Scotoma

Synonyms

Scotomata or scotomas (plural)

Definition

A scotoma is a small blind spot within the visual field. The word scotoma is derived from the Greek word for darkness (σκότος). This “island” of impaired vision can be detected by confrontation testing, perimetry, and scanning laser ophthalmoscope (Cheung and Legge 2005). Causes of scotoma include age-related macular degeneration, retinal infarcts or hemorrhage, demyelinating disorders, migraine, infection, and nutritional deficiency. The position and shape of the scotoma, and whether it is monocular or binocular, help localize the causative abnormality in the visual pathways (Blumenfeld 2002). Various types of scotomata have been described, including central (see Fig. 1), scintillating, fortification, and altitudinal scotoma (Blumenfeld 2002). While scotomata often go undetected due to nystagmus and spontaneous “filling in” by the visual system, they can interfere with daily activities such as reading and driving.

Fig. 1

Central...