Contact lens
AssigneeBritish Technology Group Limited
InventorsWilliam E. Seden, Ronald S. Hamilton
Life of this patent
Estimating the term…
Abstract
To improve its gas-permeability, a contact lens, which may be of any normal material, even a gas-impermeable material such as polymethylmethacrylate, is microperforated with 66000 holes distributed in equispaced sectors leaving unperforated the central (optically important) part and the outermost rim of the lens. With a smaller hole size, some one million holes can be accommodated. In a modification, some or all of the holes go only part way through the thickness of the contact lens.
Claims42
A contact lens comprising a central area of diameter of at least 5 mm and holes of exit diameter of at least one micron and an exit area not exceeding 5.times.10.sup.-4 mm.sup.2 going part or all the way from one lens surface to the other, said holes being distributed so that no holes are present in said central area, said holes being in sufficient number to account for at least 5% of the area of the lens.
Dependencies are inferred from the claim text.