Fig. 1. Wide-field choroidal OCT imaging^[22]. (a) Rendering of volumetric wide-field 3D-OCT data; (b) virtual (arbitrary) cross-sectional image showing deep light penetration and ability to visualize choroid and sclera, arrow indicates scleral vessel; (c) the orthographic OCT image of the choroid obtained by integrating signals below retinal pigment epithelium (RPE), with the red line indicating the direction of the cross-section in Fig.1(b); (d)‒(f) OCT projection images at a depth of 30 μm, 80 μm and 200 μm below RPE showing choroidal layers and sclera

Fig. 2. Schematic diagram of TD-OCT system

Fig. 3. Schematic diagram of SD-OCT system

Fig. 4. Schematic diagram of SS-OCT system

Fig. 5. Choroidal nevus. (a) Colour fundus photograph of the left eye showing a flat, pigmented and well-demarcated subfoveal nevus;(b) OCTA B-scan and en face image of choriocapillaris slab show normal vascular flux over the lesion with lack of significant intrinsic vasculature within the nevus

Fig. 6. Angiography of the left circumflex coronary artery. (a) 2D NIRAF diagram; (b) (c) cross section OCT-NIRAF images; (d) the enlarged section shows that the elevated NIRAF co localization with the stent located above the fibrous plaque defined by OCT; (e) cross sectional images of NIRAF negative distal portion of the stent; (f) 3D profile rendering with superimposed NIRAF signals

Fig. 7. Patients with chronic venous ulcers in the lower limbs. (a) Adjacent to normal skin around the ulcer, lymphatic vessels dilate without perfusion; (b) skin sclerosis with a slight increase in punctate blood vessels; (c) large blood vessel points can be seen at the edge of the ulcer, with a high density; (d) in the middle of the ulcer, due to the formation of granulation, a large number of dashed blood vessels, called spots, can be seen

Fig. 8. Rectal malignant tumor.(a) B-scan OCT catheter image of normal rectum; (b) corresponding heme-thiazoline stained tissue section image (H&E image) of normal rectal tissue; (c) B-scan OCT catheter image of human rectal malignant tumor; (d) corresponding H&E image of rectal tumor