There is no cure for<unk>  deficiencies. The American Optometric Association reports that a contact lens on one eye can increase the ability to differentiate between<unk> s, though nothing can cause a person to actually perceive the deficient<unk> . Lenses Optometrists can supply<unk> ed spectacle lenses or a single red-tint contact lens to wear on the non-dominant eye, but although this may improve discrimination of some<unk> s, it can make other<unk> s more difficult to distinguish. A 1981 review of various studies to evaluate the effect of the X-chrom contact lens concluded that, while the lens may allow the wearer to achieve a better score on certain<unk>  vision tests, it did not correct<unk>  vision in the natural environment. A case history using the X-Chrom lens for a rod monochromat is reported and an X-Chrom manual is online. Lenses that filter certain wavelengths of light can allow people with a cone anomaly, but not dichromacy, to see better separation of<unk> s, especially those with classic "red/green"<unk> . They work by absorbing wavelengths that strongly stimulate both red and green cones in a deuter- or protanomalous person, improving the distinction between the two cones' signals. As of 2012, eyeglasses that absorb<unk>  wavelengths are available commercially. Apps Many mobile and computer applications have been developed to help<unk>  blind individual to better differentiate between<unk> s. Some applications launch a simulation of<unk>  to allow people with typical vision to understand how people with<unk>  see the world, which can improve inclusive design for both groups. This is achieved using an LMS<unk>  space. After analyzing what<unk> s are confusing, daltonization algorithms can be used to create a<unk>  filter for people with<unk>  to notice some<unk>  differences more easily.
Color blindness
Flash blindness
Tunnel vision
Myopia
Cortical blindness
Amblyopia
Red eye 
Retinopathy