The acinar and ductal organisation of the tarsal accessory lacrimal gland of Wolfring in rabbit eyelid.

The purpose of this study was to objectively assess the tarsal accessory lacrimal gland of Wolfring and its excretory duct by transmission electron microscopy (TEM). The upper eyelid of 6 female grey rabbits (2 kg) was fixed in the fully extended configuration with buffered glutaraldehyde. At the tarsal/orbital portion of the palpebral conjunctiva, a series of prominent acinar glands were located by both light microscopy and TEM. Cells within the acini were characterised by apical tight junctions and desmosomal connections as well as abundant intra-cytoplasmic osmophillic (secretory) granules. The apical surfaces were profusely decorated with microvilli-like extensions. In the vicinity of the acini, and traversing over several millimetres of adjacent sub-epithelial parenchyma and epithelium, was an extensive system of duct-like spaces lined with secretory cells decorated with microvilli. These ducts run a tortuous course within the palpebral conjunctival epithelium leading to crypt-like termination's along the eyelid inner surface. The tarsal accessory lacrimal gland of Wolfring thus has an acinar structure similar to the main lacrimal glands, and its ducts are lined by secretory cells along the entire tortuous course towards the palpebral conjunctival surface, where the ducts emerge at multiple points at the tarsal/orbital portion of the surface.