Selective uptake of iron oxide by rabbit conjunctival lymphoid follicles.

Purpose: To determine whether conjunctival lymphoid follicles are preferential sites for uptake of foreign material in the preocular tear film.
Methods: Iron oxide suspension was applied to the eyes of New Zealand white rabbits for selected times, and the conjunctiva was examined histochemically for the presence of iron.
Results: Iron was observed by histochemical staining within conjunctival follicle-associated epithelium at 1 hour and deep within the follicles at 4 hours after exposure. Iron was not seen within nonfollicular conjunctival epithelium or underlying substantia propria at any time after iron oxide application.
Conclusions: Iron oxide in the preocular tear film is taken up preferentially by conjunctival lymphoid tissue, supporting the hypothesis that mammalian conjunctival lymphoid follicles may participate in the acquired immune response to pathogens in the preocular tear film.