Contact lenses may seem like a close concept, but in fact, the history of contact lenses goes back a long way. As early as 1508, the concept of the contact lens was first proposed, and the founder of this concept is known as the “future traveler” Leonardo Da Vinci. Like many of his ideas, the concept of contact lenses was well ahead of his time.
It was not until 1823 that the British astronomer Herschel developed a contact lenses design. In 1887, contact lenses made of glass were introduced for the first time. Contact lenses made of plastic were first introduced in 1939. Contact lenses made from soft materials such as gels were first introduced in 1971.
The design principle of contact lens is to make the object appear on the retina through the refraction of light through the lens, which to some extent replaces the zoom function of the eyeball, achieving the clear presentation of objects at different distances on our retina.
Contact lenses are made of a special material with a good light transmittance and a stable index of refraction. Lenses are made by a special process to correct various refractive errors of the eye.
Soft contact lenses
Soft contact lens according to the using period to classification, generally can be divided into: year, quarter, month, week. Threw the day and year cast type of contact lens use the longest time and the most preferential price. Every day and day type contact lenses in film, use rise more safe, and without the glasses to do special care, so more convenient and save time, but the price is more expensive.
Contact lens are divided into day, month and year behind, as the name implies, daily contact lenses after open is only take a day, also represents a day behind contact lens is disposable contact lenses, month behind the lens is to open a month can’t use, you must not use, because contact lenses also has expiration, another year is the same, can only take one year,.
in fact I think a year of contact lens is really a long time coming, generally do not take a year of contact lenses, I’m never taking enough for a year, in addition to the season, is change once a quarter, or once every three months to change.
How to choose contact lens?
The main thing about choosing a contact lens is to choose the one that works for you, such as the curvature of your cornea and how long you work. Contact lens have different base arcs, depending on the curvature of your own cornea. If you work for a long time, you can choose a super long one. Shikang or bausch &lomb pure vision are made of silicon hydrogel. They can be super long, but they are sold on a monthly basis and the price is too high. In addition, if it is the first wear to choose a better shape, so that they are more easy to wear, like bausch &lomb’s joy, easy to fit with the profusion series are standard thickness, more suitable for the first wear. Therefore, the choice of contact lenses to suit their own, not to brand based.
Let’s talk about contact lens wearing.
Contact lens and frame glasses are different, is to need to wear directly on the cornea, and the cornea needs to breathe, open to the cornea oxygen supply mainly from the atmosphere, a large wear contact lenses, it is easy to make it hypoxia.So in general, the continuous wear of contact lenses should not be too long, had better not more than eight hours, and must not wear contact lenses to sleep. If you wear it for more than 8 or even 12 hours a day, your cornea will be less sensitive to foreign objects and you will have eye problems.
Contact lens also need to be changed frequently, but it depends on how much you use them and the type of glasses you wear. If possible, it is best to use contact lenses that are frequently changed or discarded, and it is recommended to choose lenses with shorter cycles.
Especially for the daily throw, the service period is one day, after the period, it is easy to appear deformation, protein precipitation and other problems, not only wear uncomfortable, it is not good for our eyes.
If you wear poor quality or not consistent with the eyeball, will produce a certain degree of wear, cornea will be damaged, the eye will have discomfort, foreign body feeling, afraid of light tears and other manifestations.
If the damage is serious, when looking at the mirror found that there are white spots, it is likely to have become ulcer, it is best to see in time.
For the first time wear friends, it is recommended that the first day wear no more than 2 hours, the second to the fifth day no more than 4 hours, no more than 6 hours, a week later gradually to normal.
Each time the lens is removed, no matter how long it is worn, it should be cleaned and cared for. Remind everybody finally, should choose the glasses that suits him below the proposal of professional personnel, cannot oneself wear at will. Contact lenses are influenced by the surrounding environment and computer radiation metamorphism, although contact lenses in the relatively small changes in every day, but in the long run, the change is big.
And as more and long time contact lens use, precipitation in substances such as protein and bacteria on the surface of the lens is also more and more, although contact lenses can use nursing liquid to cleaning and soaking, but the sediment on the surface of the lens cannot be completely removed. It is conceivable that wear the expired contact lenses, eye easily infected, a series of symptoms, cause inflammation and other eye diseases within the eye.
The time that wears contact lens continuously should not exceed 8 hours, and it is to wear in the day, pick at night, do not wear sleep, if do not pay attention to clean nurse, wore for a long time, or late or early above a few trouble perhaps can seek a door, do not be not serious, should avoid to use misunderstanding, also should use an eye correctly at ordinary times. This is very important for science and health in the use of contact lens.
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thank you for reading.