Spectral Optical Coherence Tomography Measurements Research Articles

Comparison between spectral optical coherence tomography and the FFT-based impulse-response reconstruction method in the transmission configuration

We present a comparison between the well-known spectral optical coherence tomography (SOCT) technology and the fast-Fourier-transform-based (FFT-based) impulse-response reconstruction method (FIRRM), which we developed—both in the transmission configuration. It is shown that, since the transmission configuration requires relatively long interferometers, the SOCT measurements are less stable than those of the FIRRM, as seen in the impulse-response reconstruction of the two methods. The FIRRM results show much better agreement with theoretical predictions.

Spectral Optical Coherence Tomography in Video-Rate and 3D Imaging of Contact Lens Wear

To present the applicability of spectral optical coherence tomography (SOCT) for video-rate and three-dimensional imaging of a contact lens on the eye surface. The SOCT prototype instrument constructed at Nicolaus Copernicus University (Torun, Poland) is based on Fourier domain detection, which enables high sensitivity (96 dB) and increases the speed of imaging 60 times compared with conventional optical coherence tomography techniques. Consequently, video-rate imaging and three-dimensional reconstructions can be achieved, preserving the high quality of the image. The instrument operates under clinical conditions in the Ophthalmology Department (Collegium Medicum Nicolaus Copernicus University, Bydgoszcz, Poland). A total of three eyes fitted with different contact lenses were examined with the aid of the instrument. Before SOCT measurements, slit lamp examinations were performed. Data, which are representative for each imaging mode, are presented. The instrument provided high-resolution (4 microm axial x 10 microm transverse) tomograms with an acquisition time of 40 micros per A-scan. Video-rate imaging allowed the simultaneous quantitative evaluation of the movement of the contact lens and assessment of the fitting relationship between the lens and the ocular surface. Three-dimensional scanning protocols further improved lens visualization and fit evaluation. SOCT allows video-rate and three-dimensional cross-sectional imaging of the eye fitted with a contact lens. The analysis of both imaging modes suggests the future applicability of this technology to the contact lens field.