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.)

I got my first bifocals last year. I got the "no line" variety and, so far, I hate them. The focal distances I need for reading, viewing my phone, and other close work are at the absolute bottom of the lens. Likewise, I find the top of bifocal area of the lens interfering with straight-ahead vision sometimes, too.

I'd like to try a set of bifocals with traditional discrete lenses to see if that improves my experience. I'd be curious to hear others' experiences.

re: light - I can definitely tell I have better acuity in bright settings when my irises are "stopped down" to a small pupil. I'm glad of my experience shooting manual focus / aperture cameras because it gives me a good intuition for what the optical instruments in my head are doing.

Edit: Oh, and the damned floater in my right eye. I've had it for 15+ years, and they're not increasing (so it's unlikely a symptom of retinal detachment). Reading on paper or a screen and, oddly, driving, always seems to bring it to the center of my vision. I flick my eye around randomly for a few seconds and it goes away for awhile. I haven't even broached the subject with my ophthalmologist because it's not too bad-- just annoying.

I lament the lack of good light theme choices though because the majority use dark mode, and dark mode is increasingly becoming the default setting which I don't particularly like, but as long as there's a choice its fine.

I don't do much work on a screen in the dark anymore though to where dark mode would be necessary. My home office is surrounded by big windows with a ton of natural light.

I had to wear contact lenses since junior high because my eyes were so warped that glasses couldn't correct my vision. This was fine but when I hit fifty I started wondering what I'm going to do when I'm really old - I couldn't see myself caring for my scleral lenses at 80 or whatever.

My eyes started to develop cataracts at 50. I was lucky and found a great eye surgeon who implanted custom toric lenses. I can now see well enough that I can legally drive a car without lenses. I can read books at night on my phone without lenses. I start my day in the morning on the computer programming without lenses but in the afternoon I usually put on reading glasses and continue...

Anyway, I'm so much better off after my cataract surgery than I was before. However I have relatives that are worse off after. I think part of it is my warped eye - I can focus different distances because of it. But also I had a great ophthalmologist which sounds like the major difference.

I don’t know who on Hackernews first mentioned these red light glasses but bought them for my mom in the hopes it could alleviate some vision problems she was having. After reading the precautions and fine print she was scared to try them, so I figured, why not see if there’s a difference for me. I don’t know how to describe it other than my eyes feel well rested when I use these consistently. I can see better in the dark and depth perception is just slightly better. I’ll use these puppies forever.

If I remember correctly, it contains some stuff from ordinary grape seeds that helps to orient back the fibers in a vitreous body.

Hence the at least 6 months to understand whether it works or not — new tissue takes time.

For most people it becomes inflexible first, and you might have trouble squeezing the lens and it limits your range of focus. This is when most people need reading glasses.

I had problems with cataracts, when the lens further gets cloudy.

Most people eventually get cataracts due to age, but some conditions can speed up the process and you get them earlier.

When I had the problem, I had trouble with glare while driving, and seeing a bright computer screen was a chore.

I switched to dark mode for reading and computer use and it really helped. It was such a relief.

For driving, the glare was like shining headlights on a dirty windshield. Some situations like bright tuner headlights on a rainy night were confusing and required extra care. It helped to use polarized driving glasses, but only a bit.

When this stuff gets to be too much, people get cataract surgery to replace the lens. This operation is pretty well sorted, it takes a few minutes to replace the lens, and most people really enjoy the results.

for me, I chose single-vision lenses. I got very very good 20/20 vision at a distance and used reading glasses for near vision. There are lots of types of reading glasses available and I have lenses for my computer. I can use very small fonts, and dark mode is completely optional.

Funny, but driving at night is a big change. I can see clearly and headlights have switched the type of glare. I can now focus on bright headlights and now the problem is all that light focuses perfectly on probably one cell on my retina and is almost painfully bright.

(there are two kinds of glare - disability glare the kind I used to have, and now discomfort glare with a reaction to the absolute brightness)

oh, and now that I focus at infinity, getting reading glasses is easy. the formula for it is:

1 / distance-in-meters = +x.xx diopters.

So to read your phone at .5 meters, use 1/.5 = +2.00 diopter reading glasses.

My computer screen works out to +1.25 diopter.

Really close project stuff is +3.0 or more

https://en.wikipedia.org/wiki/Cataract

https://en.wikipedia.org/wiki/Glare_(vision)

https://en.wikipedia.org/wiki/Dioptre

https://www.nccdp.org/the-connection-between-dementia-and-vi...

The eyes connect to the back of the brain and just above the evolutionary older cortext. When those signals start failing, there's some deeper change going on.

I see my whole room unless it is pitch black inside.

Most people who like dark mode use it so they can be in a dimly lit room and not have the display blast their eyes with light but I’ve found that under low ambient light my vision is far blurrier - a well lit room complemented by light mode (ie natural, default) display is the easiest to read.