What glasses are suitable for a person with a round face?
Pay attention to choosing the right shape. The too-small glasses for a round face will make it look bigger. You should choose some large-frame glasses or the irregular glasses that have become so popular in recent years. You can choose long or square frames, and angular long and square frames will increase the line of your face, making your face look more three-dimensional. You had better match the thin glasses that takes curve slightly to reconcile the whole feeling. Just make sure that the size of the glasses is proportional to the size of the face.
What Is Photophobia?
There are a lot of reasons causing our eyes discomforts, such as moving between indoors and outdoors on bright sunny days, staring at computer screens all day, driving at night, or watching TV. If the discomfort worsens over time with accompanying symptoms such as intense pain, excessive squinting, excessive tearing or burning sensations, it may become an eye condition called photophobia or light sensitivity.
One of the symptoms of photophobia is intolerance of light. To some degree, most of us are sensitive to bright or fluorescent lights, but those suffering from photophobia may experience a range of symptoms - from minor or mild irritation to serious debilitating reactions. The symptoms can include dizziness, headaches, migraines, server eye pain, excessive blinking, blurriness, and eye inflammation.
So, they are a few ways to combat photophobia.
The refractive index of lens
Refraction law is discovered by Dutch mathematician Snell.It is the law that determines the direction of refracted light in the phenomenon of light refraction. When the light from the first medium (refractive index N1) into the second medium (refractive index N2), part of the light from the first medium into the second medium at the smooth interface will be refracted. The index of refraction is the ratio of the speed at which light travels in a vacuum to the speed at which light travels in the medium. For glasses lenses, the higher the refractive index, the thinner the lens, that is, the lens with the same center thickness and the same degree, the lens with the higher refractive index has thinner edges than the lens with the lower refractive index of the same material.
What's wrong with your not clear phone's screen, low brightness, or even black screen when wearing polarized sunglasses?
There is a polarizing plate in the display structure of the mobile phones, which comes from the photoelectric modulation effect of the display screen. There is a polarized light absorption axis in the polarizing plate, which is consistent with the polarized light absorption principle of the polarized sunglasses. If the polarization absorption axes of the two are parallel, the screen can be seen. When they are perpendicular to each other, the light emitted by the screen will be absorbed by the sunglasses, and the light cannot reach the eyes, leading to the phenomenon of the black screen or low brightness. There may be differences in the direction of the absorption axis of the polarizer. So after wearing the polarized lenses, when you see low brightness or black screen, there are two different situations: landscape screen and portrait screen.
Why should you clean the eyeglass case?
Although the eyeglasses case is used less, it can not be separated from the glasses. If it is not cleaned for a long time, it will affect appearance and carry a lot of bacteria.
The categories of rimless glasses
Rimless glasses can be divided into metal rimless glasses and plastic rimless glasses according to the material. According to the metal category, they can be divided into nickel-copper alloy, memory titanium alloy rimless frames.
According to the elastic order of the frame, the softest and elastic kind is the plastic rimless glasses. The benefits are the lightest weight and the lowest price. The disadvantages are the short service life, faded look after the sun, and single appearance, which are suitable for children or teenagers in the stage of corrective treatment. The second elasticity is the memory titanium alloy rimless frame. They use aviation metal titanium as the raw material, suitable for people with sensitive skin, and have lighter quality, better durability, more styles.
The Optical Center of A Lens
When wearing glasses, try to look through the optical center of the lens. This needs the cooperation of the neck, you can slightly lower the head when looking at the computer, to adjust the line of sight. The Center of optical glasses is divided into two kinds: 1 mm up myopic lens center is the most proper, of course, more than 2-3. And the most important thing is that the lens pupil high (about the two-lens optical center of the high and low) must be proper (that is, the right of the lens optical center is 1 mm, the left must be 1 mm. 2-3 mm is the same, what is the height of the pupil on the right side must be the same on the left side. The optical center of the presbyopic lens is 1 mm, the most proper.