive, non-contact, high-resolution technique, which provides cross-sectional images of objects that weakly absorb and scatter light. The aim of this article is to demonstrate the application of SOCT to imaging of eyes fitted with contact lenses. Methods: Nine eyes of six different subjects fitted with various contact lenses have been examined with a slit-lamp and a prototype SOCT instrument. Results: Our SOCT system provides high-resolution (4-6 mu m longitudinal, 10 mu m transversal) tomograms composed of 3000-5000 A-scans with acquisition time of 100-250 ms. The quality of the images is adequate for detailed evaluation of contact lens fit. Design, shape and lens edge position were assessed, and complications of contact lens wear could be visualized. Thickness of the lens, corneal epithelium and stroma as well as the space between the lens and the eye surface have been measured. Conclusions: SOCT allows high-resolution, cross-sectional visualization of the eye fitted with a contact lens. The ability to carry out a detailed evaluation of the fitting relationship between the lens and the ocular surface might be useful in research and optometric practice. SOCT can also be helpful in diagnosis, evaluation and documentation of contact lens complications.