Unbranded sunglasses can cost considerably less than the originals, or branded ones. If we only take the cost factor into consideration, these glasses may look like a good deal, but the cheap can be very expensive, especially for your health.
These glasses are sold without any kind of prescription or any quality guarantee. Apparently these glasses serve their purpose, but their long-term use can lead to the development of eye melanomas, inflammation, retinal degeneration or cataracts.
If you have ever stayed up late at night, you may have noticed a peculiar fact about your eyes. The human eye tends to compensate for the lack of light, so our pupils increase when we are in a dark environment. It is important to understand that our eyes are made up of different parts, the outer part we call cornea, the iris that gives colour to our eyes, but also serves to control the amount of light that enters our eyes through the pupil.
Cameras work in a similar way. To capture an image, we have to control the amount of light entering through the diaphragm of the lens, which we can open more or less depending on the conditions of lower or higher brightness, which means, that just as the quality of a photograph depends on the amount of light captured, our vision depends on the capacity that the iris has to control the amount of light entering through our pupil. If during the day the size of our pupil is smaller because the environment, in general, is more illuminated, the opposite is also valid for the night period. There is less light, so our pupil becomes larger in order to enter as much light as possible.
Just note the following detail, our pupils may also vary in size in response to emotional stimuli. If we feel angry or afraid, for example, our pupils change their size. If they are under the effect of medication or drugs, this phenomenon is also observed.
Considering the above, when we wear sunglasses, the pupil naturally dilates, as it assumes it is in an environment with less brightness. If the glasses do not have an indicated protection against UV rays, in the long run this will cause cataracts or even melanoma. This is why the use of unmarked sunglasses can be more dangerous and harmful than wearing nothing. Some problems do not even need prolonged exposure to begin to manifest. For example, it only takes 6 hours of uninterrupted exposure to sunlight for the cornea to show signs of inflammation, such as redness or dryness.
It is never too much to remember, only wear glasses with CE certification and with UV400 or UV100% filters, for your eye health.