A colour vision disorder of genetic or acquired origin, colour blindness affects men more than women. It is characterised by the subject's difficulty in distinguishing between the colour red and green.
To overcome this problem, glasses are made with specific characteristics. There is a whole range on the market, available from opticians or pharmacists.
The characteristics of colour blind glasses
Optical lenses for colour blind people generally resemble the various lenses commonly used. The difference here is that there are other criteria that are taken into account in the design. A colour-blind person is first and foremost an individual like everyone else. The glasses he wears have the same configuration as those of others. They therefore have :
- Two branches;
- Two sleeves;
- A bridge;
- Two hinges;
- Two booklets;
- Two tenons
- Two circles ;
- Two glasses.
The specificity lies in the quality of the lenses. It is not a question of correcting a visual disorder such as myopia, hyperopia or presbyopia, but of allowing a shade of colour. The manufacture generally takes into account the type of colour blindness and the stage of development of the anomaly. In order to understand this, it is necessary to refer to the way in which these binoculars work.
How colour-blind glasses work
People with colour blindness as mentioned earlier often confuse the colours red and green. Depending on the type of colour blindness, some people only perceive shades of grey. All these factors explain the complexity of developing corrective lenses. In 2010, thanks to the paint manufacturer Valspar and the start-up Enchroma, glasses were developed. Before looking at how these glasses work, it is important to know the normal physiology of colour vision.
Normal colour vision
Colour perception, or chromatopsia, is a complex physiological process that combines stimuli that cause sensations. It takes place within the organ of sight, the eye. The eye is made up of the following parts
- The three membranes in the periphery: the sclera, the choroid and the retina;
- The three transparent media in the centre: the aqueous humour, the lens and the vitreous body.
The part most involved in chromatopsia is the retina. In its structure, it has two categories of cells called photoreceptors namely :
- The cone photoreceptors: they are located in the centre of the retina and allow colour vision;
- Rod photoreceptors: these are peripheral and allow night vision.
The cones consist of a main pigment called iodopsin of which there are three types depending on the wavelength of the light received. We distinguish between :
- The green cone for iodopsin S ;
- The red cone for iodopsin L;
- The blue cone for iodopsin S.
Chromatopsia involves all three types in the retina. In the case of dyschromatopsia, one of the cones is defective. Three types of colour blindness can be distinguished:
- Protanopia: this concerns the L cone. The subject lacks L iodopsin, which means that the red is there, but deficient;
- Deuteranopia: this involves the M cone. There is an absence of M iodopsin, which indicates a deficiency of green. This is the most frequent form of colour blindness.
- Tritanopia: the photoreceptor involved here is the S-cone. The S iodopsin is missing, which means a blue deficiency. This form of dyschromatopsia is extremely rare.
How do corrective glasses work?
Colour-blind binoculars separate the different types of colours, enabling the subjects concerned to distinguish yellow, blue, pink, etc. They proceed by selective filtration of the wavelengths perceived by the eye precisely at the point where they merge or overlap. They then promote an amplification of the chromatic signal sent to the integration centre (the brain).
However, the primary colours need to be blocked, so the filter will make some precision cuts in the spectrum to induce an interruption of them. The lenses allow the appearance of certain colours by increasing the contrast between the red and green colour signals. The symptoms of dyschromatopsia are then reduced. The subjects will then be able to better apprehend nature under these different aspects.
Possible side effects of these glasses
The use of specific glasses to correct colour blindness sometimes presents undesirable effects which are corrected with habit. In fact, the colour-blind person who has been living with the disorder since childhood or for a long time adapts by developing certain reflexes. He has his own reference point and sees the world in his own way. This attitude allows him to integrate optimally into society.
Thus, the adoption of a miracle solution will cause a total upheaval at first. From now on, he sees and distinguishes things clearly on the real and authentic aspects like everyone else. He has to review his bearings and change his reflexes to better accommodate. Such a condition can lead to disorientation and disturbances in his physiology. It is essential to seek medical advice before purchasing these binoculars to avoid a dead end.
Where can I get colour-blind glasses?
To buy corrective lenses for colour blindness, you should ideally have a doctor's prescription and go to a specialist. This is the optician, but you can also go to a pharmacist. Alternatively, you can opt for a faster option: the Internet. There are now companies that manufacture corrective lenses for colour blind people and have online platforms.
Go to a search engine and start your query. Within a short time, you will have many solutions ready to meet your expectations. Just choose one and explore the company's website. You have the option of ordering directly online and having your order delivered to your home, or you can contact them for a physical appointment.
Very often, the professionals submit you to the diagnostic text before and after wearing the glasses. This is to check the presence of the disorder first and to assess the correction second.
The different brands available on the market
There are several companies offering glasses to correct colour vision deficiency. The most common are :
- Enchroma : Enchroma is the leading brand in the market and is revolutionising the treatment of colour blindness with a range of patented, state-of-the-art products. The company offers eyewear that combines recent neuroscience innovations in colour perception. These are sold online and around the world at retailers. The start-up received the Tibbetts Award in 2016 for its achievements;
- Pilestones : An American brand like Enchroma, it uses technology to enable colour blind people to see colours as they really are. The company offers a wide range of lenses and you can take the screening test online;
- Kolorblind: The company not only offers glasses for colour blind people, but also gives them the possibility to get in touch with an optician on its platform. It corrects the two most common forms of colour blindness: protanopia and deuteranopia.