A scotoma is an area of partial or complete loss of vision within the visual field, surrounded by more normal seeing regions. It can appear as a dark patch, a blurred spot, or a region where objects seem to disappear.
Types and Causes
Scotomas may arise from retinal disease, optic nerve damage, or lesions in the visual pathways of the brain. Central scotomas affect detailed vision and reading, while peripheral scotomas may go unnoticed until visual field testing is performed.
- Macular disorders often cause central scotomas
- Glaucoma typically produces arcuate or peripheral field defects
- Neurological causes can create characteristic patterns that respect the midline
- Temporary scotomas can occur during migraine aura and then resolve
Detection and Impact
Formal visual field testing helps map the size, shape, and location of a scotoma, providing clues about the underlying cause. The functional impact depends on where the defect lies, with central scotomas affecting reading and face recognition and peripheral scotomas influencing mobility and driving.
- People may adapt by using an eccentric fixation point next to a central defect
- Low vision aids and magnification can support detailed tasks
- Regular follow-up monitors whether the scotoma is stable or progressing
- Management focuses on treating the underlying disease where possible
