The caruncle is a small, often unnoticed, part of the eye located at its inner corner. This small, fleshy nodule plays a subtle yet important role in the overall health and function of the eye. Understanding its structure and purpose can provide insight into why certain common eye conditions may arise in this specific area.
Anatomy and Function of the Caruncle
The caruncle, also known as the caruncula lacrimalis, is a small, reddish, globular nodule situated in the medial canthus, the inner corner of the eye. It is composed of modified skin, containing sebaceous (oil) glands, sweat glands, and fine hair follicles.
Its sebaceous glands contribute to the oily layer of the tear film, preventing tear evaporation and maintaining eye lubrication. Fine hairs on its surface trap small foreign particles and debris, preventing them from entering the eye. Located within the lacrimal lake, where tears collect, it guides them towards the tear drainage system. This collective function keeps the eye’s surface clean and moist, supporting ocular health.
Common Caruncle Conditions
Its unique composition makes it susceptible to common, typically non-serious, conditions. One frequent issue is inflammation, causing redness, swelling, and tenderness. This often results from irritation due to environmental factors like dust, allergens, or excessive eye rubbing. Known as carunculitis, this inflammation can also occur as part of an allergic reaction, leading to itchiness and discomfort.
Blocked sebaceous or sweat glands can lead to small, pimple-like bumps or cysts. Similar to clogged pores, these may appear as whiteheads or pustules. While benign, they can cause localized discomfort or a foreign body sensation. Caruncular dermoid cysts, rare benign tumors present from birth, may appear as flesh-colored or yellowish lumps, usually asymptomatic unless causing cosmetic concern or discomfort.
Another common growth near the caruncle is a pinguecula, a yellowish, slightly raised bump on the white part of the eye, often at the inner corner. While pingueculae do not typically grow onto the cornea, they can become inflamed (pingueculitis), causing redness, swelling, and a gritty sensation. These growths are often linked to prolonged exposure to UV light, wind, and dust. Though generally harmless, they can be mistaken for more serious conditions.
When to Seek Medical Attention
While many caruncle issues are minor and resolve on their own, certain signs warrant prompt medical evaluation. Persistent pain, significant vision changes, or an increase in lesion size should be assessed by an eye care professional. Severe discharge, especially with fever or chills, could indicate an infection requiring immediate treatment.
Rapid growth of any mass, bleeding, or an irregular/ulcerated surface are also important warning signs. Although malignant lesions are rare, these features could indicate a more serious underlying condition. An eye doctor can accurately diagnose the issue through examination and, if necessary, recommend further tests or treatment to ensure eye health.