Shumway Caleb L., Motlagh Mahsaw, Wade Matthew
Gavin Herbert Eye Institute, UC-Irvine
University of California, Irvine
The conjunctiva of the eye provides protection and lubrication of the eye by the production of mucus and tears. It prevents microbial entrance into the eye and plays a role in immune surveillance. It lines the inside of the eyelids and provides a covering to the sclera. It is highly vascularized and home to extensive lymphatic vessels. The conjunctiva can be divided into three regions: the palpebral or tarsal conjunctiva, the bulbar or ocular conjunctiva, and the conjunctival fornices. The palpebral conjunctiva is further divided into the marginal, tarsal, and orbital regions. The bulbar conjunctiva is divided into scleral and limbal parts. Finally, the conjunctival fornices are divided into the superior, inferior, lateral, and medial regions. The palpebral conjunctiva lines the eyelids. The bulbar conjunctiva is found on the eyeball over the anterior sclera. Tenon's capsule binds it to the underlying sclera. The potential space between Tenon’s capsule and the sclera is frequently used for local anesthesia. The conjunctiva has an average thickness of 33 microns. Lastly, the conjunctival fornices form the junction between the palpebral and bulbar conjunctivas. This protective covering is loose and flexible, unlike its bulbar counterpart, allowing for movement of the globe and eyelids. The conjunctiva of the eye consists of an epithelial layer composed of stratified squamous and stratified columnar epithelium. It is non-keratinized with interspersed goblet cells. There are also present within this epithelial layer blood vessels, fibrous tissue, lymphatic channels, melanocytes, T- and B-cell lymphocytes, Langerhans cells, and accessory lacrimal glands. A deeper layer, the substantia propria or conjunctival submucosa, consists of superficial lymphoid and fibrous tissue. The substantia propria is a tissue layer that only exists in the conjunctiva, but not in other eye tissues. Numerous lymphocytes, mast cells, plasma cells, and neutrophils are present within this connective tissue layer. Finally, the deepest fibrous layer contains the nerves and vessels providing innervation and blood supply to the conjunctiva. Also located within this deep layer are the glands of Krause. The conjunctival epithelium has a thickness of 3 to 5 cell layers thick. The basal cells of the epithelium are cuboidal and become more flattened as they approach the surface. In the area closest to the fornix, the conjunctiva has the greatest number of goblet cells. These unicellular mucous glands are especially common in the inferior and medial conjunctiva and near the medial canthus. Away from the fornix, the number of goblet cells decreases. Additionally, the fornix has a greater number of patches of lymphocytes, which are mostly suppressor T-cells. There are patches of immune cells such as T and B lymphocytes that form conjunctiva-associated lymphoid tissue (CALT).
眼结膜通过分泌黏液和泪液为眼睛提供保护和润滑。它可防止微生物进入眼睛，并在免疫监视中发挥作用。它覆盖眼睑内侧，为巩膜提供一层覆盖物。它血管丰富，有广泛的淋巴管。结膜可分为三个区域：睑结膜或睑板结膜、球结膜或眼结膜以及结膜穹窿。睑结膜进一步分为边缘区、睑板区和眶区。球结膜分为巩膜部和角膜缘部。最后，结膜穹窿分为上、下、外侧和内侧区域。睑结膜衬于眼睑内。球结膜位于眼球前部巩膜表面。眼球筋膜囊将其与下方的巩膜相连。眼球筋膜囊与巩膜之间的潜在间隙常被用于局部麻醉。结膜的平均厚度为33微米。最后，结膜穹窿形成睑结膜和球结膜的连接处。这种保护性覆盖物疏松且灵活，与球结膜不同，它允许眼球和眼睑运动。眼结膜由一层上皮层组成，该上皮层由复层鳞状上皮和复层柱状上皮构成。它是非角化的，有散在的杯状细胞。在这个上皮层中还存在血管、纤维组织、淋巴管、黑素细胞、T淋巴细胞和B淋巴细胞、朗格汉斯细胞以及副泪腺。更深的一层，即固有层或结膜下组织，由浅层淋巴组织和纤维组织组成。固有层是仅存在于结膜而不存在于其他眼组织中的一层组织。在这个结缔组织层中有大量淋巴细胞、肥大细胞、浆细胞和中性粒细胞。最后，最深的纤维层包含为结膜提供神经支配和血液供应的神经和血管。克劳泽腺也位于这个深层。结膜上皮有3至5层细胞厚。上皮的基底细胞呈立方形，随着它们向表面靠近而变得更加扁平。在最靠近穹窿的区域，结膜的杯状细胞数量最多。这些单细胞黏液腺在结膜下和内侧以及内眦附近尤为常见。远离穹窿，杯状细胞数量减少。此外，穹窿有更多的淋巴细胞聚集区，其中大多是抑制性T细胞。有T淋巴细胞和B淋巴细胞等免疫细胞聚集形成结膜相关淋巴组织（CALT）。
