Why do some sunglasses wear giddy meeting?
Many people find that some sunglasses make them dizzy.Don't sunglasses have any power?How can giddy?
1. Lenses color: Wearing sunglasses with excessively dark lenses (too low visible light transmission ratio) in daily environment (such as indoor) for a long time will cause visual fatigue, and serious symptoms such as dizziness and nausea will occur.
2. The frame of sunglasses: for example, the legs of the glasses are too tight, which presses on the temple, leading to dizziness, or it is caused by the discomfort of wearing the cobra of the glasses.
3. Lenses processing problem: sunglasses lenses are not luminosity (except for myopic sunglasses), but if the size of the lens is too large during processing, forced into the frame, the lens under such long-term distortion stress, the optical index of the lens will exceed the standard.Wear such lenses, light dizziness, heavy vision.
In addition to the above circumstances, it does not rule out that some people are not comfortable with the lenses of progressive dyed sunglasses.
Are the lenses of sunglasses good or bad?
Each lens material has its own advantages and can not be simply "good or bad" to distinguish.
For example, glass lenses, although wear-resistant and better optical properties, but because the lens is heavy, so the use of gradually reduced.
Resin lenses (such as CR39 materials) are easy to color, light and impact resistant, making them one of the mainstream materials for fashion sunglasses.However, the resin lens is prone to edge collapse in the process of edge cutting, and will still be broken in the face of huge impact force.
At this point, PC lens is better than resin lens, it is characterized by light, good coloring performance, stronger impact resistance, the disadvantage is low wear resistance.
TAC sunglasses lenses are widely used in China.TAC (TriacetylCellulose) is one of the polymer materials with good light transmittance. As a solar lens, TAC has the characteristics of acid and alkali resistance, light and thin texture and high cost performance. However, poor wear resistance has become the weakness of TAC lens.
Nylon sun lens is used in the production of sports sunglasses, it has high elasticity and excellent optical quality, strong impact resistance, with professional protection function;But production costs are high.
Are there any taboos when wearing sunglasses?
The following people should pay extra attention when
using sunglasses:
Glaucoma patients: When wearing sunglasses, the visible
light into the eyes decreases, the pupil will naturally dilate.This change in
the pupil has no effect on healthy people but for glaucoma patients, it has
increased the obstruction of aqueous humor circulation in the eye, and is easy
to induce acute glaucoma attacks, such as red eyes, eye pain, headache, nausea,
vomiting, sharp decline in vision and other symptoms.
Therefore, sunglasses are not recommended for people with
or suspected glaucoma.
Color blind patients: full color blind people wearing
sunglasses did not have a big impact.But some people with color blindness lack
the ability to distinguish only a few colors, and when they wear sunglasses,
they can't distinguish colors even more.
Still have the crowd such as neuro retinopathy of night
blindness, optic also does not suit to wear sunglass.
Do not wear sunglasses indoors
Because sunglasses put your eyes in relatively dim light,
your pupils will subconsciously dilate and your vision will be affected.In
order to see more clearly, naturally hard to watch the object, for a long time,
the eye adjustment is excessive, easy to produce visual fatigue and photophobia
and other symptoms.
Director wong kar-wai is a typical example, he said:
"the sunglasses can be said to be the film of a price for so many years, I
usually write the screenplay by day and night shooting, eyes have become
accustomed to the darkness, if took off her dark glasses, you will not see my
eyes --, see will be tears, because my eyes are too sensitive to
light."That's why he's always wearing sunglasses.
