Can you adjust your glasses by yourself?
If your frames are not suitable, adjusting your glasses at home may be easier than you think. You can solve the most common problems in the frame by yourself, but sometimes taking your glasses to an optician is the best thing to do. Of course, if your problem is your lenses, that's something you can't usually fix at home.
Advantages of progressive multifocal lenses
The progressive multi-focal lens has a number of different focal points from top to bottom. There's a smooth transition between seeing far and seeing close. There is no clear dividing line in the middle, like the myopia glasses, quite beautiful, and it is not dangerous. Because the added value is continuously and slowly increased in the gradient area, the wearer can get a continuous clear vision from the far point to the near point through the progressive lenses with the appropriate head position. In line with physiological optics, They help a better adaptation. Since the lens degree changes little by little, there is no phenomenon like jumping. Because the degree of the lens is gradual, so the vision from far to near changes slowly increase, which will not produce the adjustment of the eye fluctuation. It is not easy to cause visual fatigue. Without a degree line, the appearance will be more beautiful. Clear vision can be obtained at all distances within the visual scope. A pair of glasses satisfies both close and middle distances.
Choose a good merchant.
The best option is to return the goods with a quality guarantee.High-quality pure titanium frame production cost is not less than 100 yuan, and online sales will be not less than 50%, so you have to be careful with prices less than 200 yuan. Because pure titanium frame material cost determines its price, the ultra-low price of pure titanium frame is definitely not real.
Types of Progressive Lenses
At the same time, there are different types of progressive lenses and they are standard PALs, short corridor PALs, computer PALs, and Reading PALs.
Standard PALs must fit your vision needs. They can be added to frames of your choice, but you need to ensure that the frames are the right width and height proportions to grant enough space for the gradient changes in the lens.
Short corridor PALs are made to fit into smaller frames so as to suit a wider range of eyewear styles.
Computer PALs are designed for computer users and other occupations that require strong intermediate and distance vision.
Reading PALs are designed for those who enjoy reading and they can opt for a pair of lenses with a larger close vision zone.
The design evolution of progressive lenses
Spherical and aspheric designs
The design of the front surface of the far-use area of the early progressive lens is similar to that of the ordinary spherical single vision lenses, so it is called a spherical progressive lens. Since 1974, the front surface of the far-use region of the lens is designed to be aspheric by designers, which not only reduces the peripheral aberration but makes the lens thinner, lighter, and less powerful.
Hard and soft design
For hard design, the channel is short, and the gradient is large. The near-use area position is high. The effective visual area of remote and near-use areas was larger. Peripheral astigmatism is relatively concentrated. Because surrounding astigmatism increases rapidly and the distribution is dense, the curve effect is more obvious. The gradient area is narrow. It is more difficult and takes longer for wearers to adapt.
Lenses with soft designs have slower gradients, longer gradients, and wider gradients. The angle of rotation of the eye from the far area to the near area is greater. It's easier to get used to. Compared with the hard design, the effective visual area of the far and near use areas is smaller, and the location of the near use area is lower.
Single, diverse, and individualized design
Initially, the progressive lenses used a single design, in which each basic curve was scaled equally and a luminosity combination was added within the range of its semi-finished lens blanks. The steepest base curve uses the same lens design as the flattest base curve. Lenses designers quickly realized that the overall performance of the lens could be improved by microcustomizing the lens design, leading to progressive lenses with multiple designs. This kind of design is called diverse design. By the mid-1990s, there was the emergence of individualized lens designs. In addition to using different gradients, these first individualized lens designs used steeper baseline curves with a slightly larger approach area to compensate for increased magnification and reduced field of view.
Symmetrical and asymmetric design
There is no difference between the left and right eyes in the symmetrical design of progressive lenses. As the eyes turn inward when they see near objects, the gradual gradient area gradually tilts to the nasal side from top to bottom, so the left/right progressive lenses should be rotated clockwise/counterclockwise respectively during processing. An asymptotic lens with left and right eye divisions is called an asymmetric design. The gradient is gradually and moderately inclined to the nasal side from top to bottom. The refractive force, astigmatism, and vertical prism of the two sides of the left and right gradient of the asymmetric design lenses are basically similar. At the same time, considering the characteristics of eye movement parameters in binocular vision, the peripheral aberrations of the corresponding positions of the left and right lenses were appropriately balanced to improve the visual effect of the wearer.
How to Choose Glasses for Round Faces?
Before proceeding with how to choose glasses for round faces, you need to what your face shape is. The round face shape has fuller cheeks which can give a more youthful appearance. The chin is rounder and the forehead widens at the top. In some cases, the jawline is softer than other face shapes. However, if you do not know what your face shape is, you can click here to check.
Are blue lenses good for driving?
Do not buy blue sunglasses, which cannot filter ultraviolet rays. In the choice of sunglasses, try to choose brown or gray. When driving a car, choose to wear sunglasses, and safety should come first. Wearing and viewing comfort is the most important indicator. It is worth reminding that wearing dark-colored sunglasses will create a very dark environment for the eyes, which will easily lead to pupil dilation, and long-term wearing will cause certain damage to the eyes.
