Optical device adapted to be worn by a wearer

An optical device adapted to be worn by a wearer, the wearer having a prescription for at least one eye, the optical device comprising:

• an active programmable lens having an adjustable optical power and extending between at least one eye of the wearer and a real world scene when the optical device is worn by the wearer, the adjustable optical power depending on the prescription of said at least one eye of the wearer and being relative to a vision distance and a vision direction of said at least one eye of the wearer;
• a vision sensor adapted to measure vision data relating to the vision distance and vision direction of said at least one eye of the wearer using the optical device;
• and
• an optical power controller comprising:
• a memory storing at least computer executable instructions and adapted to store vision data measured by the vision sensor and at least two predetermined optical power states, each predetermined optical power state corresponding to an optical power relative to a range of vision distance and/or vision direction of said at least one eye of the wearer, and
• a processor for executing the stored computer executable instructions so as to control the adjustable optical power of the active programmable lens,
• wherein the computer executable instructions comprise instructions for adjusting the adjustable optical power of the active programmable lens from one predetermined optical power state to the other when the vision data indicate a vision distance and/or vision direction passing from the range of distance and direction of one predetermined optical power state to another, an adjustment resolution of the adjustable optical power of the active programmable lens being smaller than or equal to 0.25D,
• wherein the active programmable lens is a Fresnel lens and wherein the computer executable instructions comprise instructions for adjusting at least one prismatic optical power from one predetermined optical power state to another so as to move a central ring upon the vision direction of said at least one eye of the wearer,
• wherein the active programmable lens comprises Fresnel rings to provide a large field of view, and wherein an optical function of the active programmable lens is refocused when the vision direction of the eye of the wearer for the central vision approaches or exceeds a predefined Fresnel ring boundary, and
• wherein the computer executable instructions comprise instructions for adjusting the adjustable optical power only if the vision data indicate that the vision distance and/or vision direction remains within a new range for a predetermined duration.