As the high development of technology, people’s life becomes more and more colorful and beautiful. In order to follow the trend of fashion, more and more people would like to make a pair of eyeglasses. There are different types of eyeglasses for customer chooses, you can choose them freely. People who wear eyeglasses with different areas are bifocal readers. Today, we mainly talk about bifocal eyeglasses for bifocal readers.
First, we have to know how to measure the bifocal eyeglasses in order to make a pair of suitable and proper eyeglasses for bifocal readers. The measurement for a pair of bifocal eyeglasses include far papillary, near pupillary and the high degree of lenses. The measurement of papillary is similar with the normal single vision eyeglasses, if you want to know how to measure the high degree of lenses, you can read the following passage in detail.
You have to choose a pair of eyeglasses frames for bifocal readers, then make adjustment to wear it on customer’s faces. The degree of anteversion is about 8 to 15. The distance between eyes and eyeglasses are 12 mm, and it must adjust your faces. The optometrist must sit face to face; their eyes must keep in the same level in order to make a pair of suitable and comfortable eyeglasses for eyewear. The customer looking the nose center of optometrist, then use the oil pen to drawn the horizontal line around the customer’s eye pupil center under the eyelids. Then put down the eyeglasses frames to measure the horizontal line to the inside of lenses of vertical distance on eyeglasses of right and left eye. The optometrist must ask the purpose of customer to make a pair of eyeglasses. If the customer uses the eyeglasses to see far, it is mean that the H is the top degree of eyeglasses. If the measurement of the high degree of lenses is different from the left and right eye, we have to take an eye exam to know the customer’s eyeglasses level. We have to carefully to make a pair of eyeglasses for bifocal readers.
Then, we have to know how to make a pair of bifocal eyeglasses to bifocal readers. We have to determine the level of processing on baseline to make a pair of bifocal eyeglasses. According to the height of the lenses to determine the vertical position of lenses and the vertex distance and near PD to locate the position of lenses. We have to know all of these factors carefully before we make a pair of bifocal eyeglasses. There are two kinds of bifocal eyeglasses for bifocal readers choose. One of them is Round Segment. This lens also gets its name from its shape. The reading power is in the bottom of the lens. This type of multifocal provides limited areas of near vision. The widest portion of the segment is either 22 or 24 mm.
Another kind of bifocal eyeglasses is Flat-Top Trifocal. A trifocal has three powers: for distance, near, and intermediate. Just like the flat-top bifocal, this lens segment is flat on top. The most common flat-top trifocals are: FT28 mm (7×28 mm) and FT 35 mm (8×35 mm). Again, the 28 and 35 indicate the widest portion of the segment, in millimeters, while the 7 and 8 represent the depth of the intermediate segment in millimeters.
Both of there bifocal eyeglasses are suit for bifocal readers. You can choose a pair of bifocal eyeglasses with my suggestions. It is good for you choose a pair of suitable and comfortable eyeglasses.