Figure 2-1 displays an OCT image of a normal anterior chamber obtained from a healthy human eye [6|. The image is composed of 200 A-scans, and plots the logarithm of optical reflectivity mapped to a false color scale. Clearly identifiable structures include the cornea, sclera, iris, and Jens anterior capsule. The strongest reflected signals arise from the epithelial surface of the cornea, and the highly scattering sclera and iris. Smaller amounts of backscatter are visible from within the nominally transparent cornea and lens. The backscatter intensity gradually decreases from central to peripheral cornea. This signal fading may be attributed to highly angle-dependent backscat-tering from the stromal collagen lamellae, which run parallel to the corneal surface. The limbus appears as the angled interface between the cornea and the sclera. The normal watch glass insertion of the cornea into the sclera is clearlv visible.
Cornea and Angle
By narrowing the field-of-view, OCT can be used to obtain high resolution images of corneal microstructure, A magnified OCT image of the cornea appears in Figure 2-2, which differentiates the corneal epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium based on the differences in their optica! properties. A close-up view of the angle region (Figure 2-3) shows the iris contour and epithelium, the corneoscleral limbus, and the anterior chamber angle. Structures in the angle region such as the trabecular
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