Method to establish the size of the zones of near A.sub.c, far A.sub.L and intermediate A.sub.i vision of a progressive lens by generating, thanks to virtual reality, a gaze map of the user while following a stimulus in at least two planes at two different distances. Once the gaze maps have been made in those two planes or more, the area of each zone is calculated from the maximum horizontal and vertical amplitudes and the points of maximum frequency. In this way, the lens is adapted to the way a user looks.

A head mounted display includes a combiner configured to receive display light from a micro-display. The world-facing surface of the combiner has a curvature that corresponds to a user's vision correction prescription. The head mounted display also includes a corrective layer having a second curvature that corresponds to the user's vision correction prescription. The corrective layer is disposed on the eye-facing surface of the combiner such that the focal point of the display light is adjusted for the specific user as the display light exits the combiner towards the user's eye.

A progressive power lens and a technique associated therewith, wherein C.sub.F and Ax.sub.F are achieved in a distance portion and C.sub.N and Ax.sub.N are achieved in a near portion in a state in which: a basic progressive surface on which no astigmatic power is set in the distance portion, the near portion, and an intermediate portion; a curvature distribution of a set α (k1α, k2α) of two principal curvatures having different sizes that is uniformly added to the distance portion, the near portion, and the intermediate portion, and that achieves C.sub.F and Ax.sub.F in the distance portion; and a curvature distribution of a set β (k1β, k2β) of two principal curvatures having different sizes that is different from the curvature distribution of the set α, and in which an absolute value (lk1β-k2βl) of a principal curvature difference increases in a predetermined direction, are combined.

A method for determining an optical system intended to equip a person on the basis of the adaptability of the person to a visual and/or proprioceptive modification of his environment, the method including a person visual behaviour parameter providing, during which a person visual behaviour parameter indicative of the visual behaviour of the person relative to a given state of the environment is provided; a reference value providing, during which a first value of the person visual behaviour parameter corresponding to a reference state of the environment is provided; a visual and/or proprioceptive modification providing, during which a visual and/or proprioceptive modification of the reference state of the environment is provided so as to define a modified state of the environment; and determining, during which an optical parameter of the optical system is determined based on the first value of the person visual behaviour parameter and on a second value of the person visual behaviour parameter associated with the modified state of the environment.

A lens element to be worn by a wearer and to provide a refractive power based on a prescription of the wearer is provided for correcting an abnormal refraction of the eye of the wearer, the lens element including: an optical microstructure having an optical function of not focusing an image on a retina of the eye of the wearer so as to slow down progression of the abnormal refraction of the eye of the wearer, in which a modulation transfer function of the lens element is greater or equal to 0.07 over a range of spatial frequencies from 10 to 25 cycles per degree, when measured through the optical microstructure for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element. A computer-implemented method for determining a lens element to be worn by a wearer is also provided.

A lens element to be worn by a wearer and to provide a refractive power based on a prescription of the wearer is provided for correcting an abnormal refraction of the eye of the wearer, the lens element including: an optical microstructure having an optical function of not focusing an image on a retina of the eye of the wearer so as to slow down the progression of the abnormal refraction, in which the modulation transfer function of the lens element, for peripheral vision, is less than or equal to 0.8 over a range of spatial frequency comprised from 3 to 7 cycles per degree, when measured through the optical microstructure for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element. A computer-implemented method for determining a lens element to be worn by a wearer is also provided.

Methods and devices to identify contact lens wearers predisposed to contact lens discomfort are described. The methods and devices involve obtaining a tear film sample from a person and determining an amount of interleukin-17A present in the tear film sample.

Systems and methods for visual acuity calculation including consideration of a combination of ocular aberrations and lens aberrations are disclosed. One method includes obtaining ocular aberration data and introducing a correction in the defocus term of the ocular aberration data to account for longitudinal chromatic aberration. Lens aberration data is obtained, including performing raytracing through the ophthalmic lens of the patient. Correction to tilt and defocus terms of the lens aberration data is made to account for transverse and longitudinal chromatic aberrations. Polychromatic Point Spread Functions (PSFs) associated to the ocular aberration data and lens aberration data are used to generate retinal images. Retinal sampling is applied to the retinal images, followed by filtering and normalizing the retinal images is also performed. Finally, a maximum visual acuity value is determined. The methods are performed using one or more computing devices.

One embodiment is directed to a system comprising a head-mounted member removably coupleable to the user's head; one or more electromagnetic radiation emitters coupled to the head-mounted member and configured to emit light with at least two different wavelengths toward at least one of the eyes of the user; one or more electromagnetic radiation detectors coupled to the head-mounted member and configured to receive light reflected after encountering at least one blood vessel of the eye; and a controller operatively coupled to the one or more electromagnetic radiation emitters and detectors and configured to cause the one or more electromagnetic radiation emitters to emit pulses of light while also causing the one or more electromagnetic radiation detectors to detect levels of light absorption related to the emitted pulses of light, and to produce an output that is proportional to an oxygen saturation level in the blood vessel.

Systems and methods for creating and/or manufacturing progressive lenses (e.g., bifocal, multifocal, and so on) having ocular side (e.g., back side or surface) lens segments, are described. For example, the systems and methods may apply round lens segments to ocular sides or surfaces of progressive lenses, providing the lenses with specializing vision lens segments and/or power enhancement lens segments, which may combine with front surface power additions provided by the multifocal lens segments applied to the front surfaces of the lenses.