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StatPearls . Sweetheart Island (FL): StatPearls Publishing; 2021 Jan-.


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Anatomy, Head and Neck, Eye Conjunctiva

Caleb L. Shumway; Mahsaw Motlagh; Matthew Wade.

Author Information

Introduction

The conjunctiva that the eye offers protection and also lubrication that the eye by the production the mucus and also tears. It prevents microbial entrance into the eye and also plays a duty in immune surveillance. It lines the inside of the eyelids and also provides a spanning to the sclera. It is very vascularized and residence to extensive lymphatic vessels.

The conjunctiva can be split into 3 regions: the palpebral or tarsal conjunctiva, the bulbar or ocular conjunctiva, and also the conjunctival fornices. The palpebral conjunctiva is further divided into the marginal, tarsal, and orbital regions. The bulbar conjunctiva is divided into scleral and also limbal parts. Finally, the conjunctival fornices are separated into the superior, inferior, lateral, and medial regions. The palpebral conjunctiva lines the eyelids. The bulbar conjunctiva is uncovered on the eyeball end the anterior sclera. Tenon"s capsule binding it to the basic sclera. The potential an are between Tenon’s capsule and also the sclera is commonly used for neighborhood anesthesia. The conjunctiva has actually an average thickness of 33 microns. Lastly, the conjunctival fornices kind the junction between the palpebral and bulbar conjunctivas. This protective covering is loosened and flexible, uneven its bulbar counterpart, allowing for movement of the globe and eyelids.

The conjunctiva the the eye consists of one epithelial layer composed of stratified squamous and also stratified columnar epithelium. That is non-keratinized through interspersed goblet cells. Over there are also present in ~ this epithelial class blood vessels, fibrous tissue, lymphatic channels, melanocytes, T- and B-cell lymphocytes, Langerhans cells, and also accessory lacrimal glands. A depth layer, the substantia propria or conjunctival submucosa, is composed of superficial lymphoid and also fibrous tissue. The substantia propria is a organization layer that only exists in the conjunctiva, yet not in other eye tissues. Plenty of lymphocytes, mast cells, plasma cells, and neutrophils are present within this connective tissue layer. Finally, the deepest fibrous layer consists of the nerves and vessels offering innervation and also blood supply to the conjunctiva. Also located within this deep layer are the glands the Krause. <1>,<2>

The conjunctival epithelium has actually a thickness that 3 to 5 cabinet layers thick. The basal cell of the epithelium space cuboidal and become much 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 space especially usual in the inferior and medial conjunctiva and near the medial canthus. Away from the fornix, the number of goblet cell decreases. Additionally, the fornix has actually a greater number of patches of lymphocytes, i m sorry are greatly suppressor T-cells. There room patches of immune cells such as T and also B lymphocytes that form conjunctiva-associated lymphoid tissue (CALT). <2>


Structure and Function

The conjunctiva consists the anterior, non-corneal sections of the globe, and also the fornices and also the palpebrae. The conjunctival epithelium has actually multiple functions. In addition to serving together a physics barrier, the conjunctiva’s goblet cells secrete mucin, i m sorry forms a component of the tear film of the eye. This permits for the ocular surface to keep its healthy moisture layer. The conjunctiva likewise has some immune cell which assist in defense of the ocular surface. <3>


Embryology

The conjunctiva establishes from the ocular surface ar ectoderm. This is the same origin of all other epithelia of the eye, including the cornea and the limbus.<4>


Blood Supply and also Lymphatics

The conjunctiva receive its blood supply from the marginal tarsal arcades, peripheral tarsal arcades, and also the anterior ciliary arteries. The marginal tarsal arcades provide blood it is provided to the palpebral conjunctiva in addition to the fornices. The proximal arcade lies follow me the upper border of the lid, feeding the forniceal conjunctiva and then ending up being the posterior conjunctival arteries which feed the bulbar conjunctiva. The anterior ciliary arteries supply the bulbar conjunctiva and are acquired from the ophthalmic artery. Further, there is connectivity between the blood gives of the conjunctiva, so ultimately, overlap exists between the blood it is provided from both the the bigger vessels come the conjunctiva to some extent. The watershed area of the anterior ciliary arteries, which supply the conjunctiva in ~ the limbus, and the posterior conjunctival arteries, which take trip from the posterior bulbar conjunctiva anteriorly, lies about 3 to 4 mm native the limbus. <5>,<6>


Nerves

The conjunctiva receives sensory innervation from the supraorbital nerve, the supratrochlear nerve, the infratrochlear nerve, the infraorbital nerve, the lacrimal nerve, and also the long ciliary nerves. The superior part is gave by the supraorbital nerve, the supratrochlear nerve, and the infratrochlear nerve. The infraorbital nerve supplies the worse portion. Finally, the lateral part is supplied by the lacrimal nerve, while the lengthy ciliary nerves it is provided the circumcorneal portion.<7>


Muscles

There are no muscles the originate or insert straight on the conjunctiva. Instead, part muscles communicate with components of the eye near the conjunctiva. For example, the great of the eyelid from superficial to deep include the skin, orbicularis oculi muscle, the tarsus, and then the palpebral conjunctiva. The extraocular muscles of the eye, such together the 4 rectus muscles (superior, inferior, medial and lateral recti), insert on the globe at miscellaneous distances, posterior come the limbus. These muscle insertions lie deep to the bulbar conjunctiva.

See more: What Does The Word Cornucopia Mean Ing, Cornucopia Meaning


Physiologic Variants

Conjunctivochalasis refers to redundant conjunctiva, frequently involving the inferotemporal conjunctiva. This can be asymptomatic in part individuals. That is a typical physiologic variant v incidence raising with age. However, the redundant conjunctiva deserve to be connected with symptoms of dried eye syndrome. Some postulate that normal tear meniscus formation is impaired and also that normal tear motion is blocked. Nevertheless, no critical pathologic mechanism has actually been uncovered for this association. <8>,<9>


Surgical Considerations

There are plenty of routine actions that involve the conjunctiva. In conjunctivochalasis, described above, the conjunctiva is grasped with forceps and thermocautery is offered to reason contraction of the redundancy tissue. <10>


Clinical Significance

The surface of the eye is exposed to many external influences. That is at risk to many disorders consisting of dryness, allergy reactions, chemistry irritation, trauma, and also infections. Numerous systemic illnesses an outcome in wake up to the conjunctiva. Sickle-cell anemia, form II diabetes mellitus, hypertension, carotid artery occlusion, and leptospirosis are simply a few diseases that an outcome in transforms to the blood it is provided or the framework of the conjunctiva.

The bulbar conjunctiva can generally be assessed at the slit desk lamp by having the patient look nasally to assess the temporal conjunctiva, and also temporally to evaluate the nasal conjunctiva. The superior and also inferior portions of the bulbar conjunctiva may be assessed by tenderness holding the patient’s eyelid open up while the patient looks increase or down. The palpebral conjunctiva and also fornices may be more daunting to assess however may be assessed making use of a little cotton swab come invert the lid. 

The conjunctiva have the right to be assessed clinically using typical stains at the slit-lamp through a trained ophthalmologist. A little amount that fluorescein dye is applied to the ocular surface, and light v blue filter is offered to detect areas of enhanced stain uptake, indicative that damaged epithelium. Lissamine green and Rose Bengal can also be supplied to stain the ocular surface ar with appropriate absorption filters. If both Lissamine green and Rose Bengal have similar staining characteristics, Lissamine green is much better tolerated through patients and also is thus more frequently supplied in the clinical setting. Various methods exist for grading abnormalities, consisting of the Oxford grading scale and the national Eye academy (NEI) scales. Both of these scales are developed for grading the the conjunctiva and also the cornea. <11>,<12>