Conjunctiva

synonym

Medical: Sclera conjunctiva
lat .: Conjunctiva

definition

The conjunctiva is a part of the eye. As a mucous membrane, it lies on part of the outside of the eyeball and on the inside of the eyelids. It can be changed in the context of diseases, this can be recognized primarily by its color.

anatomy

The conjunctiva (Conjunctiva) consists of two parts.

  1. The conjunctiva tarsi (the Tarsus is part of the eyelids) covers the inside of the upper and lower eyelids as the outermost layer.
  2. The conjunctiva bulbi (the B.ulbus oculi is the eyeball) covers from the outside the part of the eyeball that is not covered by the cornea, i.e. the upper and lower edge, where the dermis (Sclera) runs.

A multilayered, non-cornifying squamous epithelium with mucus-producing goblet cells forms the basic structure of the conjunctiva. The change between keratinizing squamous epithelium of the skin (epidermis) into the non-keratinizing squamous epithelium of the conjunctiva lies on the conjunctiva tarsi.

At the superior fornix (upper bulge), which is located in the depth of the eye socket, the conjunctiva tarsi overlaps from the eyelid into the conjunctiva bulbi of the eyeball. The same is true of the inferior fornix, the lower bulge. The conjunctival sac is formed in these areas.

The conjunctiva is transparent and very well supplied with blood. It is firmly attached to the eyelids, while it is only loosely attached to the eyeball. The conjunctiva is sensitively innervated by small nerve fibers, which are all branches of the trigeminal nerve (5th cranial nerve):

  • Frontal nerve
  • Lacrimal nerve
  • Infraorbital nerve and
  • Nasociliary nerve

The arterial vascular supply occurs via branches of the Ophthalmic artery.

Special structures of the conjunctiva of the eye:

  • The so-called plica semilunaris is a mucosal duplication that is tender, soft and flexible at the inner corner of the eye.
  • A caruncle is a tissue protrusion between the plica semilunaris and the inner corner of the eyelid; it consists of mucous membrane, skin parts and sebum glands.
  • The mucus secreting goblet cells are present throughout the conjunctival epithelium.
  • Acessory tear glands supply the aqueous component of the tear film and are located on the upper edge of the so-called tarsal plate of the upper eyelid and in the area of ​​the fornices.

What is the conjunctival sac?

The conjunctival sac is also known as the conjunctival sac and is an anatomical structure in every person that is located both between the inside of the upper lid and the eyeball and between the inside of the lower lid and the eyeball. Therefore one can differentiate between an upper and lower conjunctival sac.

The conjunctival sac is formed by the envelope folds of the various parts of the conjunctiva and the adjacent cornea and is also used in anatomy Fornix conjunctivae called. Here, the conjunctiva that covers the back surface of the eyelids turns over and then forms the conjunctiva that covers the eyeball.

In healthy people there is always a certain amount of tear fluid in the conjunctival sac, which keeps the surface moist and supple and protects against infection. Medicines can also be applied here in ophthalmology. If the eye is diseased, pus or foreign bodies can be found here, for example, which disrupt the normal function of the conjunctiva and the eye.

Read more on the subject at: Conjunctival sac

Illustration: Horizontal section through the left eyeball, seen from below
  1. Cornea - Cornea
  2. Dermis - Sclera
  3. Iris - iris
  4. Radiation body - Corpus ciliary
  5. Choroid - Choroid
  6. Retina - retina
  7. Anterior chamber of the eye -
    Camera anterior
  8. Chamber angle -
    Angulus irodocomealis
  9. Posterior chamber of the eye -
    Camera posterior
  10. Eye lens - Lens
  11. Vitreous - Corpus vitreum
  12. Yellow spot - Macula lutea
  13. Blind spot -
    Discus nervi optici
  14. Optic nerve (2nd cranial nerve) -
    Optic nerve
  15. Main line of sight - Axis opticus
  16. Axis of the eyeball - Axis bulbi
  17. Lateral rectus eye muscle -
    Lateral rectus muscle
  18. Inner rectus eye muscle -
    Medial rectus muscle

You can find an overview of all Dr-Gumpert images at: medical illustrations

histology

The conjunctiva consists of a multilayer, highly prismatic columnar epithelium in which goblet cells are embedded. The secretion of the goblet cells is part of the tear film.

Function of the conjunctiva

The conjunctiva acts as a kind of outer protective covering of the eye and contributes to the production of the tear film through the secretion of its goblet cells.
This is for that eye vital.

Clinical fact of the conjunctiva

A closer look reveals a lot about the color of the conjunctiva. Redness may indicate conjunctivitis (Inflammation of the conjunctiva) be. A yellowish colored conjunctiva is often the first indication of jaundice (jaundice). This is caused by increased deposition of blood breakdown products. These are no longer red in color like the blood itself, but have a yellow intrinsic color.
Also an anemia (anemia) can be recognized by the conjunctiva on closer inspection. This is then paler, i.e. whiter than usual.

Conjunctivitis is also of clinical importance (Conjunctivitis). It can arise in the context of local processes (e.g. foreign bodies in the eye) but also in systemic reactions (e.g. bacterial infection). Allergic rhinoconjunctivitis, more popularly known as hay fever, is also very common.

Conjunctival diseases

Acute bacterial conjunctivitis

Conjunctivitis (Conjunctivitis) can in principle be triggered by numerous pathogens, but only a few are able to cause severe acute conjunctivitis in healthy people (streptococci, Corynebacterium diphteriae, Neisserien, Haemophilus).
Staphylococcus aureaus, Streptococcus pneumoniae and Haemophilus aegypticus are the most common causative agents of catarrhal conjunctivitis. Infection can occur in a number of ways: air, gastrointestinal tract, and many more.
Typical of an infection with Haemophilus influenzae and Corynebacterium diptheriae is a pronounced swelling of the eyelids. Membranes, on the other hand, are mainly formed with infections Streptococcus pyogenes and Corynebacterium diphtheriae. The so-called petechiale (punctiform) bleeding in the lids are with infections Streptococcus pneumoniae and H. influenzae.

If the conjunctiva is inflamed, there is usually no swelling of the lymph nodes or skin involvement. Complications are severe keratitis (inflammation of the cornea) (especially with Corynebacterium diphtheriae, Neisseries, H. aegypticus), Sepsis (Corynebacterium diphtheriae, Neisseries, Haemophilus, Pseudomonas) Dacryocystitis and scarring.

The choice of the appropriate therapy depends on the severity: A slight conjunctivitis (conjunctivitis) is usually treated with local antibiotics (gentamycin, erythromycin, chloramphenicol, neomycin, gatifloxacin, levofloxacin, ofloxacin, ciprofloxacin, etc.) without smear and determination of the exact pathogen treated with eye drops or antibiotic ointments.

also read: Floxal eye ointment

In severe conjunctivitis associated with eyelid swelling, massive secretion, membrane formation and possibly also corneal inflammation (keratitis), the pathogen is determined by smear, Gram and Giemsa staining and culture of the pathogen on blood and so-called chocolate agar. At the beginning, if the exact pathogen has not yet been determined, treatment is carried out with highly concentrated antibiotics (gentamycin, ceftazidime 5%) and later the treatment is adapted to the exact resistance of the pathogen present. If necessary, irrigation or cycloplegia (paralysis of the ciliary muscle, which leads to paralysis of the accommodation of the eye and mydriasis; e.g. medicinally) of the eye is performed.

Symptoms of conjunctivitis:

Classic signs that indicate conjunctivitis are:

  • Burn
  • itch
  • light pain
  • white or yellow secretion
  • Redness
  • Photosensitivity
  • swelling
  • Papillae (the ophthalmologist will see using the slit lamp)
  • glued eyelids

Gonococcal conjunctivitis

The causative agent of this conjunctivitis is the aerobic, gram-negative diplococcus (N. gonorrhoeae), with preference for the mucous membrane and genital tract. The culture is ideally carried out with slightly increased CO2 pressure on so-called chocolate agar or Thayer-Martin medium. It is important between N. gonorrhoeae and N. meningitidis to distinguish.

In adults, infection usually occurs through self-contamination. Gonococcal conjunctivitis can lead to severe keratitis (inflammation of the cornea), possibly also with perforation, to sepsis, arthritis and dacroadenitis (inflammation of the lacrimal gland).

In addition to various prophylactic agents, a culture is created to treat the disease itself. Inpatient treatment and isolation of the affected person makes sense. Frequent rinsing of the affected eye with isotonic saline solution facilitates healing. In addition, the antibiotic erythromycin is given for topical application and the antibiotic ceftriaxone, penicillin or spectinomycin is given parenterally (as an infusion) for 7-14 days. The sexual partner must also be treated in the case of a disease with gonococci in order to prevent a possible ping-pong effect. If the diagnosis is uncertain, chlamydia must also be treated.

What is a conjunctival cyst?

A conjunctival cyst is a harmless disease of the eye that is relatively common and usually does not cause any problems. This is a bulging of the conjunctival surface. These often occur after inflammation or injury. As a rule, serous, i.e. clear and not viscous, fluid of varying degrees accumulates under the bulge.

Usually the conjunctival cyst is so small that it does not cause any problems. In some cases, however, it happens that the movement of the eyeball feels strange or difficult and one has a proven foreign body sensation. In this case, an ophthalmological check should definitely take place. If in doubt, this should generally be done.

After the examination by the ophthalmologist, the conjunctival cyst is usually punctured. This means that it is pierced and emptied with the help of a needle. This is usually done under a local anesthetic and should never be done by yourself. This is not a painful process. Complications are extremely rare. If, however, inflammation occurs as a result, the doctor should definitely be consulted again.

However, after removal of the conjunctival cyst, recurrences often occur. This means that the conjunctival cyst reappears relatively often and may cause problems again. In this case, the doctor can be consulted again.

Read more on the subject at: Conjunctival cyst

What is conjunctival irritation?

There are many different causes of conjunctival irritation, all of which can cause similar symptoms. Conjunctival irritation should not be equated with conjunctivitis. However, conjunctivitis can irritate the conjunctiva and cause the same symptoms.

In the context of conjunctival irritation, an inflammatory reaction occurs, which results in increased blood flow. Thus, irritation of the conjunctiva typically leads to reddening of the eye, which is accompanied by increased tear secretion. In contrast to irritation of the cornea, conjunctival irritation is not painful. There is also no decrease in visual acuity. Other symptoms can occur, but they do not occur in all cases. For example, a foreign body sensation or purulent secretion should be mentioned here.

Possible causes of conjunctival irritation are a superficial injury, slight infection, an allergy or other systemic diseases. In this case, if it occurs more frequently or for a long time, a doctor should be consulted for clarification.

Swollen conjunctiva

A swollen conjunctiva is also used in medical terminology Chemosis called. In the case of chemosis, as part of pathological processes, fluid accumulates in and under the conjunctiva, known as edema, which makes it appear swollen and stands out from the layers below. The conjunctival edema can result in either a milky-white opacity or severe reddening of the conjunctiva. In addition, there is pain and possibly a decrease in visual acuity.

In addition to inflammation from bacteria or viruses, the cause of a swollen conjunctiva can also be irritation of the conjunctiva. This can happen through superficial damage such as foreign bodies, trauma or UV radiation as well as allergies. Wearing contact lenses for too long can also be the cause. If there is a problem with the outflow of blood or the lymph in the eye socket, the increased pressure can also lead to the development of conjunctival edema. This drainage disorder occurs, for example, after a trauma or a tumor. However, these reasons are rare.

Therapy by the doctor takes place depending on the cause. If inflammation is the reason, it is treated. In the case of allergies, attempts are made to avoid the trigger. Superficial damage to the conjunctiva can be treated with rest, soft contact lenses or, in severe cases, surgery.

Conjunctival tumor

Conjunctival tumors are a rare condition that affects the conjunctiva of the eye.In contrast to other tumors, however, a conjunctival tumor is usually benign and therefore easy to remove and treat, which means that there is usually no long-term damage or negative effects. Nevertheless, malignant, i.e. malignant, tumors occur now and then.

Even a conjunctival cyst can be counted as a conjunctival tumor. The formation of new blood vessels in the conjunctiva, a so-called hemangioma, is also known as a tumor. This doesn't look nice, but it hardly causes any discomfort and is easy to treat. In children, this tumor can even go away on its own. In adults, a hemangioma is surgically removed.

Other benign conjunctival tumors are melanosis and the conjunctival nevus. However, both show a certain risk of degeneration, so that they must be checked regularly in order to prevent damage at an early stage. A conjunctival nevus corresponds to a birthmark that is located on the eye. Melanosis is caused by too much build-up of dark skin pigment.

Malignant conjunctival tumors are carcinoma and lymphoma. Carcinoma is caused by degenerate epithelial cells, while lymphoma arises from cells of the immune system. These do not always express themselves in the same way (changed surface, pain, foreign body sensation) and are sometimes recognized too late. Therapy consists of surgical removal for carcinoma and radiation therapy for both tumors.

Read more on the subject at: Conjunctival tumors

Conjunctival melanoma

The conjunctival melanoma represents the malignant degeneration of the melanosis or a conjunctival nevus. Also due to the frequent controls of the conjunctival nevus or the melanosis, the conjunctival melanoma is a rare but nevertheless serious disease and requires early and decisive therapy.

The conjunctival melanoma is noticeable by a dark spot in the area of ​​the conjunctiva, which is usually thickened and protruding. The area around the conjunctival melanoma is often darkened and has a high density of blood vessels.

The doctor makes the diagnosis based on a clinical examination and tissue analysis through histology. A CT or MRI is made to rule out spreading to the nearby lymph nodes. A metastasis in the rest of the body should also be excluded if there is justified suspicion.

Treatment consists of surgical removal and subsequent radio or chemotherapy. Since the tumor often recurs, close follow-up care is recommended.

Read more on the subject at: Conjunctival tumor

Conjunctival lymphoma

Conjunctival lymphoma is a rare tumor found in the human eye. In contrast to most other tumors, conjunctival lymphoma is malignant and requires therapy. However, the prognosis is good.

The conjunctival lymphoma is noticeable through a painless swelling in the area of ​​the conjunctiva. This is usually slightly reddish and localized on the conjunctiva of the lower eyelid. It arises from degenerate cells of the immune system and can therefore arise both locally and elsewhere in the body.

Therapy should start as early as possible. Due to the different causes and the different places of origin, the therapy can vary greatly. Radiotherapy, chemotherapy and therapy with so-called biologicals can be considered.

Conjunctival bleeding

Conjunctival hemorrhage is a relatively common disease, but it is usually harmless. It can arise from many possible causes and usually does not cause any problems.

A conjunctival hemorrhage is noticeable by a visible, red spot on the conjunctiva. The bleeding is not painful and does not cause visual disturbances. Only a slight irritation of the conjunctiva sometimes occurs. Often it occurs when the pressure inside the eye or blood vessels increases. This is the case with coughing, sneezing, straining, vomiting, exercising, but also with childbirth and high blood pressure. Rubbing the eyes too hard can also cause bleeding.

With drug anticoagulation, conjunctival bleeding can also occur more frequently. This then largely affects old people. Contact lenses or an injury can also be a cause.

Conjunctival hemorrhage resolves on its own within a few days to two weeks and does not require any therapy. Therapy should only be considered in the case of underlying systemic diseases such as high blood pressure or some metabolic diseases such as diabetes mellitus.

Conjunctival tear

A conjunctival tear is a relatively common condition that usually does not have any serious consequences. An external mechanical load causes the conjunctiva to be injured first. This manifests itself as a feeling of foreign body, slight pain and bleeding. There can also be an increased secretion of tear fluid.

While small tears in the conjunctiva heal on their own, large tears are treated by sewing the edges of the wound together. If the affected area becomes inflamed, a doctor should definitely be consulted.