All glasses sold by optical stores meet the applicable essential health and safety requirements provided by Regulation (EU) 2016/425 and the requirements set by the harmonized standards EN ISO 12312-1:2013 and EN ISO 12312-1/A1:2015. Sunglasses sold in optical stores are categorized as medical devices and must follow strict specifications. All sunglasses sold by optical stores come with an information note and a Declaration of Conformity as a reference to the above standards. This certifies that all glasses, regardless of price, are completely absorbent to ultraviolet radiation and its harmful effects on the eyes.
The material of the lenses can be crystal or organic. The crystal has the advantage in the fact that it scratches more difficult, but it is heavier and more fragile. Organic lenses, on the other hand, are much more impact resistant and very lightweight. This makes them ideal for large-format sunglasses.
The construction of the lenses must be such that it does not give distortions and irregularities of the image. Here’s the biggest difference with low-quality sunglasses.
The frame is made of durable and hypoallergenic materials. It accepts lens change and adjusts to the face.
Darkness & shade of lenses
Depending on their darkness, sunglasses are divided into four categories, with the 1st being the lightest, and the 4th the darkest. For sunny countries like Greece, the ideal darkness is in categories 2 and 3, while the 4th is considered suitable only for special occasions (mountaineering in a snowy landscape). For Greece, the ideal darkness is in categories 2 and 3, while 4 is considered suitable only for special cases (mountaineering in a snowy landscape).
The shade (brown, tinted, etc.) depends on the use and preference. Tinted colors modify the ambient colors less, being more neutral, while browns increase contrasts. Companies that specialize in good lenses (eg Maui Jim, Oakley, Vuarnet) “adjust” the color of their lenses to fit the requirements of the majority of prospective customers.
Polarised lenses
Polarised lenses further improve the comfort of sunglasses. Using the polarization of light, they “cut” many of the reflections on smooth surfaces, noticeably reducing glare. This has made them unsurpassed for use in driving and water sports.
Anti-reflective coatings
With the use of internal anti-reflective coatings, the very good glasses absorb even the rays that hit the back surface of the lens. They are highly recommended for small or flat frames, without bold sides.
Blue light absorption & retina protection
HEV (blue light) radiation is managed by some of the best lenses (eg MAUI JIM) and helps protect the retina.
When choosing your sunglasses, don’t forget to ask about the properties of their lenses, as they vary depending on the company and model.