Unless you have a vision problem, or a deformity of the pupil and iris, your only knowledge of prosthetic eye contacts is most likely the ones used as parts of costumes in movies and at Halloween. Prosthetic eye contacts utilize a special kind of technology to paint on contact lenses online in various degrees of opacity. For some vision problems, this is a very unobtrusive way to correct vision problems.
Decades ago, the only option you had to correct certain vision problems was to don an eye patch to force the weaker eye to work. Unfortunately, the treatment works best if the problem is addressed when young and wandering around in an eye patch makes being called “four-eyes” on the playground seem a compliment. With the development of prosthetic eye contacts, a less stressful form of treatment is allowed. One of the contacts has an enlarged pupil painted on it with an opaque paint, blocking that eye’s vision and forcing the other to work. The companion prosthetic has a matching enlarged pupil painted on it to make the eyes look normal and matched, but that paint is not opaque.
Prosthetic eye contacts are also used to mask irregularities in the iris and pupil. Some people have pupils that run through the iris like a pie shape. Some have pupils that are vertical lines instead of circular. A prosthetic set that is painted with matching pupil diameters can conceal this irregularity and normalize a person’s appearance. While many people are born with this irregularity, more acquire it through trauma to the head. Recovering from physical trauma is hard enough without also dealing with a highly visible deformity.
Another condition that prosthetic eye contacts can help is a natural irregularity, or mismatching, between the eyes. David Bowie is perhaps the most well-known owner of a pair of differently coloured eyes. Not everyone thinks that having eyes like this is a great thing and it can be damaging to one’s self esteem. It can also come with an increase photosensitivity in one or both eyes. By using contacts that even out shape and colour, the person has a more normal appearance. For those that are sensitive to light, a slightly opaque treatment is used on the lens to make them a kind on subtle sun shade.
Prosthetic eye contacts were developed to address ocular irregularities, not to turn people into zombies and vampires for the evening. That it is becoming more common for people to own coloured contacts is helping those with vision issues as the price of the eye contacts is dropping and having unusual eyes is becoming more socially acceptable.