Scotoma refers to an area of decreased or absent eyesight within your field of vision. This is sometimes called a blind spot. It may appear as a dark or grey area of vision loss (visual field defect) that is surrounded by a ring or an area of blurred vision.
There are two types of scotoma:
- Central scotoma. In this type, the blind spot is in the middle of the field of vision. A central scotoma may be caused by a problem with your main nerve for vision (optic nerve). It may also be caused by a common eye disease of older age (macular degeneration).
- Peripheral scotoma. In this type, the blind spot is at the edge of the field of vision. A peripheral scotoma is often caused by a problem with the cells in the back of your eye (retina) that collect images and send them to your brain through the optic nerve.
Other causes of scotoma include multiple sclerosis, stroke, migraine aura, a blood clot to the vessels of the eye, glaucoma, or anything that may block normal light transmission and perception by the retina. To find the cause, you may need to see a health care provider who specializes in eye conditions (ophthalmologist).
- Tell your health care provider about any changes in your scotoma.
- Do not drive or operate heavy machinery unless your health care provider approves.
- Work with a vision therapist as directed by your health care provider.
- When you are reading or doing other activities that involve small objects or small text, try to use good lighting, large print, and magnifying devices.
- Take medicines only as directed by your health care provider.
- Keep all follow-up visits as directed by your health care provider. This is important.
- Your condition changes.
- Your symptoms get worse.
- You develop other symptoms, including:
- Eye pain.
- Flashing lights in your field of vision.
- Shadowy shapes that move across your field of vision (floaters).
- Eye redness.
- You have a sudden loss of vision.
- You have a sudden severe headache.
- You have sudden weakness or numbness.
- You lose the ability to speak, understand speech, or both.