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In practice, an Abbe number change from 30 to 32 will not have a practically noticeable benefit, but a change from 30 to 47 could be beneficial for users with strong prescriptions that move their eyes and look "off-axis" of the optical center of the lens.[citation needed] Some users do not sense color fringing directly but will just describe "off-axis blurriness".[citation needed] Abbe values even as high as that of ( Vd ≤ 45 ) produce chromatic aberrations which can be perceptible to a user in lenses larger than 40 mm in diameter and especially in strengths that are in excess of ±4 D. At ±8 D even glass ( Vd ≤ 58 ) produces chromatic aberration that can be noticed by a user.[citation needed] Chromatic aberration is independent of the lens being of spherical, aspheric, or atoric design.