Bifocal contact lenses
AssigneeN.G. Trustees & Nominees, Ltd.
InventorJohn T. de Carle
Life of this patent
Estimating the term…
Abstract
A bifocal contact lens is described wherein at least the major viewing area is divided into a multiplicity of near and distant vision viewing zones, each near vision zone being adjacent to a distant vision zone or middle distance zone and there being at least 3 viewing zones in all, whereby the wearer is able to look through at least 2 zones of different power simultaneously. Normally the lens has at least 2 of each kind of viewing zone and the total surface area of the distant vision zones is substantially equal to the total surface area of the near vision zones.
Claims17
A bifocal contact lens wherein at least the major viewing area is divided into a plurality of non-concentric near and distant vision zones, each near vision zone being adjacent to a distant vision zone;
- there being between at least about 2 zones of each kind in said major viewing area, and wherein the relative areas of the zones are such that in use substantially equal amounts of light enter the eye through the near vision zones and through the distant vision zones respectively.
A bifocal contact lens having a major viewing area which is divided into a plurality of non-concentric near and distant vision zones wherein:
- (a) each near vision zone is adjacent to distant vision zone,
- (b) there being between about 2 and about 8 zones of each kind in said major viewing area,
- (c) the ratio of the total area of the distant vision to the near vision zones being from about 60:40 to about 40:60, and
- (d) the distant vision zones comprise a plurality of generally circular areas distributed over said major viewing area.
A bifocal contact lens having a viewing area which is divided into sectors radiating outwardly from an axis of the lens wherein adjacent sectors constitute near and distant vision zones having a first power and a second power respectively and wherein the ratio of the total area of the near vision zones to the total area of the distant vision zones is from about 60:40 to 40:60.
Dependencies are inferred from the claim text.