OT: DVLA

[NY]

My wife got new glasses only a couple of years ago and they produced the "small eyes" effect when I looked at her. OK, she has astigmatism so she needs lenses which are more curved in one plane than the other. Since then, she's had another new pair which look a lot more normal; the optician who gave her those commented on the previous small-eyes ones having "a lot of prism in the prescription". The glass in the old ones was definitely thicker than the frame at the edge and got thinner towards the middle, which is the opposite of my reading glasses which (presumably) have positive dioptre strength.

[Bob Eager]

My left eye was like that (when I had it). Very thick at the edges, far thicker than the frame. So much so compared to the other eye, that the glasses were actually significantly heavier on that side and needed careful adjustment to make sure they didn't tilt to the left!

[NY]

Yes it all comes down to whether it is possible to attach the focussing muscles to the new lens. I'm sure micro-surgery like that will be possible one day, and people will be amazed that at one time a cataract replacement left people with fixed-focus vision.

[Robin]

Accommodative lenses have been around for 10+ years but I've not seen a recent authoritative review of the pros and cons.

[Tim Streater]

I don't see how it can allow accommodation. That works because our our lenses have muscles attached to the edges that pull the lens flatter (or do they push it? damned if I know). When your own lens is replaced with a plastic one, I don't see how they can reattach those muscles.

[Tim Streater]

Nor in TescOS or Boots either, according to their websites. Does anyone have them off-the-shelf where you can just walk in, browse, try them on, and then buy?

[Dave Plowman (News)]

If you really have 'normal' distance vision, you can get ready made specs as a reading aid, and they are very cheap. So lots of pairs left just where you need them. ;-) It's what I do as I wear contact lenses which correct for distance.

[Max Demian]

I remember people with those 'pebble' glasses, presumably operated on before replacement plastic lenses were standard practice for cataract. There was a noticeable extra bulge in the middle of each lens. Of course, these were convex, unlike the 'bottle top' kind for people who are very short sighted.

[Max Demian]

Surely you'd have to take them outside to check them for distance vision. And then your pupils would contract so the fitting would be less accurate. (Eye tests are done in dim light.)

I think you really need a proper eye test at an optician for short sightedness. Then you can choose really cheap glasses if you like, perhaps at a discount dispensing optician or online.

[Jac Brown]

Yes, I am short sighted and my prescriptions are negative diopter values.

[Tim Streater]

I have my prescription, from an eye test done 19/11/2018, to hand: Right -0.75, Left -1.5. It's probably got worse by another 0.25 dioptre both sides since then, as that is what is happening to my sight at the moment.

I'd want to test them for fit as well as for correction. The latter I can do in the store, but I can't do the former online. Cheap glasses like that would be a compromise anyway, since both lenses would have the same correction, so I'd want to test for the best correction compromise at this moment, which I also couldn't do online.

That would probably be good enough, since in 6 months or less they'd need replacing.

[Steve Walker]

Probably not. There was a fuss about stocking reading glasses and allowing people to buy them without an eye test, prescription and checking by an optician. Distance glasses, which might be used for driving are likely to be considered a step too far.

SteveW

[Steve Walker]

All muscles can only pull I think. They contract in length (thicken in the middle) when they work and can be stretched back out by opposing muscles or springy tendons or the like when they relax.

I don't know if they can, but there are certainly multi-focal lenses (giving near, middle and distance vision) and I'm sure I read of a new type of lense giving a full range, but I have no idea how they work.

SteveW

[The Natural Philosopher]

How does an optician test your eyes?

By trying various lenses to see if you can see better.

How does a person select reading glasses?

By trying various lenses to see if you can see better.

It's staggering how much difference an expert in a white coat makes...

[Max Demian]

a) Your eyes may need different strengths of lens. b) You may have astigmatism requiring a cylindrical component to the lens - most people do, and it's corrected at the same time as correcting for other faults. c) Shops are usually too brightly lit to select the best strength - your pupils contract increasing depth of focus. d) A skilled optometrist can look in your eyes and check for eye - and some other - diseases.

Having said that, I don't see why you shouldn't buy reading glasses over the counter after your prescription has been determined by the initial test if your eyes require the same strength.

I've yet to see an optician in a white coat.

[The Natural Philosopher]

that will mean you cant find a set that suit you perfectly.

Goly. and looking at a brightly lit board on numbers with black letters in sin;t?

And how many are that skilled?

It wasnt an optician that told me amything about my eyes except astigmatism.

You should have gone to spec savers.

[dennis]

They have multiple segments that focus on different distances. A bit like varifocals but each segment covers the whole field of view.

They reduce the contrast in the image so they may not be the best thing to have.

[Terry Casey]

Don't have to be.

Buy two identical pairs but different strengths and swap one lens fom one pair with the other.

Throw away the pair with the reversed lenses and wear the other pair.

At the low prices that you can buy them for, it would still be a very cost effective solution.

[Terry Casey]

I think these first appeared in the interval between my two cataract ops, so no good for me because you need a matching pair!

Also, very expensive, if I recall correctly.

Could be a saving in the long run though.

[Roger Hayter]

You can buy fairly cheap glasses on the Internet to a prescription that you provide. You need, for best results, to know your interocular distance; try to read it over your optometrist's shoulder, as they tend to keep it secret for obvious reasons. It takes a measure of skill to estimate it.