A<unk>  (Greek: darkness; plural:<unk> s" or<unk> ta") is an area or island of loss or impairment of visual acuity surrounded by a field of normal or relatively well-preserved vision.
Every normal mammalian eye has a<unk>  in its field of vision, usually termed its blind spot.  The presence of this normal<unk>  does not intrude into consciousness because it is very small, but it can be demonstrated to oneself by the simplest of clinical methods (such as the one in the blind spot article).
Scotoma
Apudoma
Bowenoid papulosis
Melasma
Erythrasma
Halo nevus
Otosclerosis
Band keratopathy