Myopia

She isn't lucky because luck has nothing to do with whether or not you get a lazy eye, its all about using glasses to correct the vision and prevent a lazy eye developing.
Basically its this simple
Big difference and no glasses lazy eye
Big difference and correct glasses no lazy eye
Have your dc wear the glasses and then they wont get a lazy eye

No she isn't.
Wearing glasses prevent a child with a large difference from getting a lazy eye. Luck has nothing to do with it, all that is needed is the use of glasses

Astigmatism the gap is 3 diopters, for the normal prescription the gap is 3.5 diopters so it's a pretty big gap when you add it all together. They patched just to try and make my weaker eye do more of the work (possibly to prevent a lazy eye developing?) I'm going back 35 years though so I'm not sure if they do the same thing now. And yes there was always a big gap, it has actually got a bit smaller over the years.

I'm extremely short sighted too. -9.

May I ask what your prescription is and how old you are now?

I am 36.

Why exactly is the gap worrying you @Miraclealltime ? The glasses are to correct the vision, each lens will be what is needed for that eye du the gap doesn't matter.
I've worn glasses for about 30 years. It's never even occur to me that the gap matters. As long as I can see with my glasses then the opticians have done their job.

As others have said try not to worry, I have a big difference in my eyes and a big difference in astigmatism too. I did wear a patch for a while as a kid but I never developed a lazy eye. I have always had one "good" eye and one "bad" eye (both are terrible really 😂) and it's never effected me other than not being able to see without glasses.

And before that, I couldn't afford it.

I can't have it, I've got glaucoma and cataracts.

@Miraclealltime the gap is unlikely to change much and as long as your dc wears the glasses she wont get a lazy eye or have any other major problems.
You really do need to stop worrying and obsessing about this your dc needs glasses thats all nothing to worry about honestly

I’ve always had a large difference in prescriptive strengths ; -8 and - 4. I’ve used both contacts and glasses, the only problem with glasses is the extremely expensive cost I have to pay for the glasses. To balance the strengths, the highest strength lens has to be thinned by the maximum amount, and the -4 lens thinned by the medium thinness.

The point of the glasses is to make both eyes the same and stop them favouring one eye. If one eye is much better they may rely on that eye, the glasses actually help stop that happening.

Talk to your optician if you are worried.

I had a patch aged 4 or 5 have had glasses as long as I can remember both parents are very short sighted and i inherited it. it would have been school eye tests that picked it up. I have -1.2 between eyes and my weaker eye goes back weaker and stronger by a tiny amount every now and again. at 6 i was -7 I couldn't see without my glasses it wouldnt matter about giving the child a rest if without the glasses you look like a blur they need them on all the time. Its cant be cured shortsightness is the shape of the eye. the glasses slow progression but they are for life or lasix when they are older

I have had reading glasses for a few years (am 61). One eye is short sighted and one is long sighted. They just put different lenses in. It probably kept me out of wearing glasses until late fifties as I had both distances covered!

The gap might always be there, as for most people. The important thing is that the glasses will correct this while being worn and her brain will learn to interpret incoming visual messages correctly.

My DD had normal sight in one eye and gross long site in the other. Glasses were used from the age of 18 months to help her see and make sure the brain learned to interpret things properly. It has not been a problem for her, although she has to wear glasses all the time.

Not if they are wearing the glasses as recommended.

I've not had any problems & opticians have never mentioned the possibility of a difference between eyes causing a problem. Myopia can cause a risk of detached retina but that's linked to the severity of the myopia & not the difference between the 2 eyes

I'm very short sighted though my worst eye is -7 so to be honest I wouldn't get very far without glasses.

I've never given it another thought until recently when I developed long sight due to middle age & had to spend out for varifocals.

I started with a gap of 1.5
The -7 gap was a result of an accident that caused sight loss.

As pp has said, lazy eyes may develop if there is a difference that isn't corrected, so the brain relies on the better eye. The difference is going to be corrected by glasses for your child, so shouldn't develop a lazy eye.

For what it's worth, my truck driver uncle has a lazy eye that wasn't picked up in childhood, as there weren't regular eye tests back then. He can do everything anyone else can, except for 3d movies. He needs to re do his truck driving test every 3 years due to the mono vision, but passes it fine.

The only thing I find annoying about having difference in eye strength is that cheap prescription swimming goggles are not strong enough, so I have to pay for more expensive ones. They go up tp -6, but as I am -7 and -8, they corrected to different strengths. It's hardly life limiting though!