# Donut-shaped afterimage

**URL:** <https://boards.straightdope.com/t/donut-shaped-afterimage/733126>\
**Category:** Factual Questions\
**Created:** [October 1, 2015, 1:06pm UTC](https://boards.straightdope.com/t/donut-shaped-afterimage/733126 "2015-10-01T13:06:49Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\
**Post date:** [October 1, 2015, 1:06pm UTC](https://boards.straightdope.com/t/donut-shaped-afterimage/733126/1 "2015-10-01T13:06:49Z")

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When I close my eyes, I often see what appears to be a donut-shaped afterimage, as if I’d been looking at a similar-shaped bright object. But I had not been looking at anything so shaped. Could this in fact be related to my eye’s iris? How else could this be explained?

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**Author:** ![Ignotus](https://avatars.discourse-cdn.com/v4/letter/i/ecc23a/32.png) [@Ignotus](https://boards.straightdope.com/u/Ignotus)\
**Post date:** [October 1, 2015, 1:42pm UTC](https://boards.straightdope.com/t/donut-shaped-afterimage/733126/2 "2015-10-01T13:42:04Z")

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They’re called _phosphenes_, and I see them pretty often, usually in the form of several concentric circles in various colors. I don’t think the shape is directly related to the iris; they are somehow produced by the retina, often after applying gentle pressure to the eyes (as when you have been leaning your forehead against your arm).

> **[Phosphene](https://en.wikipedia.org/wiki/Phosphene)**
>
> A phosphene is the phenomenon of seeing light without light entering the eye. The word phosphene comes from the Greek words phos (light) and phainein (to show). Phosphenes that are induced by movement or sound may be associated with optic neuritis.
> Phosphenes can be induced by mechanical, electrical, or magnetic stimulation of the retina or visual cortex, or by random firing of cells in the visual system. Phosphenes have also been reported by meditators (called nimitta), people who endure long ...

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**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\
**Post date:** [October 1, 2015, 2:00pm UTC](https://boards.straightdope.com/t/donut-shaped-afterimage/733126/3 "2015-10-01T14:00:37Z")

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Thanks, Ignotus. 🙂

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**Author:** ![Ignotus](https://avatars.discourse-cdn.com/v4/letter/i/ecc23a/32.png) [@Ignotus](https://boards.straightdope.com/u/Ignotus)\
**Post date:** [October 1, 2015, 3:25pm UTC](https://boards.straightdope.com/t/donut-shaped-afterimage/733126/4 "2015-10-01T15:25:30Z")

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Glad to help!

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**Author:** ![cjepson](https://avatars.discourse-cdn.com/v4/letter/c/a9adbd/32.png) [@cjepson](https://boards.straightdope.com/u/cjepson)\
**Post date:** [October 1, 2015, 4:02pm UTC](https://boards.straightdope.com/t/donut-shaped-afterimage/733126/5 "2015-10-01T16:02:13Z")

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I get the exact same thing, often associated with sinus headaches (presumably, either because of sinus pressure on the retina or because when I get such headaches I tend to rub my eyes).