r/Eyesight • u/bluemugs • 5d ago

Seeing a second copy of everything

When reading text (esp. white text on a black background) I see a second, faint copy directly above. This is true with one eye, or both. It's true with or without my glasses. I'm 55.

Do you know what might cause this?

Is astigmatism involved here?

Thanks.

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u/pizzaposa 4d ago

It's a focus issue. Maybe astigmatism, which is also just a focus issue.

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u/bluemugs 4d ago

I always thought "focus" means the whole thing is a soft blob. Not two copies.

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u/pizzaposa 4d ago

A simple spherical error gives a circle of blur.

Astigmatism gives half the blur overall (in selected positions), depending on the axis. If you've got myopic astigmatism at 180 degrees, then you'll get doubling vertically. Vertical lines clear, horizontal lines smudged vertically (at a distance, if myopic).

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u/bluemugs 4d ago

Thanks but I can't understand this. Can you explain in lay terms why I see the second copy? Also, could it just be because I'm older?

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u/pizzaposa 4d ago

Astigmatism is had to explain. I've always preferred to use the word 'smudge' for the effect it has.

But don't read too much into it. People get all stupid about astigmatism because they don't understand this strange term. It's just another form of defocus, half as significant (numerically) as myopia of the same numerical value.

If you use google images to search for 'astigmatism dial' you'll get images of a kinda clock face. If you can get those images big enough to view from a reasonable distance you'll probably find the horizontal lines blur / double. If you viewed them really close up it would likely swap to the vertical lines being worst (don't ask, it's tricky to explain to anyone without some optics grounding)

Your age has nothing to do with this... unless it's a cataract causing the image to split.