Dark spots on the eye, often called melanosis eye, are pigmented areas on or within the eye. These discolorations can appear as blue, brown, or gray patches on the white part of the eye (sclera), around the colored part (iris), or on the retina. While such spots can cause concern, many forms of melanosis are harmless. Understanding these pigmented areas helps distinguish between common, benign variations and those that may warrant medical attention.
What is Melanosis Eye?
Melanosis eye involves melanin, the natural pigment determining skin, hair, and eye color. Melanocytes are cells that produce melanin. When these cells produce excess melanin in specific eye areas, darker patches or discoloration appear.
One common and harmless form is racial melanosis, also known as benign conjunctival epithelial melanosis. This non-cancerous lesion of the conjunctiva, the thin membrane covering the white part of the eye, is prevalent in individuals with darker skin tones, with over 90% of cases observed in Black individuals and around 5% in White individuals. It usually appears early in life as flat, brown, patchy areas of pigmentation, often near the limbus, where the cornea meets the sclera. These lesions are stable and do not progress to more serious conditions.
Congenital melanosis, including conditions like oculodermal melanocytosis (Nevus of Ota), is present from birth. This condition involves increased pigmentation of eye structures, such as the episclera, sclera, and uveal tract, and can sometimes affect surrounding facial skin. Congenital melanosis often manifests as slate-gray or bluish discoloration of the sclera or increased iris pigmentation. While benign, these lesions are stable throughout life.
Recognizing Potentially Concerning Melanosis
While many forms of melanosis are benign, certain types warrant closer monitoring due to a potential risk of transformation or association with other conditions. Primary Acquired Melanosis (PAM) of the conjunctiva is an acquired pigmentation that can progress to melanoma. PAM appears as a flat, unilateral, patchy, golden-yellow to brown area on the conjunctiva, often seen in fair-skinned, middle-aged or older individuals.
Choroidal nevi, moles located inside the eye in the choroid layer, also require attention. These internal pigmented lesions are usually benign, but a small percentage can transform into choroidal melanoma. Unlike surface melanosis, choroidal nevi are not visible to the naked eye and are detected during a comprehensive eye examination.
Several visual signs indicate a dark spot on the eye might warrant medical evaluation. These include:
Any increase in the size or thickness of the pigmented area, especially if it grows larger than 5 millimeters.
Changes in the lesion’s shape, color (e.g., becoming darker or developing multiple colors), or elevation (becoming raised or lumpy).
The appearance of new blood vessels surrounding the pigmented patch.
Any new symptoms like vision changes, flashes of light, or floaters.
Diagnosis, Monitoring, and Management
When evaluating melanosis, an eye care professional employs diagnostic tools to determine its nature. A thorough slit-lamp examination is a primary method, allowing the doctor to view the pigmented area under magnification and assess its characteristics, such as size, shape, color, and texture. For lesions deeper within the eye, such as choroidal nevi, a fundoscopy visualizes the back of the eye.
Advanced imaging techniques, such as optical coherence tomography (OCT) or ultrasound, may be used. These imaging modalities provide detailed information about the lesion’s depth and internal structure, aiding in accurate diagnosis.
For types of melanosis that carry a potential risk, such as PAM or certain choroidal nevi, regular monitoring is recommended. The frequency of follow-up appointments can vary depending on the specific type of melanosis and its characteristics, often involving annual check-ups. During these visits, the eye care professional looks for any changes in the lesion’s appearance, including growth, changes in pigmentation, or the development of new features.
Treatment for melanosis is not necessary if the lesion is benign and stable. However, in instances where a lesion shows suspicious changes or a biopsy confirms a precancerous or cancerous transformation, treatment may be considered. This could involve surgical removal, cryotherapy (freezing), or laser therapy. Professional evaluation and consistent follow-up are important to ensure any concerning changes are identified and addressed promptly.