Abstract
Purpose: :
To demonstrate the capability of depth range extended full-range complex spectral domain optical coherence tomography (FRC-SD-OCT) to image the anterior segment from the cornea to the posterior surface of the lens.
Methods: :
Using an adapted spectrometer design, a SD-OCT system with an extended depth range of 6.5mm was developed. In addition, a full-range complex technique was implemented to double the intrinsic depth range to a total imaging range of 13mm. This corresponds to a fourfold improvement compared to standard OCT systems. The full-range complex method is based on phase modulation that was introduced by off pivot point illumination of the galvo-scanner. A super luminescent diode centered at 835nm with a bandwidth of 18nm was used as light source with an adjusted power of 1.4mW incident onto the cornea. The sensitivity of the system was measured with 106dB close to zero-delay with an A-scan rate of 10kHz.
Results: :
The extended depth range combined with the FRC-technique enabled an axial imaging range from the anterior surface of the cornea to the posterior surface of the lens. The sensitivity was sufficient, to image the structure inside of the cornea and the lens. Images of the whole anterior segments of healthy subjects are presented in 2D and 3D.
Conclusions: :
The high sensitivity and high speed of a SD-OCT system with an extended depth range in combination with FRC-methods enables an imaging range from the front surface of the cornea to the back surface of the lens. Therefore, extended anterior segment imaging FRC-SD-OCT might improve diagnosis of anterior chamber and lens diseases.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • anterior segment