What is the primary contributor of glucose to the cornea?

The cornea primarily derives its glucose from the aqueous humor. This is due to the unique structure of the cornea, which is avascular (lacking blood vessels) and relies on diffusion for nutrients. The aqueous humor, which is produced by the ciliary body, contains glucose as one of its components and is constantly in contact with the corneal endothelium.

The corneal cells, particularly the epithelial cells, absorb glucose from the aqueous humor through specific transport mechanisms. This glucose is crucial for metabolic processes, especially for the generation of ATP through glycolysis, which is essential for maintaining corneal transparency and cellular health.

While the tear film and palpebral conjunctiva may also play roles in maintaining corneal hydration and sustaining some metabolic needs, they are not the primary source of glucose. Limbal blood vessels, although they supply nutrients to the peripheral regions of the cornea, do not directly contribute glucose to the central corneal area where the metabolism is most active. Therefore, the aqueous humor stands out as the main contributor of glucose necessary for corneal function.