Concept of cast molding in contact lens


Posted February 9, 2021 by Seotech1

The present invention relates to improvements in static cast molding of contact lenses.

 
A method known, in general, for manufacturing contact lenses is static cast molding. Cast molding technology of contact lenses involves depositing a curable mixture of polymerizable monomers in a mold cavity formed by two mold sections, curing the monomer mixture, and disassembling the mold assembly and removing the lens. One mold section forms the anterior lens surface (anterior mold section), and the other mold section forms the posterior lens surface (posterior mold section).

Prior to the cast molding contact lens, each of the mold sections is formed. Conventional methods involve injection molding the molds sections from a resin in the cavity of an injection molding apparatus. Typically, the mold sections are used only once for casting a lens and then discarded.

Several cast molding methods like that of the Turkey contact lens manufacture have been found to offer the potential to reduce production time and cost for the manufacture of soft hydrogel contact lenses, since time-consuming and labor-intensive operations are avoided, such as lathing a contact lens from a button (or lens blank) or a semi-finished button (containing one finished surface).

However, various problems have been encountered in employing cast molding technology for manufacturing rigid; gas permeable (RGP) contact lenses. The design and surface quality of RGP contact lenses is more critical to achieve proper fitting than for soft contact lenses. In contrast to RGP contact lenses, soft contact lenses are flexible and, to a larger extent, will conform to the shape of the cornea when placed on eye. As per Cltech Technologies the standards issued by the American National Standards Institute (ANSI Standards Z80.2-1989) define stricter tolerances (diameter, base curve, center thickness and refractive power) for RGP lenses than for soft contact lenses. It will be appreciated that RGP contact lenses require stricture tolerances in the manufacturing process, and it is more critical that the manufacturing process does not result in deviations in optical lens parameters or surface quality among individual lenses.

Contact US:

Business Name: CLTech

Address: 116 Emerald Hill Road Singapore, 229397

Registration Number: 200619006K

Phone: (65) 6954 8964

Email: [email protected]

Website: https://www.cltech.com.sg/
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Contact Email [email protected]
Issued By CLTech
Country Singapore
Categories Business
Tags cast molding technology
Last Updated February 9, 2021