Comment by drdaeman | Hacker News Reader

Comment by drdaeman | Hacker News Reader

> if they don’t have the right glasses they can develop so-called “lazy-eye” or amblyopia because they’ve never had a sharp image on their retina

I am not a doctor but this sounds strange to me. (I had amblyopia so I have read a little bit about it.)

One eye's vision needs to be significantly different from another, to the extent brain "decides" it cannot merge images and goes mono-ocular.

This trivially happens with e.g. strabismus, when eyes look at different directions. But with poor eyesight corrected with sub-optimal lenses, it would require that only one eye sees significantly blurry image while another eye sees sharp enough (otherwise person would squint or tilt glasses, adjusting for both eyes - so, no reason for amblyopia to develop).

It is not unusual that a person may have different eyesight with their left and right eye (IIRC that's called anisometropia), but I think it must be quite unusual to have glasses that fail to account for this. Even if glasses are sub-optimal, the difference should be consistent, shouldn't it?

Scarred retina on one of my eyes here, due to blunt trauma as a child. If I close my good eye, everything appears as if through a heavy noise filter. Can read letters if super enlarged fonts though, with a bit of work.

My vision appears mainly monoscopic, with the damaged eye providing perfectly integrated peripheral vision.

It is never "funny" or weird - except if an eye feels tired it would have to almost always be the good one, and I have no problem driving or mountain bike riding. I'm slightly short sighted, wear glasses when out and about (contacts offer very little protection by comparison and are a pain to put on) - always buying premium polycarbonate lenses - but take them off when sitting at a screen (work) or just reading or engaging with anything in close proximity.

I was greatly surprised to find myself being able to experience 3d when watching Avatar at IMAX Melbourne - I'm thinking the largely exaggerated scale helped - the movie was not blurry, but I could strongly sense the depth; I'm very impressed by the brain's ability to make sense of things.

As for the prescription of my bad eye, I just set it to the same as my good - it really doesn't matter, so might as well have them be uniform.

Interesting that you could see 3d. I have only a slightly different RX in my left eye and 3d to me looks like layers of flat objects at different depths. I thought that was just the best 3d had to offer until someone described to me what they were seeing.

I think it is the massive size of the IMAX screen, and relative exaggeration of the left / right isolated images that forces the brain to perceive it.

In real life I struggle to tell the difference if I close my bad eye - which leads me to think I don't see in 3d. Brain perceives depth purely through focus; when looking at this phone as typing, the only change if closing the bad one is peripheral vision (Venn diagram/what good eye can't see) being dropped.

Good chance you've only seen 2d movies converted to 3d then, Because those definitely look like paper cutouts.

I saw Avatar in 3d at Imax and it looked like paper cutouts to me. Although I do at times get flashes of a full 3d experience from time to time. Magic eye posters also look like paper cutouts to me, but maybe that is the same for everyone.

You mention you had amblyopia, I'm curious how you got rid of it?

I've had strabismus (i.e. diplopia / double vision) for as long as I can remember. It's pretty minor and I didn't even wear glasses until my 20s but it's such a PITA having to wear 2 different pairs of glasses.

I understand there's a surgery that corrects strabismus where they adjust the eye muscles, just wondering if you or any other HN folks have tried the surgery. The idea of eye surgery is slightly terrifying but would make coding (especially late at night) a lot more comfortable.

These may be useful:

http://www.convergenceinsufficiency.org

http://www.strabismusworld.com

http://stereosue.com

https://nocturnalfred.github.io/strabismicapp/

https://youtube.com/user/VisualExercises

Thanks, great links! I bought the 'Fixing My Gaze' audiobook and I am researching vision therapy as a potential surgery alternative.

> You mention you had amblyopia, I'm curious how you got rid of it?

I had surgery.

In my particular case (large-angle strabismus) this was the only sensible option - no amount of therapy would've helped in my case.

If you'd consider a surgery, I'd suggest to talk to at least two different independent doctors (the best you can find and afford) and ask for their opinions on what your possible options are. I basically got a consistent firm "no, not for your condition" and that was it. However, I've heard that for small angles there are ways to fix things with therapy.

Of course, it's somewhat scary but, thankfully, everything went well. The surgery itself proved to be no big deal - sedatives did magic. I was quite nervous, but a few pills I was given had really fixed that. However, there is always a chance of mistake or something not going well, so, of course, one must be wary.

Actually, I had two surgeries. First one was a little bit off and while it corrected most of the problem, a very small angle was still left. I've went through some therapy but, unfortunately, despite my doctor's expectations the muscle had failed to stretch sufficiently.

However, that therapy had semi-fixed the amblyopia - after some exercises with synoptophore I was able to mentally force myself to see with both eyes (with double vision, of course, since alignment was still off). So, after the second surgely, right after the anesthesia paralysis wore off I got my binocular vision back. And I'd say, in my opinion that was really worth it.

Thank you for the detailed reply!

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