Purpose:
Polarization sensitive optical coherence tomography (PS-OCT) is known to visualize collagenous and fibrous tissues, e.g. trabecular meshwork, and sclera, which are hard to be discriminated in a conventional OCT image. This paper demonstrates the clinical utility and potential benefits of our self-developed office based PS corneal and anterior eye segment OCT (PS-CASOCT).
Methods:
12 eyes of 6 subjects without marked anterior disorder were involved in this study. The PS-CAS OCT system employed in this study was a custom-built compact, user-friendly, and portable office-based prototype developed by the University of Tsukuba in collaboration with Tomey Corporation. The system is based on swept-source PS-OCT technology and has a measurement speed of 30,000 lines/s and a center wavelength of 1.3 um. The system is packed into a compact space of 85cm x 120cm and includes an operator seat, as shown in figure (a). A touch screen displaying a front view of the patient’s eye and a joystick are integrated in a motorized scanning head enabling user-friendly operation and semi-automated alignment of the eye. The eyes were scanned over the area of 4 mm times 4 mm consisting of 512 times 128 depth scans within 2.6 seconds. A standard intensity image (figure (b)) and a polarization sensitive phase retardation image (figure (c)) were simultaneously obtained.
Results:
The trabecular meshwork was clearly visible in the PS-OCT images of 12 of 12 eyes, while, in standard intensity images, it was not visible in all eyes. In 12 of 12 eyes, the sclera showed strong phase retardation in the PS-OCT images. A volumetric measurement revealed the three-dimensional birefringence structure of the anterior eye as shown in figure (d).
Conclusions:
PS-CAS OCT would be a powerful tool to selectively visualize fibrous and collagenous tissues in the anterior eye.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • anterior segment • trabecular meshwork