A nevus is generally detected during a routine dilated eye exam and is diagnosed by the ophthalmologist (Eye M.D.) based upon clinical observation. A choroidal nevus usually appears gray in color, but it can also be brown, yellow or a combination of colors.
Once detected, the nevus is photographed. This allows your Eye M.D. to compare the appearance of the nevus the next time you visit to see if there have been any changes. Because a melanoma can sometimes resemble a nevus, your ophthalmologist may ask you to return within six months to have the nevus re-evaluated. A nevus is relatively stable and unlikely to show change within such a short period of time, thus ruling out the possibility that it is a melanoma.
Most nevi are benign and unlikely to cause any problems. In diagnosing a nevus, your Eye M.D. will want to determine if the nevus shows any characteristics that may suggest it could be at risk of developing into a melanoma. Nevi that are orange, thicker than usual or are leaking fluid are considered suspicious.
If a nevus is suspicious, you may need additional tests to ensure that the nevus is not cancerous. These tests include optical coherence tomography (OCT), ultrasound and fluorescein angiography — all imaging techniques that allow your Eye M.D. to better understand the nature of the nevus.