Contact lenses are very practical for people who don’t want to wear glasses. But how are they actually manufactured and what standards must be observed? This question is answered in this article and everything you need to know about it is highlighted.
Material selection
Careful selection of the right material is crucial during manufacturing. The choice depends on various factors that influence the quality, comfort and tolerability of the lenses.
- Oxygen permeability: Oxygen supply to the eye is essential to ensure the health of vision. Modern contact lens materials are designed to allow sufficient oxygen permeability to the cornea to supply the required oxygen.
- Wetting ability: Comfortable wearing depends on the ability to retain moisture and adequately wet the surface of the eye. Materials with high wettability reduce the feeling of dryness and irritation.
Types of contact lenses
Every person has individual needs and other requirements, which are crucial when choosing lenses. A distinction must be made between these types of contact lenses:
- Daily lenses: These visual aids are intended for single use. In contrast to hard lenses, they cover the large area of the cornea and adapt better. However, this can reduce oxygen supply and therefore limit the recommended wearing time. The delicate surface is more susceptible to deposits and damage. Therefore, they should be cleaned before and after each use.
- Monthly lenses: Monthly lenses are worn for a period of 30 days. They are even available with high diopter values for those with severe vision problems. In addition to nearsightedness or farsightedness, toric shaped monthly lenses can correct astigmatism.
- Toric lenses for astigmatism: Toric contact lenses are used to correct the visual defect of astigmatism, which often occurs along with nearsightedness or farsightedness. Depending on the severity of the astigmatism, appropriate toric contact lenses are recommended for adjustment.
- Progressive contact lenses: Multifocal contact lenses, also known as Progressive contact lenses are called, enable existing visual impairments and presbyopia to be effectively corrected. Several diopter values are incorporated into its material. In this way, they can improve existing ametropia and age-related farsightedness (presbyopia) at the same time. By dividing it into different visual zones, you can see clearly in all situations and distances.
What factors should be taken into account during production?
Precise contact lens manufacturing requires consideration of several key factors. From the shape or Photolithography to the final surface polishing – every step influences the quality and comfort of the lenses.
- Making molds: This is where exact molds are created that reflect the desired design of the contact lens. This can be done using precision machining or photolithography.
- Casting or Cutting: The selected contact lens material is placed into the mold. This happens through casting or cutting.
- Curing or polymerization: When a polymerizable material is used, it can be cured using heat, light, or chemical reactions to form the contact lens.
- Surface processing: The lens is polished to obtain a smooth surface that increases wearing comfort.
Quality control of contact lenses
The quality standards for contact lenses are very high because they are a medical aid that is used directly on the eye. An essential step in this process is the thorough quality control of each individual lens. This critical review aims to identify irregularities and other quality deficiencies.
Possible errors or deviations are detected using high-precision optical instruments and modern technologies. Each lens is checked for correct shape, uniform thickness, smooth surface and optical clarity. The purpose of the check is to ensure that the contact lenses not only provide the necessary vision correction, but also are comfortable to wear. Only the lenses that withstand these strict tests and meet all quality criteria ultimately make it into your hands in the eyes of consumption.
Cleaning and sterilization
After production, the contact lenses are cleaned. This process is of utmost importance so that the lenses are free from any contaminants. This thorough cleaning is necessary to remove particles, residues or microorganisms in order not to endanger eye health.
They then undergo a special sterilization process to eliminate any remaining contamination. This careful cleaning and sterilization process is crucial to ensure that the contact lenses are hygienic.
Packaging of contact lenses
Contact lens packaging ensures that the lenses remain in perfect condition. After going through the manufacturing and quality control process, they are packaged in special, sterile containers.
These cases are designed to protect the contact lenses from external influences such as dust and moisture. Packaging goes beyond just the physical casing – it ensures that the lenses reach the user in the best possible condition. Many consumers use the lens cases several times before throwing them away. It is therefore important that they are robust, sterile and securely closed.
Conclusion
Overall, the production and quality assurance of contact lenses is a combination of science, technology and the finest precision work. This process ensures that they not only provide vision correction, but also provide maximum comfort and support eye health – a balance that is of great importance to the millions of people worldwide who wear vision aids as part of their daily lives.