Many people notice accumulated discharge or a small, fleshy bump in the corner of their eye. This area, known as the medial canthus, houses specialized tissues crucial for eye health and function. Understanding these parts helps clarify their role in maintaining eye comfort and cleanliness.
Identifying the Structures
The inner corner of the eye contains two distinct structures: the lacrimal caruncle and the plica semilunaris. The lacrimal caruncle is a small, pink, globular nodule situated at the inner corner. This fleshy bump is composed of skin, fine hairs, and various glands, including sebaceous (oil) and sweat glands.
Adjacent to the caruncle, closer to the eyeball, is the plica semilunaris, also known as the semilunar fold of the conjunctiva. This is a small, crescent-shaped fold of the conjunctiva, the thin membrane that lines the eyelids and covers the white part of the eye.
Their Purpose
The lacrimal caruncle, with its specialized glands, contributes to the tear film by producing oily and mucous secretions. The fine hairs on the caruncle help to trap small particles and debris, preventing them from entering the eye.
The plica semilunaris is a vestigial remnant of the nictitating membrane, or “third eyelid,” found in many animals like birds and reptiles. Although largely reduced in humans, it plays a minor role in eye movement by helping tear drainage and allowing greater eyeball rotation without conjunctival restriction.
Understanding Eye Discharge
The “sleep” or “eye boogers” often found in the corner of the eye upon waking is normal eye discharge, medically termed rheum. This discharge is a mixture of mucus, oil, dead skin cells, and other debris collected from the tear film. During the day, blinking helps to flush these substances away, but during sleep, when blinking stops, the discharge collects and can dry, forming a crusty or sticky residue.
Normal eye discharge is clear, white, or a pale cream color. It removes waste products and potentially harmful debris from the eye’s surface. While a small amount of discharge is common and harmless, changes in its color, consistency, or amount can indicate an underlying issue.
When to Consult an Eye Care Professional
While some eye discharge is normal, certain symptoms warrant a visit to an eye care professional. If eye discharge becomes excessive, changes color to yellow, green, or gray, or is accompanied by other concerning signs, it could indicate an infection or other eye condition. Symptoms such as persistent eye pain, increased redness, swelling around the eye, sensitivity to light, or blurred vision alongside discharge should prompt a medical evaluation.
These signs could point to conditions like conjunctivitis (pink eye), which can be viral or bacterial, a blocked tear duct, or even a corneal ulcer. If your eyelids are stuck together upon waking due to thick, pus-like discharge, or if you experience a feeling that something is in your eye, seek professional advice. Early diagnosis and treatment can prevent complications.