Why can you get farsighted glasses (+ prescriptions) off a rack at the dollar store but near sighted glass (- prescriptions) need an optometrist appointment

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Why can you get farsighted glasses (+ prescriptions) off a rack at the dollar store but near sighted glass (- prescriptions) need an optometrist appointment

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Anonymous 0 Comments

Part of me wants to say you need them more so they are ‘worth’ more – you’re more likely to wear them all the time, you’re more likely to be design / style conscious about them too.

It’s possible too that it’s much more vital that they’re accurate for safety reasons – driving for example.

Anonymous 0 Comments

Far sighted glasses you get off the rack are usually reading glasses. Basically just a pair of magnifying glasses to slap on. Not wear all day.

Anonymous 0 Comments

There are a few reasons for this.

First, farsightedness is much more common than nearsightedness. This means that there is more demand for farsighted glasses, so there are more options available.

Second, farsightedness is easier to correct than nearsightedness. This is because the eye is already able to focus on distant objects, so all that is needed is a lens that will help the eye to focus on closer objects.

Third, nearsightedness is more difficult to correct because the eye is not able to focus on distant objects. This means that a more powerful lens is needed in order to help the eye focus on closer objects.

Fourth, nearsightedness is more likely to cause other problems with vision, such as headaches and eyestrain. This is because the eye is constantly having to work harder to focus on closer objects.

Overall, farsightedness is much easier to correct than nearsightedness, so it is more likely that you will be able to find glasses that will help you see better without having to visit an optometrist.

Anonymous 0 Comments

They both should require an optometrist check to make sure the glasses match your eyesight.

But, the healthcare system being what is, both in terms of cost and availability, it is a better option in the long run to make the most commonly useful prescriptions cheaply available than not at all.

I’ve only ever seen correction glasses offered off-shelves in North America. In Europe and Japan you are ~~required~~ strongly advised/supposed to go see an optometrist or ophthalmologist (in some places, the distinction does not exist).

Anonymous 0 Comments

Around the age of 35, humans’ eye muscles responsible for focusing on near objects deteriorate, so even those born with/live with/got lasik to 20/20 vision will need reading glasses eventually. There doesn’t seem to be an equivalent phenomenon in eye muscles focusing on distant objects.

A new medicine in the form of eye drops has changed this, however, giving many of us over-35s an ability some of us haven’t enjoyed for decades.

Anonymous 0 Comments

The amount of precision required for reading glasses is a lot lower than that required for distance glasses. The reasoning is that you can easily move the object near your face to get better focus, but you can’t really move the world to get better focus.

This is especially true as the focus precision is exponential to distance: around 30 ft/10 m away is basically infinity*, but there is a huge focus difference between 1ft and 1.1ft. This means moving a a few meters closer to an object 40 ft/13 m away will make almost no difference, but moving a book a couple inches/cm will make a huge difference.

That said, optometrists can do a much better job making reading glasses, its just often not worth the extra cost.

* Higher precision is required for some stuff, namely if you have really high magnification. Think telescopes and binoculars.

Anonymous 0 Comments

I went snorkeling once, guide provided masks for near-sighted people, strong and weak, worked great.

Anonymous 0 Comments

The primary reason for why near sighted glasses are prescription only is because of the fact that not everyone’s eyes are the same distance apart. So lenses have to be crafted specifically for the shape of your head to focus the curvature of the lens into your eye. Without this, even with the right prescription, as distance increases, your vision will blur more and you effectively aren’t getting the value of the glasses. The distance doesn’t even have to be that great, can be as little as 20-30 yards where things start to blur. This means simple tasks like driving, become more difficult. Additionally it causes much more eye strain as your eyes are having to focus much more and squint to make out those blurred things, causing headache and eye fatigue. And since you are wearing glasses during all waking hours, it is just all around not good. You could see this yourself by borrowing a friends glasses with a similar prescription. They just won’t work well for you, even if it is exactly the same prescription.

Now compare that to reading glasses where the focus lost from distance is non existent since what you are looking at is only up to a foot or so away, so eye strain and fatigue is pretty much non-existent. Couple this with the fact that you are likely only wearing the reading glasses for a few minutes at a time to read something and then taking them off. If you need to wear full time far sighted glasses, these would be prescription, as you would suffer some of the same things.