A choroidal nevus is an area in the back of the eye that has a darker color and may also have associated findings around it. This area is similar to a freckle on the skin, in that it is differently colored but not considered malignant or concerning.
A choroidal nevus does not require any additional treatment beyond being monitored during routine eye exams.
Where is a Choroidal Nevus Located?
I’m the back of the eye, there are many layers of different structures that help produce vision and provide nourishment for the eye.
The retina is the “top” layer of the back of the eye and the most forward. It is responsible for creating vision and communication with the brain.
Below the retina is the RPE which aids the retina and provides nutrients and disposes of wastes from the retina.
Behind the RPE is the choroid. The choroid is the blood supply for the back of the eye and is composed of many blood vessels and connective tissue.
A choroidal nevus is located in the back layer of the choroid and is below the retina and the RPE.
The Appearance of a Choroidal Nevus
A choroidal nevus is only visible in an eye exam or with special instruments that allow photography of the back of the eye.
When viewing a nevus, the distinct change in color when compared to the surrounding area is the most characteristic aspect of the appearance.
A nevus is usually darkly pigmented and appears brown or black.
A nevus may also have a build-up of orange-colored material called lipofuscin.
There may also be a halo around the nevus.
Concerns with a Choroidal Nevus
While a choroidal nevus is usually a benign finding that does not impact vision, it has the potential to transform into a much more concerning finding.
If choroidal nevus changes into a cancerous lesion called malignant melanoma, it can both impact vision and result in the loss of an eye or death.
Malignant melanoma is a form of cancer that is fairly aggressive and requires treatment to prevent the spread of cancer.
Very few choroidal nevi ever transform into a malignant melanoma but the risk is present.
Treatment for Choroidal Nevus
The main treatment and management for a choroidal nevus are simply monitoring yearly with a dilated eye exam.
At the eye exam, a photo of the nevus may be taken using a retinal camera to document the size and location of the nevus.
Year over year, the choroidal nevus is monitored to check for growth or other irregularities including abnormal borders or discoloration.
If it is suspected that the choroidal nevus is at risk of transforming into malignant melanoma, then a referral to an ocular oncologist may be needed.
At the referral appointment, a B scan ultrasound may be performed on the eye to check if the nevus is hollow or solid.