Operation and Requirements of Drop Ball Test
The ball, which is 0.625 inches in diameter and weighs 0.56 ounces (16 grams), falls from 50 inches (127 centimeters) and hits the center of the lens. The geometrical center of the lens should be struck by the ball within a circle 5/8 inches in diameter. If the lens does not break, it is called a safety lens. There can't be anything that restricts the ball from falling. It cracks across the entire thickness, containing laminated layers (if any), and divides into two or more separate sections across the entire diameter.
The Disadvantages of Polycarbonate Lens
In this section, we will show you the disadvantages of polycarbonate glasses.
First, the polycarbonate lens is expensive than other regular lenses. It can cost up to double the price of regular eyeglasses.
Second, compared with high-index lenses, polycarbonate glasses have a lower abbe value, which is used to measure the dispersion of light for different eyeglasses lens materials. Polycarbonate lens rates lower mean they have the potential to cause slight chromatic aberrations in your peripheral vision.
Third, compared with Trivex lens, polycarbonate lens has bad durability since they are thinner and lighter.
What Are High-Index Lenses?
High index lenses are eyeglasses lenses that are designed to be thinner and lighter than regular lenses. High-index lenses have a high refractive index than their conventional counterparts. So, they are generally recommended for people who have significantly high refractive errors and strong prescriptions for nearsightedness, farsightedness or astigmatism.
High-index lenses correct all types of refractive errors. And they are also available as single vision lenses, or a reading prescription that corrects presbyopia, such as in a bifocal or progressive lens.
High-index lens has a higher refractive index and which is ranging from 1.53 to 1.74. A lens with an index of 1.74 could be up to 50 percent thinner than a regular plastic lens with an index of 1.50.
Large frame glasses
This year, glasses with large frames are popular, or glasses with wide edges are good-looking. The design inspiration of many series comes from the classic design. The rectangular frame shines brilliantly, but the angular line is softer. Many frames are made of synthetic fiber materials with excellent sculpture effect and wide application range, which has become mainstream.
How Do Prism Glasses Work?
After learning what prism glasses are, you should know how prism glasses work. So, in this section, we will show how prism glasses work.
People with binocular are struggling with seeing two images instead of a single image. The light they see falls in different places on their retinas, which causes distortion and doubling of what they are seeing.
Meanwhile, prism glasses are mostly used to deal with double vision, making it easier to maintain binocular vision, which is the ability to maintain focus on an object with both eyes. With the prism glasses, the light bent before it hits the retina. It is redirected so it falls correctly and the brain can interpret the message as getting in the usual manner, resulting in a single clear picture of seeing.
HINDAR blue light blocking glasses
With advanced equipment, system production, and strict management, they adopt German technology and PARUPU lens geometric structure owned by HINDAR OPTICE LAB, which can effectively block various kinds of blue light, ultraviolet light, and other different wavelengths, to protect the health of eyes. Since its inception, Hindar has enjoyed a lot of popularity, and while it has achieved some good results, it has not slowed down and is still striving to become the top brand in the industry.
Change the lens.
If you like your frames, but your prescription changes or the lenses are damaged, you can simply replace the lenses in the existing frames. Most optical shops will let you choose this method to reduce waste and save money. It is recommended that you take the frame to your local store and talk to the team. They will be able to assess the suitability of your eyeglasses and will be able to give you a quote based on your requirements.
