Ocular birthmarks, also known as eye moles or nevi, are generally present at birth or develop shortly thereafter. While they can vary in their appearance and exact location within or on the eye, they are most often benign.
Common Forms of Ocular Birthmarks
Ocular nevi are among the most common forms of birthmarks found on the eye, akin to freckles on the skin. An iris nevus presents as a small, flat, pigmented spot on the colored part of the eye, the iris. These spots typically appear as brown or yellowish-brown areas.
Another type is the conjunctival nevus, which occurs on the conjunctiva, the clear membrane covering the white part of the eye and the inside of the eyelids. These birthmarks look like a pigmented spot that can range in color from yellow to brown, sometimes containing small cysts. A choroidal nevus, located deeper within the eye on the choroid layer beneath the retina, appears as a dark spot during an eye examination.
Nevus of Ota is a birthmark that affects the skin around the eye, often extending to involve the eye itself. This condition results in increased pigmentation of the sclera, the white outer layer of the eyeball, which may appear bluish or brownish. It can also affect the iris and other parts of the eye.
Port-wine stains, known scientifically as nevus flammeus, are reddish-purple vascular birthmarks that primarily affect the skin. While often found on the face, these stains can extend to the eyelids or the skin surrounding the eye. Ocular melanocytosis refers to a broader condition of increased pigmentation within the eye, which can manifest in various structures, including the uveal tract.
Causes of Ocular Birthmarks
Ocular birthmarks are congenital, meaning they are present at birth or become noticeable shortly after. They arise from an atypical development of specific cells during fetal growth. These marks typically form due to an overgrowth or unusual clustering of pigment-producing cells, known as melanocytes.
In some cases, the formation of these birthmarks involves an overgrowth of blood vessels. The appearance of these ocular birthmarks is not influenced by external factors or environmental exposures during pregnancy or after delivery.
Health Considerations and Monitoring
While most ocular birthmarks are benign and pose no threat to vision or overall health, some have a slight potential for change over time. In rare instances, an ocular nevus, particularly a choroidal nevus, can transform into a malignant melanoma, a serious form of cancer. This risk, though low, necessitates careful observation.
Regular monitoring by an ophthalmologist is recommended for individuals with ocular birthmarks. During these specialized eye examinations, the ophthalmologist checks for any alterations in the birthmark’s characteristics. This includes evaluating changes in its size, shape, color intensity, or elevation from the surrounding tissue.
The ophthalmologist also looks for the presence of fluid under the retina adjacent to the birthmark, which could indicate a change in its nature. Certain symptoms warrant immediate medical attention, such as any noticeable change in vision, the onset of eye pain, increased sensitivity to light, or a sudden, apparent growth or alteration in the birthmark’s appearance.
Treatment Approaches
The majority of ocular birthmarks do not require any active treatment and are primarily managed through regular monitoring. Intervention is usually considered only when the birthmark begins to affect vision or shows signs of potential malignancy. If a birthmark grows to a size that obstructs vision, treatment options may be explored to preserve sight.
Treatment also becomes a consideration if there is a strong suspicion that the birthmark is undergoing malignant transformation. In such cases, intervention aims to prevent the spread of cancerous cells. Occasionally, treatment might be considered for cosmetic reasons, provided the procedure is safe and does not pose a risk to the eye’s health or function.
Treatment modalities can include laser therapy for certain superficial lesions, which uses concentrated light to reduce the pigmentation or size of the mark. For larger or suspicious lesions, surgical removal may be recommended. The decision to treat, and the specific method employed, is always determined on a case-by-case basis by an ophthalmologist, considering the birthmark’s characteristics and the individual’s overall eye health.