Contact lens and method for prevention of myopia progression
A method of slowing the progression of myopia in a person, comprises applying to the eye of the person contact lens or lenses each including a vision correction area for correcting in use the myopic vision of a wearer, and a myopic defocus area having a less negative focal power, to simultaneously present a controlled myopic defocus to the retina both when viewing in the distance and also when viewing at near. Contact lenses and their use are also claimed.
1. A method of slowing the progression of myopia in a person, comprising: applying to the eye or eyes of the person or prescribing for the person, a contact lens or lenses, each contact lens including a vision correction area comprising a focal power to correct the myopic vision of the person during distance viewing and to provide a clear retinal image during near viewing; and a myopic defocus area which comprises focal power less negative than the vision correction area focal power to simultaneously in use present a myopic defocused image to the person during both distance and near viewing, to thereby simultaneously present the eye or eyes of the person a clear retinal image and retinal myopic defocus during both distance and near viewing.
2. A method according to claim 1 comprising applying to the eye or eyes of the person or prescribing for the person, a contact lens or lenses the focal power of the myopic defocus area of which is up to 5 dioptres less negative than the focal power of the vision correction area.
3. A method according to claim 1 comprising applying to the eye or eyes of the person or prescribing for the person, a contact lens or lenses the focal power of the myopic defocus area of which is between about 1 and about 3 dioptres less negative than the focal power of the vision correction area.
4. A method according to claim 1 comprising applying to the eye or eyes of the person or prescribing for the person, a contact lens or lenses the focal power of the myopic defocus area of which is about 2 dioptres less negative than the focal power of the vision correction area.
5. A method according to claim 1 comprising applying to the eye or eyes of the person or prescribing for the person, a contact lens or lenses in which the myopic defocus area comprises two separate part-circular shaped areas which impinge onto the area of the surface of the contact lens from either side or from above and below and in which the balance of the lens comprises the vision correction area.
6. A method according to claim 1 comprising applying to the eye or eyes of the person or prescribing for the person, a contact lens or lenses in which the myopic defocus area comprises one half of the lens and the vision correction area comprises the other half of the lens.
7. A method according to claim 1 comprising applying to the eye or eyes of the person or prescribing for the person, a contact lens or lenses in which the vision correction area comprises a central ovaloid area of the lens and the myopic defocus area comprises the balance of the lens.
8. A contact lens, comprising: a vision correction area comprising a focal power to correct myopic vision of a person during distance viewing and to provide a clear retinal image during near viewing; and a myopic defocus area comprising a focal power less negative than the vision correction area focal power to simultaneously in use present a myopic defocused image to the person during both distance and near viewing, to thereby simultaneously present the eye or eyes of the person a clear retinal image and retinal myopic defocus during both distance and near viewing.
9. A contact lens according to claim 8 , wherein the vision correction area comprises a negative focal power, and the myopic defocus area comprises a focal power less negative than the vision correction area focal power.
10. A contact lens according to claim 8 wherein the focal power of the myopic defocus area of the lens is up to 5 dioptres less negative than the focal power of the vision correction area.
11. A contact lens according to claim 8 wherein the focal power of the myopic defocus area of the lens is between about 1 and about 3 dioptres less negative than the focal power of the vision correction area.
12. A contact lens according to claim 8 wherein the focal power of the myopic defocus area the lens is about 2 dioptres less negative than the focal power of the vision correction area.
13. A contact lens according to claim 8 in which the myopic defocus area comprises two separate part-circular shaped areas which impinge onto the area of the surface of the contact lens from either side or from above and below and in which the balance of the lens comprises the vision correction area.
14. A contact lens according to claim 8 in which the myopic defocus area comprises one half of the lens and the vision correction area comprises the other half of the lens.
15. A contact lens according to claim 8 in which the vision correction zone comprises a central ovaloid area of the lens and the myopic defocus area comprises the balance of the lens.
16. A method of manufacturing a contact lens system or kit for treating or slowing the progression of myopia in a patient, comprising: providing two or more contact lenses which may be the same or different, at least one of which comprises a vision correction area for correcting in use the myopic vision of the patient and a myopic defocus area for simultaneously presenting in use a myopic defocused image to the patient.
17. A method according to claim 16 , wherein the focal power of the myopic defocus area of which is up to 5 dioptres less negative than the focal power of the vision correction area.
18. A method according to claim 16 , wherein the focal power of the myopic defocus area of which is between about 1 and about 3 dioptres less negative than the focal power of the vision correction area.
19. A method according to claim 16 , wherein the focal power of the myopic defocus area of which is about 2 dioptres less negative than the focal power of the vision correction area.