Single vision lenses
View Patent ↗Optical lens element with a prescription zone, suitable for use in wraparound or protective type eyewear. The element may also include a peripheral vision zone, with no prismatic jump between the zones. Design methods for the prescription zone include temporally rotating a prescription section about a vertical axis through the optical center thereof, and/or decentring the optical axis of said prescription section relative to the geometric axis thereof, and providing partial surface correction for astigmatic and/or mean power errors. For prescription powers in the range −6.0 to +6.0 diopters with 0 to 3 cyl, the optical lens element may be designed such that its front surface can be mounted in a frame of constant curvature of at least 5.0 diopters, with its back surface providing good clearance from temples and eyelashes. Applications include ophthalmic sunglass lenses.
1. Spectacles including
a spectacle frame of the wrap-around type adapted to receive a pair of ophthalmic lenses such that each lens is rotated temporally about a vertical axis through the optical center thereof; and
a pair of ophthalmic lenses, each lens including
a front and back surface together forming a prescription (Rx) zone and
a peripheral temporal zone,
the front and/or back surface bearing a surface correction to at least
partially adjust for errors including astigmatic errors.
2. Spectacles according to claim 1 , wherein the lens provides true Rx correction in the prescription (Rx) zone for a wearer extends beyond 50° off axis and optionally terminating in a peripheral temporal zone, that provides clear perception of objects in the peripheral area of human vision and avoids prismatic jump from the prescription zone to the peripheral temporal zone.
3. Spectacles according to claim 1 , wherein each lens includes a non-prescription peripheral temporal zone.
4. Spectacles according to claim 1 , wherein the optical axis is decentered relative to the geometric axis of the lens element.
5. Spectacles according to claim 4 , wherein the optical axis is decentered vertically relative to the geometric axis of the lens element to at least partially compensate for pantoscopic tilt.
6. Spectacles according to claim 3 , wherein the optical axis is decentered horizontally relative to the geometric axis of the lens element to provide for prismatic correction.
7. Spectacles according to claim 1 , wherein the lens provides true Rx correction in the prescription zone for a wearer not greater 50° off axis.
8. Spectacles according to claim 5 , wherein the lens provides true Rx correction in the prescription zone for a wearer beyond 50° off axis and optionally terminating in a peripheral temporal zone, that provides clear perception of objects in the peripheral area of human vision and avoids prismatic jump from the prescription zone to the peripheral temporal zone.