Abstract
Purpose: :
To demonstrate applicability of high–speed, high–resolution Spectral Optical Coherence Tomography (SOCT) cross–sectional imaging of the eye surface. To identify ocular surface pathologies, where this novel imaging technique yields new information of clinical value. To introduce new two– and three–dimensional scanning protocols for architectural morphology imaging of these pathologies.
Methods: :
New high–speed Spectral OCT instrument constructed at Nicolaus Copernicus University (Torun, Poland) has been optimized for high resolution imaging of the anterior segment of the human eye in vivo. This instrument is based on Fourier domain detection, which enables increasing the speed of imaging by 60 times comparing to standard OCT techniques and high sensitivity (96 dB). In turn, high speed of the imaging device enables reconstructing three–dimensional information about ocular structures. Both central wavelength of the light source of 830nm and the spectral bandwidth of 70nm allow imaging of the ocular surface with high axial resolution of 4.5um. The prototype SOCT instrument works under clinical conditions in Ophthalmology Department (Collegium Medicum NCU, Bydgoszcz, Poland). So far, anterior segments of 60 patients have been examined with the aid of the instrument, including 29 eyes with various pathologies of the ocular surface (blebs after glaucoma filtration surgery, corneal surface diseases and defects, conjunctival folds and tear menisci in dry eye syndrome). All SOCT measurements were followed by a slit lamp examination.
Results: :
Our SOCT instrument provides high–resolution (4.5µm axial x 10µm transverse) tomograms composed of 1024 A–scans with acquisition time below 0.1 second. The quality of the acquired images is adequate for precise cross–sectional evaluation of various pathologies of the ocular surface. Three–dimensional scanning protocols enable better visualization of architectural morphology. Precise objective measurements of the pathological changes as well as corneal pachymetry can also be performed.
Conclusions: :
SOCT allows high–resolution, two– and three–dimensional, cross–sectional imaging of various ocular surface pathologies that can be useful in clinical evaluation and research. New instrument provides valuable information supplementary to this obtained by slit lamp examination.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)