OT: Reading glasses and prescriptions

[Mike Barnes]

The other thread on reading glasses is very interesting. There's obviously knowledge in this group (of course!). Here's a harder question. I've spent some time searching the web for information about what the numbers on my prescription mean but I've gone about as far as I can and would appreciate some confirmation that I'm thinking along the right lines.

My prescription calls for small corrections for distance and astigmatism (R SPH +0.75 CYL -0.50, L SPH +0.50 CYL -0.50). That correction is apparently too slight to warrant glasses for distance, and I've always been very happy with my uncorrected distance vision.

But for nearly 20 years I've needed reading glasses. My prescription specifies ADD +1.75 for near sight in addition to the long sight correction. In practice that would actually be far too much. After some experimentation I've settled on +1.50 off-the-shelf reading glasses, which give me clear vision over the range of distances that I actually want for reading and computer use.

On t'Internet you can get glasses made to your exact prescription for very little money nowadays, so I'd like to give it a go. But my prescription as it stands is obviously far too strong so I need to adjust it. I want something that gives me the same range of reading distances as my +1.50 ready-mades, but also incorporates the distance corrections in my prescription.

I think I need to preserve the 0.25 difference in the spherical correction. Also since the +0.50 cylinder correction is only on one axis it seem equivalent "on average" to +0.25 spherical correction. I have to do some rounding so I'll go for stronger rather than weaker on the assumption that my eyes aren't going to be getting any better. The result is:

R SPH +2.00 CYL -0.50 L SPH +1.75 CYL -0.50

(plus the axes which I haven't bothered to include here).

I'm happy just to put in an order like that and see how they work out, but I'd also like to improve my understanding of how these things work. Unfortunately my optician (like many opticians, and for entirely understandable reasons) prefers to keep her knowledge to herself and sell me very expensive glasses. So - any comments?

This being uk.d-i-y I suppose I really ought to make the lenses myself with an angle grinder, but I'll take things one step at a time. :-)

[Matty F]

I found that the process for having my eyes tested was a lengthy and hit and miss affair. I'm not confident that the right result was reached. My optician didn't offer to give me a copy of the prescription, and wanted to sell me glasses over eight times the price of Chinese ones ordered oner the Net. Which are excellent, by the way.

While looking at my bill I discovered that if I rotated the bill while looking at a solid line on it, I could check the angle of my astigmatism. I reckon I could invent a way of working out my own prescription.

[Mike Barnes]

The first time I had my eyes tested the result was miles out, for sure.

But now I have them tested every two years and although the results vary slightly, there's enough consistency to make me confident of the results.

I thought the optician was *required* to give you a copy of the prescription. They're not required to disclose your pupil separation, but that's easy enough to DIY.

I'm sure people would be interested. But note that opticians also carry out a health check, which is important and probably not DIY-able.

[Bob Eager]

My wife had her eyes tested by the local optician a few weeks ago, and upgraded the lenses in her old specs (2 pairs). Never asked for a prescription.

She's now realised an extra pair or two would be handy, so she sent them a note and an SAE (they're hard to get to for the next few weeks). She received a rapid response, printed prescription, and scribbled across it: "For information only".

Presumably arse-covering?

[Pete Zahut]

My left eye is what they call a 'lazy' eye. I was told that it does actually work and it is actually seeing things but after about three, maybe five seconds or so it decides it's had enough or it's bored and loses interest, so decides to do something else. It's a really weird thing to describe and I just haven't got the words to tell the optician what's going on during my eye test, especially when they put the test frames on you and say, "Is it better with lens 1, or lens 2? Is the red circle sharper or the green circle?"

My reply is always, "I don't know" because by the time I've focussed on the board my eye has lost interest and everything just looks blurred. How can you get an accurate idea of what lens that eye needs under those conditions?

They diagnosed my lazy eye when I was 14 back in 1972 and I can't remember if they tried to fix it and it didn't work, or if they just didn't do much about it but I've been told that it's been like that for so long now that, even though they have the technology to do something now, they're not going to because it would cause more problems than it would cure.

Here in the UK you're right but Matty's in New Zealand where things may be different.

[Peter Crosland]

If you had an NHS eye test the optician is legally obliged to give you a copy of the prescription.

Peter Crosland

[<me9]

I have a 'lazy' right eye.

Mine never seems to do anything but occasionally gives double vision.

I tell them the same but they still seem to adjust the figure they (or these days the automatic machine) get on refraction. I've always been amazed as to how clear the refraction figure is.

By shining a light in and putting lenses in front until what coes out is similarly in/out of focus to what is going in, AKA 'refraction'

Mine was like that certainly from age 6 (in 1952)(I can't remember much before) but I was wearing glasses from age 2½. 2 of my 4 children also had a suspect lazy eye, but were both sorted by patching.

I find I can't read(unless hugh print in peripheral vision) but the eye gives useful 3D vision. Central vision is blanked out by my brain as it (without glasses -- severe astigmatism and myopia) can't be reconciled with what the other eye sees.

I was told at one time that if I lost sight of my other eye the poor one would recover, but I'm not racing into laser surgery as I know of at least one failure (corrected fortunately but at great expense in harley street). Failure wit h me could result in little sight.

[Derek Geldard]

I'd been doing the same but at 64 had to have a sight test because of incipient diabetes and the optician warned me my vision with supermarket reading glasses was marginal for driving. You can't mess with these guys they could report you to the DVLA if you continue to drive whilst your vision is not good enough for driving.

Complicated info snipped ...

I just got glasses direct to make me 2 pairs of specs, one set for distance one for what I (laughingly) call "working at the computer" (Don't like multi focus / continuously variable lenses). I'd worked out for myself that my standard prescription reading glasses were in focus at 25 cms but my netbook screen is nearer 40. A quick word with their optician got me what I want at their standard price in 3-5 days. It seems that many / most internet spec suppliers will do the same. Glassesme.com has prescription specs from £8.70.

OTOH cheap spec frames make you look a Frump.

Derek