Eyeglass prescription?

Question

I had two eye exams within the past year with two different doctors (a optometrist and a ophthalmologist). One last week and another in October. I do not believe my vision has changed much, but the prescriptions are different. I do not know much abut prescriptions. Why are they so different?

October exam

Spherical Cylindrical Axis

OD -7.50 -.50 180

OS -8.00 -.25 125

This month

Spherical Cylindrical Axis

OD -8.50 -1.00 90

OS -8.50 -.1.00 75

Answer 1

I agree with spectacle.... based on the third number in each prescription, you probably neglected to notice that middle number had different signs.  Most optometrists use a minus for the middle sign and most ophthalmologists use a plus sign.  If the second option from October was actually in plus form, the conversion for the OD (right eye) would be:

-7.50 -1.00 x 180 (which is much closer to the example in the first option)  The left would be:  -7.50 -1.00 x 165

They are slightly different, but if you are a very young person it isn't unusual to see changes in as little as six months.

Were you  having trouble with your previous prescription such that it prompted you to have two exams within a year?

Answer 2

You really should ask the doctor that did your most recent exam. They are different, but not that different. Are you shure you got the signs right on the ophthalmologists Rx? They usually write theith with we call Plus cylinder form, which would put your cyl in a + instead of a -. You really should have taken the prior Rx to the new doctor and had them see what the difference would be for you in the phoropter in the office. Not seeing you and not knowing your history, none of us can really tell you what is going on, it could be as simple as your eye changed a bit. IT really is not that much of a big change, it is just a little different. If your first Rx actually has a set of + signs for the Cyl, your rx for the october date would be converted to  -8.00-.50x90 and -8.25-25x35. This would be more consistant with the new exam numbers as you have to write the prescription 90 degrees away and change the sign of the cyl. It is hard to explain but rather simple. They just use different means to get at the same numbers and they then write form a different perspective. I really would make a ltitle appointment with your new doctor and see what they say after seeing the prior one. There are too many variables to be abel to give you a good answer here.