What Would My Contact Lens Prescription Be Approximately?
September 26, 2009 by admin
Filed under FAQ on advance for astigmatism
Here is my particular situation. 1. I am disabled and cannot spend much time on the computer, so there’s only so much research I can do on my own. 2. Because of my disability, my financial resources are limited. 3. I recently went to an eye doctor and had a full eye exam. I didn’t find out until after the exam that he does not do contact lens prescriptions. Now here is an interesting part of the story…. 4. I only need the contacts long enough to try on eyeglasses and see how they look! I do not want someone choosing them for me. I do not want to pay another fee and have another exam…. So, I found some sites that will fill a request for contacts without verifying it with the doctor. But this is the other thing I need, if possible: I know nothing about vision prescriptions. I need at least a ballpark prescription to submit in order to get the lenses. I can tell you that I have been nearsighted since 3rd grade (I am now 53 years old). I also have astigmatism. Not sure if it is in one or both eyes. I’m sure it’s in my right eye — referring to astigmatism. I’m kinda sure it’s in both. I wear progressive lenses and my brand new prescription is as follows: DISTANCE: O.D.: SPHERICAL: -875 CYLINDRICAL: +075 AXIS: 138
O.S.: SPHERICAL: -1100 CYLINDRICAL: +100 AXIS: 071
READING: O.D.: +200 O.S.: +200 I don’t know if any of that information would help you to supply an educated guess as to a contact lens prescription that I could get that would just allow me to wear them long enough to pick out some glasses and see well enough to do so. The prescription doesn’t have to be exact. I don’t want to hurt my eyes, but I also don’t want to waste over $100 going to another doctor and then ordering a package of toric lenses. Can anyone out there help me? If so, please indicate exactly how to express the prescription. I am wondering if perhaps I don’t need the toric. Could I get away with regular ones? I have just typed here what is on my prescription for glasses, but I’m sure that a contact lens prescription is expressed completely differently. Please do not answer unless you actually have relevant information to my question. Thanks much!
Okay, so here’s your prescription:
OD -8.75 +0.75 x 138 add +2.00
OS -11.00 +1.00 x 071 add +2.00
Two problems with that. One, you’re wearing progressive lenses, and it’s going to be pretty difficult to fit you with multifocal contacts, so if you were to get contacts you’d probably need reading glasses (even just the cheap non-Rx ones from the pharmacy) to see clearly up close. Multifocal contacts exist but there’s too much variability to guess at what Rx you need without having you see a doctor. Two, it’s written in “plus cylinder” form, and if you’re looking to order online you’d need “minus cylinder” form. (Ophthalmologists in certain countries use plus cyl; most other countries and all optical companies use minus cyl.) We can convert that without any major issues.
So, hypothetically, you just want lenses to try out so you can pick out some new glasses? You could try going to the glasses place and ask them if they could throw something on in roughly your prescription just for that purpose — when they see your prescription, they’ll know just how blind you are without correction! We use daily lenses for this sometimes, because they’re disposable anyway.
You do have astigmatism in both eyes (that’s what the cylinder number is), but usually we can get away with not correcting it if it’s under 1.00D. Yours is, so I’d probably try spherical (non-toric) lenses first. To figure out the contact lens prescription from that, let’s convert your glasses script to minus cyl:
OD -8.00 -0.75 x048 add +2.00
OS -10.00 -1.00 x161 add +2.00
And now to convert that to just sphere:
OD -8.37 add +2.00
OS -10.50 add +2.00
And now to ‘vertex’ it — i.e. correct for the fact that contact lenses sit on your eyeball and not a centimeter away like glasses do:
OD -7.50 add +2.00
OS -9.00 add +2.00
So that’s what you’d be looking at for a contact lens prescription. The other parts of it — diameter, base curve, etc — are all based on how the lenses fit on your eye. Without doing extra measurements and tests — that’s what the extra appointment is for! — there’s no way of telling you which brand of lenses in which size is going to work.
And the “add” (or “reading”) part of the prescription doesn’t go into the contacts; that’s the power of over-the-counter reading glasses you’d need to see clearly up close over top of the distance-prescription contacts.
If you want to order contact lenses only so you can choose your eyeglasses what you should do is order contacts that are -8.5 for you O.D. and -10.50 for you O.S. you should be able to see clear enough to choose your own pair of eyeglasses. Contact lenses might be tricky though, if you have never wore contacts before, you don’t know your base curve or the diameter of your eyes so the contact lenses might not sit in your eyes properly. You will still be able to see but you might not be able to have them for too long. if you want to order contact lenses try lensway.com I normally get contacts from them. Just a thought, if you decide to do this, maybe you can save some money and get good contacts for one eye only and use them on both eyes…get -8.5 contacts and you still be able to see a little with the other eye. I really hope this helps and I wish you luck.
Have someone take digital pictures of you trying on frames.
Play them back on your computer with your glasses on.
You’ll be able to choose.
Don’t waste money on the wrong contacts for just one day’s use.
Hilbert is right. So for close up you would need -.5.50, -7.00.
Why not try just a -5.50 in one eye or both eyes for looking in a mirror. You do not need toric lenses. Just buy or borrow 1 lens. this will let you see.
Use a lens with a small radius base curve.
You probably should be wearing contacts.
hiya
i’m not sure if it’s the same where you are, but many opticians round where i live (uk) do free contact trials – so you could see if any opticians around you offer this kind of free trial