Anyone know about prescriptions for your eyes?
Discussion
Went to specsavers at the start of the year, and they gave me a copy of the prescription after the eye test.
They put:
R SPH -1.25
L SPH -1.50
Axis 20.0
CYL R - -0.50
Anyway, broke my glasses last week and decided to orde rto some contact lenses. Ordered -1.25 for the R and -1.50 for the L.
Problem is, the R was all blurry and I couldnt see s
t. I started getting a headache and my vision was out of focus.
So, i popped one of the -1.50's in both eyes and it was fine straight away.
Im going to order some glasses off the internet because they are cheaper. Based on the contact lense experiance, will i be better ordering both eye glasses at -1.50?
They put:
R SPH -1.25
L SPH -1.50
Axis 20.0
CYL R - -0.50
Anyway, broke my glasses last week and decided to orde rto some contact lenses. Ordered -1.25 for the R and -1.50 for the L.
Problem is, the R was all blurry and I couldnt see s
t. I started getting a headache and my vision was out of focus.So, i popped one of the -1.50's in both eyes and it was fine straight away.
Im going to order some glasses off the internet because they are cheaper. Based on the contact lense experiance, will i be better ordering both eye glasses at -1.50?
fjord said:
Went to specsavers at the start of the year, and they gave me a copy of the prescription after the eye test.
They put:
R SPH -1.25
L SPH -1.50
Axis 20.0
CYL R - -0.50
Anyway, broke my glasses last week and decided to orde rto some contact lenses. Ordered -1.25 for the R and -1.50 for the L.
Problem is, the R was all blurry and I couldnt see st. I started getting a headache and my vision was out of focus.
So, i popped one of the -1.50's in both eyes and it was fine straight away.
Im going to order some glasses off the internet because they are cheaper. Based on the contact lense experiance, will i be better ordering both eye glasses at -1.50?
Contact lenses don't need to be as strong as your glasses prescription because they are closer to your eyeball.They put:
R SPH -1.25
L SPH -1.50
Axis 20.0
CYL R - -0.50
Anyway, broke my glasses last week and decided to orde rto some contact lenses. Ordered -1.25 for the R and -1.50 for the L.
Problem is, the R was all blurry and I couldnt see s
t. I started getting a headache and my vision was out of focus.So, i popped one of the -1.50's in both eyes and it was fine straight away.
Im going to order some glasses off the internet because they are cheaper. Based on the contact lense experiance, will i be better ordering both eye glasses at -1.50?
I'd really go and find a grownup if you fancy contact lenses - eyeballs don't grow back and you only get two...
fjord said:
Went to specsavers at the start of the year, and they gave me a copy of the prescription after the eye test.
They put:
R SPH -1.25
L SPH -1.50
Axis 20.0
CYL R - -0.50
See: http://www.webmd.boots.com/eye-health/guide/unders...They put:
R SPH -1.25
L SPH -1.50
Axis 20.0
CYL R - -0.50
You are mildly short sighted with an astigmatism.
You will need a different prescription for contact lenses to those for your glasses, because they are on your eye as opposed to hovering over it.
Sounds like you have an astigmatism too, but I'm sure our friendly Optition & Optometrist or even the Ophthalmologist (whose names I've completely forgotten
) will be along shortly
Sounds like you have an astigmatism too, but I'm sure our friendly Optition & Optometrist or even the Ophthalmologist (whose names I've completely forgotten
) will be along shortlycwis said:
Contact lenses don't need to be as strong as your glasses prescription because they are closer to your eyeball.
I'd really go and find a grownup if you fancy contact lenses - eyeballs don't grow back and you only get two...
So why does the weaker lense work worse than the stronger -1.50 lense?I'd really go and find a grownup if you fancy contact lenses - eyeballs don't grow back and you only get two...
fjord said:
So why does the weaker lense work worse than the stronger -1.50 lense?
Because it's partially correcting/masking your astigmatism. It's apparently a common trick used if toric contact lenses (which do properly correct astigmatism) are not available or suitable for whatever reason. Increase the power of the prescription slightly and it sharpens the resulting vision.
cwis said:
Contact lenses don't need to be as strong as your glasses prescription because they are closer to your eyeball.
I'm sorry but I call BS on this one.Maybe it's just your wording that's throwing me.
The "SPH" numbers should be the same for both contacts and glasses, to say they don't need to be as strong is wrong in terms of these numbers.
For example, if you had contacts and glasses both correct for your vision (say -1.50) and held them an inch from your eye, the glasses would provide the correct prescription and the contacts would not. However we are assuming both methods of correction are being used correctly so a -1.50 contact in your eye would provide the same correction as a -1.50 glasses lens sat in front of your eye.
OP - cwis is right about your astigmatism though. The "standard" correction you need across your right eye is -1.25. However at a 20 degree angle there is an area of your right eye that is slightly worse than the rest of it. Wearing the stronger lens helps to correct this but also won't be perfect as it will be "over-correcting" the rest of the eye.
The corneal topography machine they used as part of my laser eye surgery showed it to me best. Images like this:
From how it was explained to me the green/blue area averages at around -1.25 in your right eye. However the red areas (in this case at 90 degrees, in your case at 20) is slightly worse.
samdale said:
I'm sorry but I call BS on this one.
Maybe it's just your wording that's throwing me.
The "SPH" numbers should be the same for both contacts and glasses, to say they don't need to be as strong is wrong in terms of these numbers.
For example, if you had contacts and glasses both correct for your vision (say -1.50) and held them an inch from your eye, the glasses would provide the correct prescription and the contacts would not. However we are assuming both methods of correction are being used correctly so a -1.50 contact in your eye would provide the same correction as a -1.50 glasses lens sat in front of your eye.
OP - cwis is right about your astigmatism though. The "standard" correction you need across your right eye is -1.25. However at a 20 degree angle there is an area of your right eye that is slightly worse than the rest of it. Wearing the stronger lens helps to correct this but also won't be perfect as it will be "over-correcting" the rest of the eye.
The corneal topography machine they used as part of my laser eye surgery showed it to me best. Images like this:
From how it was explained to me the green/blue area averages at around -1.25 in your right eye. However the red areas (in this case at 90 degrees, in your case at 20) is slightly worse.
Thanks for the picture and your input. I think i need to get my arse to the opticians and start from scratch with contact lenses.Maybe it's just your wording that's throwing me.
The "SPH" numbers should be the same for both contacts and glasses, to say they don't need to be as strong is wrong in terms of these numbers.
For example, if you had contacts and glasses both correct for your vision (say -1.50) and held them an inch from your eye, the glasses would provide the correct prescription and the contacts would not. However we are assuming both methods of correction are being used correctly so a -1.50 contact in your eye would provide the same correction as a -1.50 glasses lens sat in front of your eye.
OP - cwis is right about your astigmatism though. The "standard" correction you need across your right eye is -1.25. However at a 20 degree angle there is an area of your right eye that is slightly worse than the rest of it. Wearing the stronger lens helps to correct this but also won't be perfect as it will be "over-correcting" the rest of the eye.
The corneal topography machine they used as part of my laser eye surgery showed it to me best. Images like this:
From how it was explained to me the green/blue area averages at around -1.25 in your right eye. However the red areas (in this case at 90 degrees, in your case at 20) is slightly worse.
On a similar note, how did you find laser surgery? its something ive always considered, but been warey of. Having someone pew pew lazers into mah eyes and having no way of altering it back is a little disconcerting.
samdale said:
I'm sorry but I call BS on this one.
You call BS? How rude.A quick Google gets me:
http://www.allaboutvision.com/contacts/faq/cls-vs-...
It's been 20 odd years since I completed my physics degree but I think i could probably still work it out from first principles if I had to.
Glad to hear you're seeking professional help OP.
As someone who had laser surgery and didn't have an amazing outcome I'd offer the following advice - drive your car into the setting sun with a dirty windscreen. Now try driving it at night with cars coming the other way.
Those smears, halo effects, loss of contrast, star bursts etc you get with a mucky windscreen are similar to the effects of a less than optimal result from laser eye surgery. It's rare, and becoming rarer, but have a think how it could change your life.
You can clean your windscreen, and your specs, and change the prescription of your glasses in an hour in town - bit tricky to change your cornea currently however.
Edited by cwis on Wednesday 3rd July 00:06
The physics and the shape required at a specific distance are not what I'm arguing here.
You said the prescription should be different. This is wrong.
I'm saying the prescription will be the same, but the shape of lens required to achieve this prescription will differ.
Both my contact lenses and glasses have the same "strength" in diopters (expressed as SPH for glasses, PWR for lenses) and the same astigmatism correction (CYL, AXIS)
The numbers on the prescription refer to overall vision correction when in place NOT the magnifying power of the lens at a set distance. I can see what you're saying but you're thinking of the pure physics of what's happening to the light in the lens not the overall effect of the vision correction.
You said the prescription should be different. This is wrong.
I'm saying the prescription will be the same, but the shape of lens required to achieve this prescription will differ.
Both my contact lenses and glasses have the same "strength" in diopters (expressed as SPH for glasses, PWR for lenses) and the same astigmatism correction (CYL, AXIS)
The numbers on the prescription refer to overall vision correction when in place NOT the magnifying power of the lens at a set distance. I can see what you're saying but you're thinking of the pure physics of what's happening to the light in the lens not the overall effect of the vision correction.
fjord said:
On a similar note, how did you find laser surgery? its something ive always considered, but been warey of. Having someone pew pew lazers into mah eyes and having no way of altering it back is a little disconcerting.
If you've got the time, have a read of thisThere's a bloke posting on there with the username "968", he knows his s
t and has been very helpful in answering as many questions as possible.Everywhere I've seen that offers laser eye surgery offers free consultations. Head to your nearest one and book yourself in. There's no obligation to book and you can ask as many questions as like. They'll also give you an idea of the cost which may vary with your prescription. Then tot up the amount you'll spend on glasses in the next few years and it even starts to make financial sense.
It was a bit of a no brainer. I hate contacts and can't wear glasses and play rugby.
The only thing I wasn't warned about was the smell of burning cornea, basically the smell of burning hair. Apart from that it was a breeze, just lay back and watch the light show.
samdale said:
The physics and the shape required at a specific distance are not what I'm arguing here.
You said the prescription should be different. This is wrong.
I'm saying the prescription will be the same, but the shape of lens required to achieve this prescription will differ.
Both my contact lenses and glasses have the same "strength" in diopters (expressed as SPH for glasses, PWR for lenses) and the same astigmatism correction (CYL, AXIS)
The numbers on the prescription refer to overall vision correction when in place NOT the magnifying power of the lens at a set distance. I can see what you're saying but you're thinking of the pure physics of what's happening to the light in the lens not the overall effect of the vision correction.
I'm saying the prescription will differ, and the stronger the prescription, the more it differs.You said the prescription should be different. This is wrong.
I'm saying the prescription will be the same, but the shape of lens required to achieve this prescription will differ.
Both my contact lenses and glasses have the same "strength" in diopters (expressed as SPH for glasses, PWR for lenses) and the same astigmatism correction (CYL, AXIS)
The numbers on the prescription refer to overall vision correction when in place NOT the magnifying power of the lens at a set distance. I can see what you're saying but you're thinking of the pure physics of what's happening to the light in the lens not the overall effect of the vision correction.
Did you look at the link I posted?
If your (you, personally) prescription is not very strong (ie low SPH number) it may be that the increments of strength that contact lenses are available in means that you, personally, have the same prescription for both contact lenses and glasses.
Don't make the mistake in assuming this applies to all cases.
And if you do, don't persist in your error when someone actually posts a link proving you're wrong!
Just for your interest, I have glasses and contact lenses, and the prescription is different.
I asked my optician (as I thought they'd made a mistake) and he explained exactly what I have, and exactly what I've posted in the link above, and also what another poster has posted in this thread!
But if you want to persist in believing something that has been proved wrong, carry on. I'm leaving it here. I'd suggest however that before you proffer advice on something, you actually know what you're talking about in the first place.
cwis said:
I'm saying the prescription will differ, and the stronger the prescription, the more it differs.
Did you look at the link I posted?
If your (you, personally) prescription is not very strong (ie low SPH number) it may be that the increments of strength that contact lenses are available in means that you, personally, have the same prescription for both contact lenses and glasses.
Don't make the mistake in assuming this applies to all cases.
And if you do, don't persist in your error when someone actually posts a link proving you're wrong!
Just for your interest, I have glasses and contact lenses, and the prescription is different.
I asked my optician (as I thought they'd made a mistake) and he explained exactly what I have, and exactly what I've posted in the link above, and also what another poster has posted in this thread!
But if you want to persist in believing something that has been proved wrong, carry on. I'm leaving it here. I'd suggest however that before you proffer advice on something, you actually know what you're talking about in the first place.
Honestly, I didn't know they could be different, my mistake. Your link mentions it in one line with no real explanation as to why or whether it would be stronger or weaker.Did you look at the link I posted?
If your (you, personally) prescription is not very strong (ie low SPH number) it may be that the increments of strength that contact lenses are available in means that you, personally, have the same prescription for both contact lenses and glasses.
Don't make the mistake in assuming this applies to all cases.
And if you do, don't persist in your error when someone actually posts a link proving you're wrong!
Just for your interest, I have glasses and contact lenses, and the prescription is different.
I asked my optician (as I thought they'd made a mistake) and he explained exactly what I have, and exactly what I've posted in the link above, and also what another poster has posted in this thread!
But if you want to persist in believing something that has been proved wrong, carry on. I'm leaving it here. I'd suggest however that before you proffer advice on something, you actually know what you're talking about in the first place.
However the first thing I commented on was your absolute statement saying they don't need to be as strong. Even your article only goes as far as to say "may" be different not "definitely will be less than". This came across as a physicist explaining lenses rather than a person talking about eyes.
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