Reduce to 20/50 = reduce by 1-1.5 diopters?

An older and somehow forgotten @jakey’s recommendation.

What is going to be an equivalent in spherical or cylindrical diopters?

20/50 is suggested not because you should reduce to that number, but you should not reduce sooner than your next normalized reaches 20/50. But there is a reason it’s old recommendation, most people find better to reduce later and staying closer to 20/20.
And cyl reduction is totally different, it’s only for sph.


What is the difference between two? So I reduced and it looks I see good in my normalized. The next normalized gives me 20/50. Then, I wear 20/50 normalized. It is the same as reducing to 20/50 but not for the first time. Correct?

20/50 is an old thing. As with many things here, strategies continue to evolve. :wink:

The premise back then was, up to 20/50 indoors in less than ideal lighting is close enough. Small spaces less distance acuity needed. Once you get outside in better light, acuity improves appropriately.

I do need to update those references.


Why? It is useful for (even more so for very) high myopes, because it allows them to not swap lenses every 3-6 months.

Thank you for bringing this up. What’s the current recommendation then? (I’m at a loss.)

Reduce .25-.5 till 20/30-20/40 or slight 20/20.


what is the update ?