scotomata

A scotoma is an area of partial or complete vision loss in the visual field. It is often described as a blind spot, though it is different from the natural blind spot present in everyone's vision due to the optic nerve head. Scotomata can vary in size, shape, and location, and may be stationary or expanding. The perception of a scotoma can range from complete darkness to seeing distortions or shimmering lights.

There are two main types of scotomata: positive and negative. A positive scotoma is when a person is aware of the blind spot and may perceive it as a shadow, a blank area, or even visual distortions. A negative scotoma, on the other hand, is an area of vision loss that the individual is not consciously aware of; they simply do not see anything in that part of their visual field without a specific description of what is missing.

The causes of scotomata are diverse and can include neurological conditions, eye diseases, and certain medications. Common causes include glaucoma, macular degeneration, optic neuritis, stroke, migraines with aura, and tumors affecting the visual pathways. Diagnosis typically involves a visual field test, also known as perimetry, which maps out the entire visual field and identifies any areas of reduced sensitivity or complete loss. Treatment depends entirely on the underlying cause, and while some scotomata can be reversed or improved, others may be permanent.