A measure of the tendency of an eyeglass lens material to cause chromatic aberration, which is an optical distortion that causes colored halos or fringes around lights or blurred vision, especially when looking through the periphery of the lens. The lower the Abbe number, the more likely chromatic aberration will be noticeabl

A device that can identify common and more obscure vision errors by measuring the way light waves travel through the eye's optical system.

Removal. In vision, ablation refers to the surgical removal of eye tissue to correct a refractive error such as myopia. For example, in laser procedures such as LASIK and PRK, the excimer laser ablates, or removes, tissue from the cornea.

A lack of certain receptors in your retinas. Your vision won’t be sharp, and you could be nearly or completely colorblind. It’s an inherited condition.