Abbe Value of the human eye

[Jane]

Can someone please direct me to a discussion or information regarding the Abbe Value of the human eye. thanks jane

[optispares]

Abbe Value
The measure of a material’s characteristic of breaking light into its component colors, abbe value has been a constant concern with high index lens materials. When white light (e.g., sunlight) is refracted, it breaks down into a rainbow. This is referred to as “dispersion� or “chromatic� aberration. Since the colors focus at different points relative to the retina, the wearer may experience nonspecific blur and color fringes around viewed objects. For example, the wearer may complain that objects appear to have colored borders. The higher the Abbe value number, the better the lens controls this problem. Fortunately the human eye has an internal Abbe value of about 45, so in practicality, we need only to be concerned with materials exhibiting substantially lower values. There is some evidence that high myopes are more sensitive to Abbe value than hyperopes, and of course they are the largest target market for these materials in the United States. Consider Abbe value problems if the finished glasses are “on the mark� in all respects (Rx, base curve, centration, tilt), but the wearer still complains of visual discomfort.

[shanbaum]

optispares said:
Fortunately the human eye has an internal Abbe value of about 45, so in practicality, we need only to be concerned with materials exhibiting substantially lower values.

Odd notion. Chromatic abberation through a lens system (including the combination of a spectacle lens in front of an eye) would accumulate, would it not?

[caheo883]

The Abbe number,] VD, of a material is defined as

where nD, nF and nC are the refractive indices of the material at the wavelengths of the Fraunhofer D-, F- and C- spectral lines (589.3 nm, 486.1 nm and 656.3 nm respectively).
Abbe numbers are used to classify glass and other optical materials in terms of their chromaticity. For example, the higher dispersion flint glasses have V < 55 whereas the lower dispersion crown glasses have larger Abbe numbers. Values of V range from below 25 for very dense flint glasses, around 34 for polycarbonate plastics, up to 65 for common crown glasses, and 75 to 85 for some fluorite and phosphate crown glasses.
More in wiki: https://en.wikipedia.org/wiki/Abbe_number

[Barry Santini]

The main reason the eye has *longitudonal* (axial) chromatic aberration is that the refracting elements, the lens and cornea, are so similar in index of refrraction. The eye has approx 2D of axial chromatic aberration
B

[AngeHamm]

Zombie thread!