Understanding the precise location and accompanying symptoms of a white spot on the eye is the first step toward determining its cause. The eye is a complex structure, and a white spot can represent anything from a harmless, age-related change on the surface to a rapidly progressing, sight-threatening infection. A spot on the clear outer layer, the cornea, may signal a different issue than one located on the white part, the sclera, or one that originates from inside the eye. Any noticeable change to the eye’s appearance or your vision requires prompt evaluation by an eye care professional.
Non-Infectious Growths on the Eye Surface
Benign growths that form on the conjunctiva, the thin, clear membrane covering the white part of the eye, are common causes for a white or yellowish spot. These growths, known as pinguecula and pterygium, are strongly associated with chronic exposure to environmental irritants like ultraviolet (UV) radiation, wind, and dust. They typically appear near the limbus, the border where the conjunctiva meets the clear cornea.
A pinguecula presents as a yellowish, slightly raised patch that remains confined to the conjunctiva and does not extend onto the cornea itself. This deposit is composed of protein, fat, or calcium. While often asymptomatic, a pinguecula can become inflamed (pingueculitis), causing redness, irritation, or the persistent feeling of grit in the eye.
A pterygium, sometimes called “surfer’s eye,” is a flesh-like, triangular growth that can progressively grow across the cornea. This invasion can distort the surface, leading to induced astigmatism and potentially blurring vision if it reaches the central visual axis. Treatment usually involves lubricating eye drops, but surgical removal may be recommended if it threatens vision or causes significant discomfort.
Urgent Causes: Corneal Infections and Ulcers
A white spot located directly on the clear cornea is often a sign of infectious keratitis, which is an open sore or corneal ulcer requiring immediate medical intervention. This opaque spot represents an active infection and can rapidly progress to cause permanent vision loss. Corneal ulcers are frequently caused by microorganisms, including bacteria, viruses like Herpes Simplex, fungi, or the parasite Acanthamoeba.
The white spot in infectious keratitis is almost always accompanied by severe symptoms such as intense eye pain, light sensitivity (photophobia), excessive tearing, and a noticeable discharge. Contact lens wearers are at a higher risk for these infections, especially those who misuse their lenses by wearing them overnight or failing to clean them properly.
The specific pathogen influences the infection’s presentation; for example, fungal infections may appear with feathery borders. Viral keratitis can cause recurring ulcerations that lead to cumulative scarring over time. A corneal ulcer is considered an ocular emergency because the infection can penetrate deeper layers of the eye, necessitating aggressive treatment to save vision.
Clouding Within the Eye
A white appearance that seems to originate from behind the clear cornea points to different categories of conditions. A cataract is a clouding of the eye’s natural lens, located directly behind the iris and pupil. This clouding causes the lens to become opaque and interfere with light passing through to the retina.
A cataract can appear as a dense, white or grayish-white opacity visible through the pupil. Unlike infectious ulcers, cataracts develop slowly and are primarily related to aging, though they can also occur due to injury or underlying health issues. The symptoms are generally a gradual blurring of vision, faded color perception, and difficulty seeing at night, rather than acute pain or discharge.
A hypopyon is a collection of white blood cells and inflammatory debris (pus) that settles at the bottom of the anterior chamber. This indicates a serious internal eye infection called endophthalmitis. Unlike the chronic development of a cataract, a hypopyon appears acutely and is usually accompanied by severe pain, redness, and a rapid decline in vision, requiring immediate, aggressive treatment.
When to Seek Immediate Medical Attention
A white spot on the eye coupled with certain symptoms indicates a need for immediate emergency evaluation by an ophthalmologist or a visit to the nearest emergency room. If you experience the sudden onset of severe eye pain, especially when paired with a foreign body sensation or an abrupt loss of vision, seek urgent care. The presence of pus, thick discharge, or significant light sensitivity accompanying the spot also signals a potentially sight-threatening process. For contact lens wearers, any red, painful eye must be considered an emergency; remove your lenses immediately and avoid self-treating the condition. Prompt diagnosis and treatment are necessary because even small corneal infections can cause irreversible scarring that permanently impairs vision.