What are scotomas located immediately nasal or temporal to fixation known as?

Scotomas that are located immediately nasal or temporal to fixation are classified as paracentral scotomas. This designation is significant because they are closely associated with the central vision but do not cover the central fixation point itself. Paracentral scotomas can be indicative of specific retinal or neurological conditions impacting the visual field, as they often reflect disturbances in the processing of visual information near the center of the visual field.

In contrast, central scotomas encompass a region that directly affects central vision, which is not the case with paracentral scotomas. Arcuate scotomas, on the other hand, typically follow the contour of the optic nerve and may extend from the optic nerve head towards the temporal side of the visual field. Nasal step refers specifically to a visual field defect that occurs in the nasal portion of vision, characterized by a distinct step-like boundary, which is different from the broader definition of paracentral scotomas.

Understanding these distinctions allows eye care professionals to better evaluate and interpret visual field tests and diagnose underlying ocular or neurological issues.