It is estimated that in the United States, choroidal nevi can be found in 4.6 to 7.9 percent of Caucasian individuals1 and that one in approximately 8,000 of these nevi transform into melanoma2. It is this rare ability that makes these lesions clinically significant.
Choroidal nevi are typically discovered during routine dilated fundus examinations and are usually asymptomatic. However, some may be associated with central and peripheral vision loss secondary to subretinal fluid, cystoid retinal edema or, rarely, neovascularization3. Choroidal melanoma also tend to be asymptomatic, but are more likely to be symptomatic than benign nevi, presenting as decreased vision, flashes or floaters.
In their study, Cheung et al. suggest that there are phenotypical markers and environmental risk factors that predispose a person to developing choroidal melanoma. A later study4, using optomap®, determined that choroidal nevi were also present in subjects who did not conform to a particular phenotype. Gordon-Shaag et al. concluded that it was the expanded view (200°) of ultra-widefield (UWF™) technology that improved their ability to locate nevi. This was further supported by Brett et al., who concluded that the optomap was the most effective device for pinpointing choroidal nevi5.