What does Plano mean on an eye prescription?

What does Plano mean on an eye prescription?
OS means the left eye, plano means that eye needs zero correction - there is no short-sight, no long-sight, no astigmatism, the prescription to correct the focussing error for the left eye is 0/0… “plano” (flat plane glass, no convex curve, no concave curve, planar, plano).

Reference:
What does Plano mean in the OS eye? - Quora
Feb 7, 2018

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