CM measurement and glasses

Hello, I have the eyesight of -9.5 (right), -12 (left) as per optometrist, but when I measure from CM measurement provided in end myopia website, I have -8 (right), -11 (left), should I buy my glasses as per cm measurement? Pls help I’m confused. By the way I feel like my eye sight is getting better.

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cm measurement to blur is from your eye = contact lens prescription (vertex distance of 0)
use the vertex distance formula to convert to glasses and you might find you have what you expect

I’m still learning as well, but from what I’ve gathered in my own research is that cm measurements are primarily used for tracking your progress and determining when its time to make changes. After adjusting for vertex distance, cm measurements will give you a baseline that will map pretty closely to your distance prescription at a particular light level. However, that may not be your ideal glasses prescription. That is, you may need tweaks to make it work for you, particularly if you have astigmatism, etc.

For example, I find that my cm measurement (I usually take the measurements using my desk lamp light) plus astigmatism correction will get me to 20/30 or so on my 6m Snellen chart under artificial indoor lighting. I can hit 20/20 with that prescription in sunlight, but I need about -0.5 diopters of additional sphere correction to hit 20/20 in artificial indoor lighting.

Then again, I have a trial/test lens set which allows me to experiment and dial in the numbers that work best for my eyes. So, your experience may differ.

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This is going to be a great journey. My eyes do better with contacts so found a source to order my own which was so freeing. After years of feeling the optometrist had “control” of my eyes. @jakey I will be in this Forum a lot more in the upcoming weeks. I was still trying to get all the info I could from this class and the The Guide and You Tube. I still am not getting any blur to distance at close up so I need to figure that out but have new contacts at 0.25 diopters lower arriving this weekend and am super excited to be able to work the distance active focus at least with those . I can see it working already with the 0.25 reading glasses I have.
I still felt off using higher reading glasses like +1.25 so wanted to now overdo per the advice to work down slowly. Merry christmas- excited for tomorrows lesson!

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