Prescription Question

[christianirc]

I know you don't make glasses, but I was hoping you could help me anyway.  I'm blind in my right eye, and I need single vision lenses for my left.  I got a new prescription (From the MD who checks me once a year), had it made at a place that specializes in glasses in the mall.  With those,  I could see out of one small point in the center, but everything else was blurry.  After verifying that the lenses were correct, I went back to the MD who changed the prescription.  They said it was a considerable change... from 7.25 to 8.50 they were both +3.25 x090.  I'm having the same problem with these glasses.  I can see through a small point in the middle, but anywhere out from that point is not only blurry, but items arch.  Like a straight window looks curved.  Since I am blind in the right eye, is it possible to get the whole lens to be the prescription?  I'm sure it was in my last pair of glasses were  4 years ago.

Could I be doing the exam wrong?  I have such a hard time telling which is better, 1 or 2.  Last time he did something that made half the chart red and half green.  The green was clear and he told me to tell him when the red got clear.  That told him that my prescription was too weak.

I've now spent $350 on glasses and can't seem to get them right.  The eye place won't make them again without charging and I had to save a couple months to get these.  I would appreciate any help you could give me.
Brenda

[Forum-OD-MP]

'is it possible to get the whole lens to be the prescription?'

in theory the 'whole lens' of every single vision lens is the prescription.  something is wrong with one or more of the following:

1) Rx
2) base curvature
3) material
4) center placement

'Could I be doing the exam wrong?'

no.

if you have your old glasses, we could learn a lot from those.  we need to find out what the rx is, what the material is (cr-39, polycarbonate, hi index, etc), where the optical center of the rx is and what the base curve is.  in the new glasses it would be best if we matched the base curve, material, and center placement as closely as possible.

as far as the Rx is concerned, you may need a second opinion.  people perform refraction a lot of different ways, and some are better than others, and some are more aggressive/conservative than others.  if might help if next time someone else did the refraction

[aimee37]

Thank you,
I've moved to another state since my last pair of glasses 4 years ago.  I called to see if I could get the info about them, but they refused to give it to me saying the prescription expired.  I'm sure the lenses weren't anything special, they were much heavier than these.  Whatever medicaid pays for, I had medicaid at the time.  I mainly got these because those were so scratched up I couldn't see through them well anymore.

[aimee37]

you just answered one of the questions.  almost all medicaid glasses are made of cr-39 b/c its inexpensive.  it is heavy in larger rx's like yours and is easily scratched.

BUT!

cr-39 has good optical quality.  really good.

polycarbonate, which is a really common material for use in high rx's, DOES NOT usually have great optical quality.  it makes the lenses thinner, lighter and more durable than cr-39, but usually has POORER optical quality than cr-39.

you should be able to get the info about your old glasses if you tell them your story.  tell them you are having rx/glasses problems and you want to compare the numbers and material, etc.  tell them to fax you an rx that has "EXPIRED" written on in...you dont want to fill it, you just want to compare it to your new glasses.

[aimee37]

Well, I just called them and they still refused any information.  

I am willing to put up with them being more easily scratched and heavier, if I can see through the whole lens.  I will take these new frames to the eye doctor and see if I can purchase new lenses from them.  My last questions... and I really appreciate your help, you have saved me a LOT of money and time.  

1.  Tell them I want the cr-39, correct?
2.  My eyes were measured at 62mm.  But since I use only the one eye, should the optical center be different than most?
3.  I never knew my prescription was high.  I started wearing glasses when I was about 12 (I'm 32).  Should I be concerned about it being that high now and can it go higher, or will I have to put up with less than 20/20 vision with glasses in the future?

Thanks, and I will quit bugging you.  Thank you for what you do, you have been helpful beyond what I can express!

Brenda

[aimee37]

anything over about -6.00 or +4.00 I personally consider "high".  high enough to possibly worry about the thickness of the lens, anyway.

anything more than about 2.50 diopters of astigmatism i personally consider "high" as well.  you say that you are 3.25 astigmatism.

none of that is a big deal, tho.

if the glasses that you DONT like are made of polycarbonate, then yes, you probably need some other material IMO.  cr-39 (a lot of people call this "plastic") is cheap and has good optical quality...it just wont be very thin & light in your Rx, and is more easily scratched than poly.

you could also have a mid index plastic or a hi index plastic.  both of those would be better optics than poly, but more expensive than cr-39.  cr-39 is very inexpensive.

the most accurate measurement for a one-eyed person is a MONOCULAR pd.  ask the optical to take a "monocular" pd...they can do it.  (pd is "pupilary distance"...the distance between the eyes)

"Should I be concerned about it being that high now and can it go higher, or will I have to put up with less than 20/20 vision with glasses in the future?"

no, you should not be concerned, and no you will likely not have to put up with less than 20/20.  both of those are highly unlikely, assuming you are getting regular eye care.