Brown spots in the eye often resemble freckles or moles on the skin. These pigmented areas can appear in various parts of the eye, from the iris to the sclera, and even beneath the retina. While their presence might seem alarming, many brown spots are harmless and do not affect vision.
Understanding Benign Brown Spots
Many brown spots in the eye are benign. These spots, often called nevi, are formed by clusters of melanocytes, which produce melanin, the pigment that gives color to our hair, skin, and eyes. Some nevi are present at birth, while others develop later in life.
One common type is an iris freckle, a tiny, dark brown fleck on the surface of the iris, the colored part of the eye. These superficial spots are harmless and do not progress into melanoma. Iris nevi are similar to iris freckles but are larger and extend deeper into the iris tissue. They may slowly increase in size, but most iris nevi are benign and monitored for changes.
Another type is a choroidal nevus, a flat, pigmented area located in the eye’s back, under the retina in the choroid. These nevi are gray, yellow, or brown and are asymptomatic, meaning they don’t cause noticeable symptoms. Choroidal nevi are often discovered during routine dilated eye exams because they are not visible by looking in a mirror. They are common, occurring in about 5-10% of adults.
Identifying Potentially Concerning Brown Spots
While many brown spots are benign, certain characteristics indicate a need for professional evaluation. Ocular melanoma, a rare form of eye cancer, can manifest as a new or changing brown spot. Symptoms suggesting ocular melanoma include a growing dark spot on the iris, changes in pupil shape or size, blurred vision, or flashes of light or “floaters” in the field of vision.
Pigment dispersion syndrome (PDS) is another condition where pigment cells from the back of the iris shed and accumulate in other parts of the eye. These pigment bits can clog the eye’s drainage system, potentially leading to increased eye pressure, a precursor to pigmentary glaucoma. Many individuals with PDS have no symptoms, but might experience blurred vision or see halos, especially after exercise.
Occasionally, a brown spot could also be a foreign object lodged in the eye. Small particles like dirt, sand, or metal can become embedded, causing symptoms such as sharp pain, irritation, redness, watery eyes, or a scratchy sensation when blinking. If a metal object is involved, it can react with tears and form rust, appearing as a dark spot on the cornea. Prompt removal is necessary to prevent infection and scarring.
When to Seek Professional Advice
Any new brown spot or a change in an existing one warrants a consultation with an eye care professional. This includes changes in size, shape, color, or elevation. Even if a spot is likely benign, regular monitoring helps track changes over time.
Associated symptoms accompanying a brown spot are also a reason to seek immediate advice. These symptoms include blurred vision, flashes of light, new or increased floaters, eye pain, redness, or any discomfort. These signs indicate underlying issues that require timely diagnosis and treatment.
Routine eye examinations are important for detecting brown spots, especially those not visible in a mirror, like choroidal nevi. Regular check-ups allow an eye care professional to examine the eye’s internal structures and accurately diagnose any pigmented lesions, providing peace of mind or initiating appropriate management if needed.