> Instead of a single row of data on a spreadsheet, I saw two, one below the other

I have keratoconus, where the cornea loses its shape and creates multiple focal points. I have several focal points in each eye.

It got so bad I couldn't read. So many copies of every letter that text looked like nests of spiders. Not an exaggeration, you could give me a page and a week and I wouldn't be able to decode it.

I also got headaches. Imagine trying to focus when all that does is vary which points in one eye match the other eye. It took a long time for my brain to stop trying.

If I look at a little "power dot" on some device across a pitch-black room, I can clearly see all the focal points, at random distances from a presumed center and each other. And a web of smeared focal lines connecting them.

It sounds cool, but you really don't want a focal web!

Fortunately, surgery involving soaking my cornea with a strengthening substance, and applying lasers to set it, improved my left eye considerably. And then, for unknown reasons, both eyes have improved spontaneously since then.

I feel very lucky to be able to read effortlessly, or at all, again.

For some reason, I sometimes have bad days and see mildly offset multiples. But mostly, the focal points are so closely clustered I don't notice them. Unless I try and read tiny tiny pill-cannister writing.

Now about my damn myopic lenses, ...

For most of my life I had noticeably better than 20/20 vision.

[0] https://en.wikipedia.org/wiki/Keratoconus (I am happy to say, my eyes never looked anything like that picture. They didn't have any visible misshaping. I think my corneas had subtle soft rippling.)