annular scotoma
Học thuậtThân thiện
Definition
Noun: A scotoma (an area of diminished or lost vision within the visual field) that is ring-shaped or circular, typically surrounding the point of fixation (the center of the field of vision). It creates a blind spot that encircles, rather than obscures, the central visual area.
Usage
The term is used specifically in medical and optometric contexts to describe a particular type of visual field defect. * The patient's annular scotoma made it difficult to perceive objects immediately surrounding the central point of gaze. * Diagnosis revealed an annular scotoma, indicating potential retinal pathology.
Advanced Usage
- An annular scotoma is often associated with specific eye conditions, such as advanced glaucoma or certain retinal disorders, where it may progress to involve central vision.
Variants and Related Words
- Scotoma (n): The general term for an area of partial or complete loss of vision in an otherwise normal visual field.
- Central scotoma (n): A scotoma affecting the very center of the visual field.
- Peripheral scotoma (n): A scotoma located in the outer edges of the visual field.
Synonyms
- Ring scotoma
Antonyms
- Full visual field
- Normal vision
Related Phrases
- Visual field defect: A broader term encompassing scotomas and other patterns of vision loss.
- Field of vision: The entire area that can be seen when the eye is fixed on a central point.
Noun
- a circular scotoma surrounding the center of the field of vision