Glasses prescription question

tenchi-fan · 15 Oct 2006 at 18:07

My prescription is currently -2.25, -2. I'm short-sighted. (and 24 years old)
Today I went to Dublin for a free consultation on laser eye surgery.

[you can skip this next bit if you don't need a background!]

He checked my prescription and found it to be fine. Then he checked my eyes in a machine (you know the one that shows the hot air balloon). Then another machine with a purple light. Then a machine with a red laser. Then he put drops in my eyes to numb them so he could measure the pressure of my cornea or something. Then he put yellow dye into my eyes and shone a UV light into them... at this stage he said I was an ideal candidate for laser surgery and was all but ready to arrange an appointment.

Finally he put more drops in that caused my pupils to dilate. He checked my prescription again, and found that I only needed -1, -0.75 (obviously it's not possible to go around with huge pupils, a splitting headache and poor vision for reading!). He said that my current prescription may be too strong but I wouldn't be able to see without it because my eyes are too used to it.

[/skip... ok here's the important bit coming up]

Long story short, I will have to wait at least 6 months but possibly as long as 5 years for my prescription to "balance out".

I'm confused by the measure used. My prescription is -2.25, -2. To be in the police "The vision standard requirement is Binocular Vision of not less than 6/9, 6/12 unaided by glasses or contact lenses."

Are the -2.25 and the 6/12 comparible? Or is there a way to convert my vision to whatever scale is used by the police?

Vixen · 15 Oct 2006 at 18:28

Go to another optician and get them checked again. Glasses don't make your eyes worse, they are just more relaxed because the muscles aren't straining to see things.
I had my eyes tested last year and was told that my sight had improved from the last test, despite the fact I'd gone in because I felt I could see a lot less even with my glasses on. I didn't dispute it at the time because I thought an optician should get it right. I then found out this summer that my eyes were actually 0.5/0.75 worse than the glasses I was wearing, and my sight felt like it was still the same. This time around I went to two different places to check it

.

It's possible that your initial test for the glasses you are wearing was wrong, but you'd know as soon as you put them on the first time if they weren't right for you. My boyfriends glasses are 0.5 different from my new ones and I can barely see anything in them. Either way though, get the test re-done.

tenchi-fan · 15 Oct 2006 at 18:58

Vixen said:
It's possible that your initial test for the glasses you are wearing was wrong, but you'd know as soon as you put them on the first time if they weren't right for you. My boyfriends glasses are 0.5 different from my new ones and I can barely see anything in them. Either way though, get the test re-done.

Last two times I went to specsavers because they have nice frames and do good deals. This time I think I'll go to a longer-established opticians in town who has a really good reputation.

My old prescription was -1.75, -2.25 and I felt it was perfectly fine.

In specsavers they were trying loads of different lenses and I kept saying they weren't making much of a difference, although when making the decision on which was better I always picked the lense that made the writing appear blacker (although there really wasn't much difference at all).

The optician today said it's common for people to base the decision on whether the text appears blacker and he said this causes people to end up with too strong a prescription. However, your eyes quickly adjust to the stronger prescription until you actually need the strong prescription to see.

If this is the case, I'm pretty disgusted with specsavers as I was very firm in telling them there was little difference but they insisted on giving me stronger lenses.

My current prescription is -2.25, -2, which means my eyesight in my left eye "worsened" by -0.5. When I tried on the glasses however I felt the left eye was far too strong and caused a bit of a strain for the first day until I got used to it.

Now today I found out my "real" prescription is -1, -0.75 and part of the reason for the discrepency is the insistence of (apparently) newly qualified opticians to recommend stronger lenses on each visit.

Blinkz · 15 Oct 2006 at 19:37

-2.25 and 6/12 aren't comparible. -2.25 is the strength of the correction that your glasses are, 6/12 is a measure of what you can actaully see. For example I have -2.25 and -1.75 and I can see 6/6 binocular, which is the UK equivlent of 20/20. However someone may have the same correction but may not be able to see as much eg may only get 6/8, (or better 6/5). Most corrections should get you to close to 6/6, which is considered normal vision.