The blood-aqueous barrier is formed by tight junctions between which cells of the ciliary body?

The blood-aqueous barrier is an essential structure in the eye that helps maintain the avascular nature of the aqueous humor, shielding it from fluctuations in blood composition and ensuring a stable environment for the avascular structures in the front of the eye. The tight junctions that create this barrier are primarily found between the non-pigmented epithelial cells of the ciliary body.

These non-pigmented epithelial cells form a critical component of the ciliary process, which is responsible for the production of aqueous humor. The tight junctions between these cells serve to limit paracellular permeability, effectively preventing the passage of large molecules and ions from the bloodstream into the aqueous humor. This selective permeability is crucial for maintaining the precise ionic composition and pressure of the intraocular fluid, thereby supporting ocular health and function.

While other cell types within the ciliary body play roles in the overall function of the eye, they do not contribute to the formation of the blood-aqueous barrier in the same way. The pigmented epithelial cells, for example, have different roles related to the metabolism and absorption of light and may assist in the production of aqueous humor; however, they do not form the tight junctions that constitute the barrier.