Roger Bacon
One of the first people credited with inventing glasses was an English friar in the 13th century, Roger Bacon. In his Opus Majus (c. 1266), he outlined the scientific principles of the use of corrective lenses. Some writers believed that monks or friars possessed secret knowledge about glasses, which they later disseminated around the world. Most famously, William Molyneux wrote in his Dioptrica Nova (1692). Unfortunately, there is no evidence that Bacon ever applied his theoretical knowledge of perspective (optics).
Why do blue light glasses turn yellow?
The glasses are used for a long time. Blue lenses are usually light yellow. If the yellow is too deep, the resin lenses will oxidize and become yellow due to the long-wearing time. The lenses need to be replaced in time. Yellowing of the lens is related to the excessive secretion of facial grease, which leads to yellowing of the lens. The most direct way is to replace the lens glass.
Orthokeratology lenses are used for myopia control.
The effect of the orthokeratology lens in controlling the increase of myopia in teenagers has been unanimously affirmed by the ophthalmology industry at home and abroad. In February 2006, an authoritative ophthalmological journal published a review of the retarding effect of rigidity breathable orthokeratology lens on the progression of myopia in children. This paper reviews the literature on orthokeratology and myopia in the past 30 years and points out that rigidity breathable orthokeratology can prevent or alleviate the progress of myopia, the mechanism of which is that rigid breathable contact lens can inhibit the progress of myopia by providing clearer retinal image quality. Medium and high concentration of atropine will affect students' near-use vision, while low concentration of atropine has not been used clinically in China, so orthokeratology lens has become one of the known myopia control methods with the best statistical effect. In three to five-year case studies, orthokeratology lenses alleviate a 40 to 60 percent increase in myopia compared with wearing a frame lens or a soft contact lens. Other studies have found that 65 to 70 percent of orthokeratology lens wearers show little or no axial length increase.
Types of Bifocal Lenses
Flat top: It is a kind of common bifocal lenses. The lower part of the lens is present in the shape of a half-moon or the letter D on its side. The upper part and the lower part of the lens can be clearly distinguished from each other. The patient using such a bifocal lens has the choice of choosing the length of the lower segment which is either 25 mm or 28 mm.
Round seg: the second type of bifocal lens we want to mention is the round seg. The segment is either 22 or 24 mm in length and it provides more are to adjust between the two different types of vision easily. This type is very rarely used nowadays.
Blended: this type of bifocal lens has the lower part of the lens in a round shape and the edges of the lens are blended with the upper lens making the lens appear as one.
What is blue light?
To prevent blue light, we must first understand what blue light is. The visible light with a wavelength range of 400-500 nanometers is called blue light. The light sources used in daily LED lighting and display products, including mobile phones, flat panels, and TVs, are mostly LED light sources excited by blue light. However, not all blue light is harmful to the human body. The human eye has an extremely low tolerance to blue light radiation in the 400-440 nanometer range. When the light intensity enters this threshold, photochemical damage is likely to occur. However, blue light radiation in the range of 459-490 nanometers is essential for regulating the human body's circadian rhythm and can affect the secretion of human melatonin, which in turn has an impact on the body's biological clock, alertness, and mood.
Scientifically effective anti-blue light lenses must not only block harmful blue light but also cannot filter beneficial blue light. Most of the ineffective anti-blue light products on the market currently have two types of problems. One is that there is almost no protective effect on the blue light in the vulnerable zone of the human eye. The other is excessive protection, shielding the blue light spectrum in the beneficial band so that the blue light that is beneficial for physiological adjustment cannot enter the human eye. At the same time, the color of the lens is yellow, which is prone to color shift, aggravating visual fatigue, and even inducing the risk of myopia.
Pair clear glasses with natural makeup.
Clear glasses and light makeup can make the focus of others in the glasses, so it will not appear abrupt. With a plain color coat, there is no sense of violation, and it is playful. A frame without lenses can be an accessory to give you a different feel.
Clear glasses are in fashion.
Unlike those who used to wear plain glasses for the sake of a polite way, it is important for young men and women to wear glasses today to show their individuality, personality, and non-mainstream style. The clear eyeglass frame is classic, as the black frame. But relatively speaking, a clear white eyeglass frame has certain requirements to face shape, skin color, hairstyle. However, if you wear them properly and have enough confidence, those clear frames can be very stylish.
