SD-OCT with prolonged scan depth for imaging the anterior segment of the eye

An 840-nm wavelength spectral domain optical coherence tomography (SD-OCT) with prolonged scan depth was developed and mounted onto a conventional slit lamp for imaging the anterior segment of the eye. X-Y cross aiming was applied to align the SD-OCT scanning position during imaging. An internal fixation target displayed on a miniature LCD monitor was provided. The SD-OCT instrument had an axial resolution of 6 μm and a prolonged scan depth of 7.2 mm. High-quality SD-OCT images, consisting of 2,048 × 2,048 pixels, were acquired of the entire anterior chamber and entire crystalline lens from a healthy subject. The entire cornea, anterior chamber angle, limbus, and iris were clearly visible. Additionally, the internal structure of crystalline lens, including anterior and posterior surfaces of the crystalline lens, capsule, nucleus, and cortex, were clearly imaged with the instrument. The system was also tested in imaging accommodation of the same eye, demonstrating the feasibility of the novel approach for evaluating presbyopia/accommodation.