CHAPTER 7

Anterior Chamber and Trabecular Meshwork

Topography

The anterior chamber is bounded anteriorly by the corneal endothelium, posteriorly by the anterior surface of the iris–ciliary body and pupillary portion of the lens, and peripherally by the trabecular meshwork (Fig 7-1). The depth of the anterior chamber is approximately 3.5 mm. The trabecular meshwork is derived predominantly from the neural crest, while the Schlemm canal is derived from mesoderm.

Histologic features of the anterior chamber angle correlate with gonioscopic landmarks (Fig 7-2). The termination of Descemet membrane is manifested gonioscopically as the Schwalbe line. The scleral spur, a triangular extension of the sclera that appears as a white band gonioscopically, can be identified histologically by tracing the outermost longitudinal ciliary body muscle to its insertion. The trabecular meshwork and the Schlemm canal are nested in the groove formed by the scleral spur and corneoscleral tissue (internal scleral sulcus). See also Figures 2-1B and 2-2 in BCSC Section 10,

Glaucoma.

Figure 7-1 The normal anterior chamber angle, the site of drainage for the major portion of the aqueous humor flow, is defined by the anterior border of the iris, the face of the ciliary body, the internal surface of the trabecular meshwork, and the