VARIABLE FOCUS SPECTACLES WITH BIPOLAR LENS UNITS AND FRONT MASKING LENSES

Variable focus spectacles including bipolar variable focus lens units and a front masking lens disposed in front of each variable focus lens unit. Each bipolar variable focus lens unit has a transparent rigid member, a transparent distensible membrane, a membrane support on which the membrane is mounted, a transparent liquid of a fixed volume filling in a sealed space between the rigid member and the membrane, and is connected to a bidirectional actuating mechanism for urging the membrane support and the rigid member to move toward and away from each other. Each front masking lens may have any suitable shape so long as its front surface is convex and reflections off that front surface typically dominate reflections off the underlying distensible membrane.