In the 1920 s America gave birth to a unique pop culture phenomenon flapper style.
Women have cut the fashionable short hair, wearing short loose skirt, are all the rage.
Due to the popularity of hair modelling, comb market collapse, run by the americans Sam Foster lady accessories company was faced with the threat of such.
At this time, he found a comb with injection molding technology can be used to make sunglasses.
So in 1929, made of celluloid sunglasses for the first time mass production, and sale in the big city, New Jersey beach.
Since then, sunglasses and went into the mass consumer groups.
Today, the sunglasses is not only a uv protection, also has become everybody street snap, concave shape when the must-have fashion item! ! !
Recommended reading: attention!
These people are not suitable for wearing sunglasses oh everybody when choosing and wearing sunglasses, but always appear all sorts of doubts.
For example: sunglasses why giddy?
How to choose the lens color?
Sunglasses tags on 1, 2, 3, 4 class is what mean?
First, we need to understand a word: transmission ratio.
Transmittance is also called the transmission coefficient, it is to point to the luminous flux through the lens and the ratio of the incident light flux, in a nutshell, is the visible light transmittance, or transmittance.
For example, if a certain kind of lenses transmission ratio is 40%, that is to say, only 40% of visible light can pass through the lens to the eye.
According to the visible light transmittance, the lens can be divided into 1 - from shallow to deep
Four categories: category: light color sunglasses.
Projected 43% ~ 80% than the most shallow color, shade and reduce flux at least, generally used as a fashion accessory mirror two categories: light color shading mirror;
Light transmittance 18% ~ 43% color, cloudy or cloudy;
Three categories: shading mirror;
Transmittance 8% ~ 18%.
Most sunglasses belong to this level, suitable for the sea, mountain climbing and other outdoor activities;
Four categories: special use sunglasses;
Transmittance 3% ~ 8% in skiing, the desert, is widely used, such as welding environment.
As requested, driving goggles transmittance is greater than 8%, so the class 4 sunglasses worn are not allowed to drive.
Some sunglasses will lead to the wearer unable to identify the traffic signals or difficult to identify, resulting in traffic accidents, because the traffic signal transmission than unqualified sunglasses.
Sunglasses should be no prescription, why put some sunglasses will be dizzy?
Colour: in the daily environment (
Such as indoor)
Long time wearing the lens color too deep,
Visible light transmission ratio is too low)
Sunglasses, causing visual fatigue, serious can appear the unwell symptom such as dizziness, nausea.
Sunglasses frames: its leg part wear tight, for example, oppression, temporal, cause dizziness, or glasses wearing the discomfort caused by stipule part, 3.
Lens processing problem: lenses is no luminosity (
In addition to the sunglasses)
, but if the process of plate type size is too big, crowded into the frame, lens in such a long twisted under the stress of optical index of the lens will be overweight.
Wearing this lens, light is dizzy, or affect vision.
In addition to the above situation, does not rule out some of the crowd to gradual dyeing lenses that discomfort.
What is the taboo wear sunglasses?
Glaucoma: when wearing sunglasses, reduction of visible light entering the eye, the pupil will naturally enlarge.
Pupil this change does not impact the healthy people but for glaucoma patients, but more increased intraocular aqueous humor circulation disorder, easy to induce acute glaucoma, jealous, eye pain, headache, nausea, vomiting, eyesight drops sharply and other symptoms.
So, glaucoma patients or suspected glaucoma, wearing sunglasses is not recommended.
Color blindness patients: not much affect achromatopsia person wearing sunglasses.
But some color blindness patients because only for lack of resolution of a few kinds of color, when wearing sunglasses are more cannot distinguish between colors.
And night blindness retinal and optic nerve inflammation etc. People also are not suitable for wearing sunglasses.
In addition, indoor do not wear sunglasses.
As sunglasses can make people's eyes in a relatively slightly dark light, then the pupil will loose big mechanically, vision and therefore affected.
In order to see better, naturally and watch the object, time is long, eye excessive regulation, easy to produce visual fatigue and photophobia and other symptoms.
related: brand sunglasses fashion sunglasses