An “eye freckle” is the common term for a pigmented spot on or inside the eye, which medical professionals refer to as a nevus (plural: nevi). Similar to moles or freckles on the skin, these spots are accumulations of pigment-producing cells and are overwhelmingly benign. Ocular nevi are common in the adult population and typically do not interfere with vision or cause symptoms. They are usually discovered during a routine eye examination.
The Medical Identity of Eye Freckles
The medical name for a pigmented spot depends on its specific location within the eye’s structure. Nevi are categorized into three main types based on their visibility and position.
Iris nevi are found on the colored part of the eye and are the most visible type. These spots can be small and flat (iris freckles) or larger and slightly raised.
A conjunctival nevus appears on the clear membrane covering the white part of the eye (sclera). These spots are often flat or slightly raised, ranging in color from yellow to brown, and sometimes appear cyst-like.
The third and most common type is the choroidal nevus, situated in the choroid layer beneath the retina at the back of the eye. This location means a choroidal nevus is not visible without specialized equipment during a comprehensive, dilated eye exam.
What Causes These Pigmented Spots
Eye nevi form when specialized pigment-producing cells called melanocytes cluster together in a localized area. Melanocytes create melanin, the pigment that determines the color of our skin, hair, and eyes.
Genetics play a role in the likelihood of developing these spots; for example, choroidal nevi are more common in individuals with lighter skin tones. Exposure to ultraviolet (UV) light is also considered a contributing factor, particularly for iris freckles. This suggests that, much like skin freckles, the environment may influence the expression of these pigmented clusters.
Assessing the Risk of Change
Although most ocular nevi are benign, they carry a slight potential to transform into ocular melanoma, similar to a mole on the skin. This risk is the primary reason for monitoring nevi, especially those located in the choroid. Ophthalmologists use specific clinical characteristics to distinguish a stable nevus from an early, potentially malignant tumor.
For choroidal nevi, assessment relies on a set of risk factors often summarized by the mnemonic “TFSOM-DIM.” These factors help identify suspicious lesions that require more frequent monitoring. Key warning signs include increased Thickness (typically greater than two millimeters) and the presence of Subretinal Fluid detected via imaging.
Other concerning features are Orange pigment on the surface of the spot, documented Enlargement in size over time, and location near the Margin of the optic disc. A lesion displaying three or more of these factors has a significantly higher chance of growth and malignant transformation.
Monitoring and Management
When a nevus is first identified, the initial step is to establish a baseline through detailed documentation. This involves specialized imaging, such as fundus photography, to capture the exact size, shape, and color of the spot. Ancillary tests, including optical coherence tomography (OCT) and B-scan ultrasonography, may be used to measure thickness and check for subretinal fluid, especially for choroidal nevi.
For nevi deemed low-risk, a surveillance schedule is recommended to track stability over time, usually at intervals ranging from six to twelve months. High-risk nevi require more frequent follow-up, sometimes every three to six months, to ensure rapid detection of any change.
Treatment is only considered if there is confirmed evidence of growth or transformation into melanoma. Options may include plaque radiotherapy, which delivers targeted radiation to the tumor, or proton beam irradiation. The goal of this intervention is to destroy the cancerous cells while preserving as much vision as possible.