The types of contact lenses depend on the way they are made, and the different methods and materials used to make them. If you want to become a qualified contact lens distributor, then you can continue to check out this article.
Q1.What are the manufacturing methods of contact lenses?
The manufacturing methods of contact lenses are broadly classified into the following 3 types:
Lathe cutting method
Cutting method, using a lathe to polish rod-shaped and plate-shaped materials, etc.
Casting and molding method
The raw material is injected into the model made of special plastic by heat and ultraviolet coagulation method.
Centrifugal casting method
The Freshlady method is a method of solidification in which the raw material is injected into a concave model and rotated while solidifying.
Q2.What kind of material are contact lenses made of?
Contact lenses are made of special plastic. Hard contact lens materials have the property of passing a large number of oxygen elements, and soft contact lenses have the property of containing water and becoming soft. In addition, the plastic used as the material for contact lenses is made by combining various components with different properties. In addition to the ingredients that allow oxygen to pass through and those that contain water, they also combine ingredients that make them strong, ingredients that make it difficult for dirt to adhere, ingredients that make them soft, and so on, to create contact lens materials with a variety of characteristics.
Q3.What types of contact lenses are there?
By material: Soft contact lenses are made of soft materials and hard contact lenses are made of hard materials.
Classification according to usage period: Soft contact lenses can be divided into traditional soft contact lenses that last longer, and soft contact lenses that are replaced once a day and regularly (1-week replacement, 2 weeks replacement, 1-month replacement, 3 months replacement, etc.). Hard contact lenses are all traditional.
According to functional classification: they can be classified as lenses for nearsightedness, for farsightedness, for astigmatism (toric lenses), and for both near and far use.
Q4.How long does it take to make contact lenses at the factory?
Depending on the type of contact lens, the production time varies.
The time required to make contact lenses that are replaced once a day and once every 2 weeks using molds: It takes from ten minutes to several hours to make one contact lens.
In addition, the process of using molds can produce many lenses at the same time.
Hard contact lenses made from plastic blocks, etc.: It sometimes takes several days to make 1 contact lens.
Q5.What are silicone hydrogel contact lenses?
Silicone hydrogel contact lenses are soft contact lenses made of a material that contains silicon. Silicon is extremely permeable to oxygen. When these contact lenses are worn, sufficient oxygen can pass through the lens and reach the cornea. Other advantages of silicone hydrogel contact lenses (over traditional soft contact lenses) include reduced lens dryness, prevention of protein deposits, reduced eye infections, more flexible material that is easier to handle, and greatly reduced complications with long-term wear.
Q6.What is the difference between hard and soft contact lenses?
Soft contact lenses are made of hydrophilic polymers. They range from 38% to 71% water content and are soft and comfortable. Hard contact lenses are not made of hydrophilic polymers and therefore do not contain water. They have great benefits for eye health but are initially less comfortable than soft contact lenses.
Q7.Why do soft contact lenses stay on top of the black eye?
This is because the curvature of the black eye is less than the curvature of the white eye. Soft contact lenses are designed to bend slightly more than the curvature of the black eyeball and slightly less than the curvature of the white eyeball. When the soft contact lens is placed on the black eye, the peripheral portion of the lens is on the white eye.
Since the curvature of the white eyeball is greater than the curvature of the lens, the portion of the lens exposed to the white eyeball is slightly stretched and stuck to the eyeball.
Since the elongated lens has to return to its original shape, a force is generated in the direction of the lens contraction. By this force, the lens becomes slightly constricted to the eye and remains stable.
In this state, if the lens deviates to the white eye with a large curvature, the lens is further stretched and the force of the lens contraction to return to its original shape becomes greater. By the force generated when the lens is stretched and has to contract to return to its original shape, the lens returns to the original black eye.
Q8.What is the difference between disposable contact lenses and regular replacement contact lenses?
Disposable contact lenses can be worn only once and then discarded, while scheduled replacement contact lenses are worn for some time and then replaced on a regular cycle.