Progressive lens elements and methods for designing and using same

A method of designing a progressive ophthalmic lens element, the lens element including a lens surface having:

• an upper viewing zone having a surface power to achieve a refracting power corresponding to distance vision;
• a lower viewing zone having a greater surface power than the upper viewing zone to achieve a refracting power corresponding to near vision;
• a corridor of relatively low surface astigmatism connecting the upper and lower zones, said corridor having a surface power varying from that of the upper viewing zone to that of the lower viewing zone;
• wherein the lens element is formed by
• (a) providing a mathematical or numerical representation of a progressive lens surface having a distance viewing zone, a near viewing zone and an eye path corridor wherein the eye path corridor is centered on a line of approximately zero surface astigmatism and has a progressively varying refractive power;
• (b) rotating and horizontally off-setting the representation of the lens surface below the distance viewing zone in a nasal direction to account for accommodative reserve and the variation of inset caused by the progressive power increase in the eye path corridor;
• (c) rotating the representation of the lens surface below the eye path corridor in a temporal direction;
• (d) modifying the representation of the lens surface on the basis of the location of horizontal mid-points between nasal and temporal isoastigmatism curves of a selected dioptric value;
• and
• (e) forming a lens surface corresponding to the modified representation of the lens surface.

A series of progressive ophthalmic lens elements, each lens element including a lens surface having:

• an upper viewing zone having a surface power to achieve a refracting power corresponding to distance vision;
• a lower viewing zone having a greater surface power than the upper viewing zone to achieve a refracting power corresponding to near vision;
• and
• a corridor of relatively low surface astigmatism connecting the upper and lower viewing zones, said corridor having a surface power varying from that of the upper viewing zone to that of the lower viewing zone;
• the progressive ophthalmic lens series including at least three sets of lens elements, each set having a different base power suitable for use in providing a range of distance prescriptions, wherein the width of the upper viewing zone is an increasing function of base power.

A series of progressive ophthalmic lens elements, each lens element including a lens surface having:

• an upper viewing zone having a surface power to achieve a refracting power corresponding to distance vision;
• a lower viewing zone having a greater surface power than the upper viewing zone to achieve a refracting power corresponding to near vision;
• and
• a corridor of relatively low surface astigmatism connecting the upper and lower viewing zones, said corridor having a surface power varying from that of the upper viewing zone to that of the lower viewing zone;
• the progressive ophthalmic lens series including
• a first set of lens elements having at least one base curve suitable for use in providing a range of distance prescriptions for myopes;
• a second set of lens elements having at least one base curve suitable for use in providing a range of distance prescriptions for emmetropes, and
• a third set of lens elements having at least one base curve suitable for use in providing a range of distance prescriptions for hyperopes;
• each set containing elements with different addition power, wherein lens elements from different sets having substantially the same addition power have shared optical characteristics in at least the upper viewing zone, such that the width of the upper viewing zone is an increasing function of base power.