Refraction

[Myopicchild]

Can you get a correct refraction without eye drops? My daughter who is very nearsighted went for her checkup and got measuremen of - 10.25 (left eye) and -9.5 (right eye). The dr (M.D.) didn't dilate her eyes. I went for a second opinion and got -8 in each eye with eye drops.  Are eye drops a must in getting correct refraction measurement in children?

[John C Hagan III, MD, FACS, FAAO]

You thinking is in error.   In England they weigh people in kilograms, in the USA pounds. They measure the same thing.

In algebra its the same thing   10 + 5 = 15  (plus cylinder)
                                             20 - 5 = 15 (minus cylinder).

JCH MD

[Myopicchild]

Thank you very much for your answer. It does mean a lot to me in terms of myopia progression, as my daughter's eye are too long. If they get longer, the retina is more stretched, etc, etc.  However, I don't understand how one dr can get plus cylinders for astigmatism and the other can get a minus reading. In my undeducated opinion, it's either plus or minus, no matter how you look at it. Isn't it similar to nearsightedness versus farsightedness, you are either one or the other.

[John C Hagan III, MD, FACS, FAAO]

I  would go in the future to the Eye MD that dilated your child. In a young child the focus muscle is so strong it interfers with glasses testing and its easy to make the glasses too strong (as is the case with your daughter). The use of drops is called cycloplegia.

By the way you can't tell much about the change as one RX is plus cylinders and one is minus cylinders. Sort of looking at your weight in pounds and in kilograms. They really look different.

The second opinion converted to plus cyclinders to compare with the undilated exam is:

-9.00 cyld  + 1.00 axis 90   OD
-9.25 cyld  + 1.00 axis 90   OS

As explected the undilated is over-minused.

[Myopicchild]

I forgot to add that we also got different readings for astigmatism. Without the eyedrops:

OD - 9.50, cylinder +1.0, axis 90
OS -10.25, cylinder +1.50, axis 85

2nd opinion, with dilation:

OD - 8, cylinder -1.00, axis 180
OS - 8.25, cylinder -1.00, axis 180

I' m really confused with this astigmatism thrown in. If you do the math, the end result is about the same, however, in terms of myopia progression it means that it either didn't progress from 6 months ago with worsening astigmatism, or it did progress by almost 1.75 diopter in each eye. Please advise. My daughter is 4 years old. Thank you in advance.