A pinguecula is a common type of conjunctival stromal degeneration in the

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

. It appears as an elevated yellow-white plaque in the bulbar conjunctiva near the limbus. Calcification may also be seen occasionally.

Etiology

The exact etiology is unknown, but it may be associated with aging and excessive exposure to UV light.

Signs and symptoms

It is seen as a yellow-white deposit on the

conjunctiva In the anatomy of the eye, the conjunctiva (: conjunctivae) is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with gobl ...

adjacent to the

limbus Limbus (Lat. "edge, boundary") may refer to: * Corneal limbus, the border of the cornea and the sclera (the white of the eye) * Limbus of fossa ovalis, in the heart * Limbus 3 and Limbus 4, two line-ups of a German avant-garde musical group * ...

(the junction between the

cornea The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...

and

sclera The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective outer layer of the eye containing mainly collagen and some crucial elastic fiber. In the development of t ...

). (It is to be distinguished clinically from a pterygium, which is a wedge shaped area of fibrosis that may grow onto the cornea.) A pinguecula usually does not cause any symptoms. It is most common in tropical climates and there is a direct correlation with UV exposure. Histologically, there is degeneration of the collagen fibers of the conjunctival stroma with thinning of the overlying

epithelium Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...

and occasionally calcification. Actinic exposure of the thin conjunctival tissue is thought to cause fibroblasts to produce more

elastin Elastin is a protein encoded by the ''ELN'' gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). It is highly Elasticity (physics), elastic and present in connective ...

fibers, which are more twisted than normal elastin fibers and may lead to the degradation of the

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

fibers. Alternatively, it has been postulated that the sub-epithelial collagen fibers undergo degradation and assume the qualities of elastic tissue while fragmenting and twisting in a different configuration from their normal state. It is thought that the high reflectivity of the solid white scleral tissue underlying the conjunctival tissue may result in additional UV exposure to the back side of the tissue. The side of the nose also reflects sunlight on to the conjunctiva. As a result, pingueculae tend to occur more often on the nasal side of the eye. While most pingueculae are found in people over the age of 40, they are not uncommon in 20- and 30-year-old adults who spend significant time in the sun. The surface of the conjunctival tissue overlying a pinguecula interferes with the normal spreading of the tear film. The tear ferning test reveals abnormalities of the mucous component of the tear film, making it useful as a predictor of a person's tolerance of hydrophilic soft contact lenses. Contact lens intolerance can also result from the elevation of the peripheral edge of the contact lens if it overlies a pinguecula. The plural form of ''pinguecula'' is ''pingueculae''. ''Pinguecula'' is derived from the Latin word "pinguis" for fat or grease.

Associated conditions

A pinguecula is one of the differential diagnoses for a limbal nodule. It may have an increased prevalence in

Gaucher's disease Gaucher's disease or Gaucher disease () (GD) is a genetic disorder in which glucocerebroside (a sphingolipid, also known as glucosylceramide) accumulates in cells and certain organs. The disorder is characterized by bruising, fatigue, anemia, low ...

Diagnosis

Diagnosis of pinguecula is usually done by an

eye care professional An eye care professional is an individual who provides a service related to the eyes or vision. It is any healthcare worker involved in eye care, from one with a small amount of post-secondary training to practitioners with a doctoral level of edu ...

during routine

eye examination An eye examination, commonly known as an eye test, is a series of tests performed to assess Visual acuity, vision and ability to Focus (optics), focus on and discern objects. It also includes other tests and examinations of the human eye, eyes. ...

using

slit lamp In ophthalmology and optometry, a slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. It is used in conjunction with a biomicroscope. The lamp facilitates an ...

. Conjunctival

biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, an interventional radiologist, or an interventional cardiology, interventional cardiologist. The process involves the extraction of sampling (medicine), sample ...

may be advised if

malignancy Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not ...

is suspected.

Treatment

Pingueculae may enlarge slowly over time, but it is a benign condition, usually requiring no treatment. Artificial tears may help to relieve discomfort, if it occurs. If cosmesis is a concern, or if there is discomfort in

contact lens Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic ...

use, surgical excision may be done. Occasionally, a pinguecula may become inflamed, a condition called pingueculitis. The cause of pingueculitis is unknown and there are no known infectious agents associated with it. If an inflamed pinguecula is causing discomfort or cosmetic concerns, it may be treated with short course of topical steroid. Laser photocoagulation may also be used to remove pinguecula.

References

External links

{{Eye pathology Disorders of conjunctiva zh:翼状胬肉