EP0367513A2 — Contact lens cast moulding

Claim 1

Independent Claim 130 words

A method of cast moulding a contact lens comprising polymerising a monomer in a mould having a mould cavity between relatively movable male and female mould surfaces and a rigid shoulder for forming a peripheral seal between the two mould surfaces to close the cavity, at least one of the mould surfaces being flexible under a loading pressure, said method being characterised by closing said mould cavity with monomer filling the cavity, applying a superatmospheric pressure in a pressure vessel so that said loading pressure acts on the mould surfaces and forms a pressurised seal around said rigid shoulder, subsequently curing the monomer whereby said loading pressure causes deflection of one of the mould surfaces to maintain the surfaces in contact with the lens as the monomer shrinks during polymerisation.

Claim 2

Independent Claim 130 words

A method of cast moulding a contact lens comprising polymerising a monomer in a mould having a mould cavity between relatively movable male and female mould surfaces and a rigid shoulder for forming a peripheral seal between the two mould surfaces to close the cavity, at least one of the mould surfaces being flexible under a loading pressure, said method being characterised by closing said mould cavity with monomer filling the cavity, applying a superatmospheric pressure in a pressure vessel so that said loading pressure acts on the mould surfaces and forms a pressurised seal around said rigid shoulder, subsequently curing the monomer whereby said loading pressure causes deflection of one of the mould surfaces to maintain the surfaces in contact with the lens as the monomer shrinks during polymerisation.

Claim 3

Dependent Claim 54 words

A method according to claim 1 wherein the male and female mould surfaces are formed on respective mould parts arranged to engage each other as a sliding piston and cylinder device, said application of a superatmospheric pressure being applied to both mould parts thereby urging the male and female mould surfaces towards each other.

Claim 4

Independent Claim 68 words

A method of cast moulding a contact lens comprising polymerising a monomer in a mould cavity between a male mould surface in a first mould part and a female mould surface in a second mould part, opening the mould to expose the cast lens while supported on said male mould surface, and sealing the lens in a package by sealing a cover member onto said first mould part.

Claim 5

Independent Claim 68 words

A method of cast moulding a contact lens comprising polymerising a monomer in a mould cavity between a male mould surface in a first mould part and a female mould surface in a second mould part, opening the mould to expose the cast lens while supported on said male mould surface, and sealing the lens in a package by sealing a cover member onto said first mould part.

Claim 6

Independent Claim 44 words

A method according to any one of claims 1 to 3 in which monomer is fed to said mould cavity while the female mould surface is facing upwardly, and inverting the mould so that on opening the mould said male surface is facing upwardly.

Claim 7

Independent Claim 78 words

A method according to any one of claims 1 to 4 wherein on opening the mould the cast lens is supported on the male mould surface surrounded by a cup member having an annular wall projecting above the lens, hydrating fluid is supplied to the cup member to hydrate the lens while supported on the male surface and a cover is sealed onto the cap member above the lens to form a packaged lens in the cup member.

Claim 8

Independent Claim 100 words

A method according to any one of the preceding claims in which said first and second mould parts are slidable relative to each other in engagement as a piston and cylinder device to open and close the mould and in which the first mould part is formed as a cup member having a base surrounded by an upstanding annular wall which engages said second mould part, the male mould surface being formed on said base spaced inwardly from the annular wall to provide a trough into which hydrating fluid is fed to hydrate the lens when the mould is opened.

Claim 9

Dependent Claim 24 words

A method according to claim 5 or claim 6 in which the cover member is sealed onto an upper edge of said annular wall.

Claim 10

Dependent Claim 102 words

A mould for use in a method according to any one of the preceding claims, which mould comprises a first mould part having a male mould surface and a second mould part having a female mould surface, each of said mould parts having a base on which the respective mould surface is formed and an annular wall extending upwardly from the base, the annular walls of the first and second mould parts being arranged to engage each other as a sliding fit whereby the two mould parts may be moved as a piston and cylinder device to open and close the mould.

Claim 11

Dependent Claim 48 words

A mould according to claim 8 in which the male mould surface is formed on the base of said first mould part spaced inwardly from the annular wall of the first mould part so as to provide a trough within the annular wall surrounding said male mould surface.

Claim 12

Dependent Claim 37 words

A mould according to either of claims 8 or 9 in which the annular wall of said first mould part is formed with a flange at its upper end onto which a sealing cover may be sealed.

Claim 13

Dependent Claim 27 words

A mould according to any one of claims 8 to 10 in which the annular wall on the first mould part extends above said male mould surface.

Claim 14

Independent Claim 32 words

A method according to any one of the preceding claims wherein the male surface is flame polished to assist in retaining the lens on the male surface when the mould is opened.

Claim 15

Independent Claim 33 words

A method according to any one of claims 1 to 11 wherein the female surface is flame polished to assist in retaining the lens on the female surface when the mould is opened.

Claim 16

Independent Claim 38 words

A method according to any one of the preceding claims wherein after opening the mould the lens is held exposed on one mould surface and is subject to an additional treatment step on the exposed outer lens surface.

Claim 17

Dependent Claim 16 words

A method according to claim 14 wherein said additional treatment step comprises tinting, colouring or printing.

Claim 18

Dependent Claim 36 words

A method according to claim 14 or claim 15 wherein said additional treatment steps comprises the formation of one or more holes through the thickness of the lens by application of a short wavelength laser beam.

Claim 19

Dependent Claim 14 words

A method according to claim 16 wherein said beam is an excimer laser beam.

Claim 20

Dependent Claim 25 words

A method according to claim 16 or claim 17 in which a plurality of holes are formed to form a controlled porosity of the lens.

Claim 21

Dependent Claim 24 words

A method according to claim 16 or claim 17 in which a plurality of holes are formed to provide controlled durability of the lens.

Claim 22

Dependent Claim 27 words

A method according to claim 18 in which a controlled dosage of drug or other medical compound is introduced into the porosity formed by the hole formation.

Claim 23

Independent Claim 111 words

A method of cast moulding a contact lens comprising polymerising a monomer in a mould cavity between a male and female mould surface, opening the mould to expose the cast lens while supported on one of the mould surfaces, perforating the lens by application of a laser beam to provide a controlled porosity of the lens, applying a drug or other medication to the lens so that the dosage taken up by the lens is determined by the extent of porosity formed and the concentration of the drug or medication, and sealing the lens in a package by sealing a cover member onto the part of the mould supporting said lens.

Claim 24

Independent Claim 111 words

A method of cast moulding a contact lens comprising polymerising a monomer in a mould cavity between a male and female mould surface, opening the mould to expose the cast lens while supported on one of the mould surfaces, perforating the lens by application of a laser beam to provide a controlled porosity of the lens, applying a drug or other medication to the lens so that the dosage taken up by the lens is determined by the extent of porosity formed and the concentration of the drug or medication, and sealing the lens in a package by sealing a cover member onto the part of the mould supporting said lens.

Claim 25

Dependent Claim 19 words

A method according to claim 21 wherein said lens is hydrated after said dosage with drug or other medication.

Claim 26

Dependent Claim 18 words

A package comprising a hyrated dosed cast lens formed by the process of claim 21 or claim 22.

Claim 27

Dependent Claim 74 words

A method according to claim 21 wherein on opening the said mould the cast lens is supported on a male mould surface surrounded by a cup member having an annular wall projecting above the lens, hydrating fluid is supplied to the cup member to hydrate the lens while supported on the male surface and a cover is sealed onto the cap member above the lens to form a packaged lens in the cup member.

Claim 28

Independent Claim 19 words

A method according to any one of claims 21 to 24 in which said laser is an excimer laser.

Contact lens cast moulding

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag