The term scotoma denotes a gap in part of the field of vision. It can manifest as a black spot, in which case it is called a positive scotoma, whereas if it manifests as a blind spot, an area where the patient sees nothing, it is called a negative scotoma. This condition can indicate an ophthalmological condition of the retina, such as is the case with detached retina, or a neurological disorder with a damaged optic nerve
. If a patient complains of a scotoma, the ophthalmologist
performs a visual field
test, such as the Amsler grid, in order to locate it and find the cause.