Eye chart vs cm

My eye chart reading has been steadily improving to the point where I can read the 20/20 line with my 2.5m chart and 20/25 line with my 4.5m chart that’s with both eyes. This has been consistent for 2~3 weeks now.

I am also not getting much challenge with my normalized.

Yet my cm measurements has been stagnant for over 3 months. If I go by the cm measurements, I really shouldn’t be able to read the eye charts since it’s almost a full diopter higher.

Anyone has this before? What should I do?


do your CM measurements match your eyechart measurements?
Like did your eyechart measurements “catch up” to your CM measurement?

No. It doesn’t catch up. My CM measurements are behind my eye chart. As in, my CM translate to -4.5 where as my eye chart is -3.75.

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Eye charts are not the most accurate way to measure diopter, as it is easier not to notice the blur on an eyechart. Being able to read a line on an eye chart is not the same as being able to see it without any blur. This explains the difference between your cm and chart measurements, It is easier to notice the edge of blur with cm measurements. If you want to reduce your noms, it is up to you to decide whether to do it when you can read a line confidently or when you can see the letters on the line without any blur.

I would suggest giving it some more time and paying attention to the amount of blur on the lines you can read. If you like a bit more challenge, you can reduce, but remember to work on the blur, and not just get used to it. You can also step back up for a while if you find you have over-estimated your improvement. Your reduced norms will wait for you. :smile:

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Thanks for the advice.
I don’t really think I am getting used to the blur. I try to make sure I can clearly make out the difference between the F and the P, the O and the C.
But as you said, I can just try and see if reducing make sense or just go back up.

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