Overcorrection

Overcorrection (full correction rounded to stronger 0.25 D step or more) is a correction you might sometimes get from a licensed optician.

One characteristic is that it usually gives you much better visual acuity than 20/20. It is not clearly defined at which ambient light level this is to be considered over-correction. However, it should be considered that opticians often prescribe lenses that correct you to at least 20/20 night vision on a 6m Snellen chart, therefore you may see better than 20/20 in bright sunlight without it being considered over-correction. If you can see better than 20/20 on a 6m Snellen chart at night with low levels of ambient light, it is probable that you are over-corrected, but it is possible that 20/20 correction gives you better than 20/20 vision while still being rounded towards the weak side of the 0.25 D step.