Dual channel dual focus optical coherence tomography for imaging accommodation of the eye

Abstract

A dual channel dual focus spectral-domain optical coherence tomography was developed for imaging the accommodation of the eye in real time. The system can provide simultaneous cross-sectional imaging of all the surfaces of the anterior segment of the eye including the cornea, anterior chamber, anterior and posterior surfaces of the crystalline lens. Thus, the modification of the curvatures of the anterior and posterior surfaces of the crystalline lens and the dimensions of the anterior segment of the eye with accommodation can be calculated. The system was successfully tested in imaging accommodation. The preliminary results demonstrated the feasibility of this novel approach.

Effect of Punctal Occlusion on Tear Menisci in Symptomatic Contact Lens Wearers

“…The power of the incident light delivered into the eye was set to a safe level of 750 mW. 25,26 The calibrated axial resolution of the system was ;3 mm in tears or tissues of the eye. The scan width was up to 15 mm, with a depth range of 3 mm in air.…”

Versatile optical coherence tomography for imaging the human eye

“…The SNR decrease is an inevitable defect in SD-OCT. Another disadvantage of long-scan-depth SD-OCT is the limited focus of the objective lens. Therefore, to achieve an extended scan depth and sufficient resolution for the whole ocular anterior segment, some special techniques, including complex conjugate image removal [2,10,11], dual-channel dual-focus [12,13], and optical switching, have been proposed [14,16]. To overcome the SNR drop-off, we used the two-mirror reference arm approach [15], and others used three mirrors in the reference arm to acquire multiple images [16].…”

“…Some techniques have been proposed to extend the scan depth of SD-OCT. A phase shift doubled the image depth with a single focus and successfully imaged the whole anterior segment [2,10,11]. A dual-channel, dual-focus OCT system was used to simultaneously image the anterior segment and retina [12,13]. With a switchable reference arm using a galvanometer, the zero delay line was alternatively placed on the anterior cornea or posterior lens with the acquisition of two images, and the whole anterior segment was visualized by registering and overlapping the two images by our group [14,15].…”

Ultra-high resolution and long scan depth optical coherence tomography with full-phase detection for imaging the ocular surface

“…Thus, sufficient resolution over the full image range is impossible. An alternative choice is using dual-channel dual-focus OCT proposed by Zhou et al,26 but the SNR of the system was decreased due to the attenuation of 50% of the reflected light. Another choice is using a switchable reference arm (overlapping two images when the zero-delay line was alternatively placed on the top or the bottom of the images) 27.…”