Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have displays that produce images. Positioners may be used to move the displays relative to the eye positions of a user's eyes. An adjustable optical system may include tunable lenses such as tunable cylindrical liquid crystal lenses. The displays may be viewed through the lenses when the user's eyes are at the eye positions. A sensor may be incorporated into the head-mounted display to measure refractive errors in the user's eyes. The sensor may include waveguides and volume holograms, and a camera for gathering light that has reflected from the retinas of the user's eyes. Viewing comfort may be enhanced by adjusting display positions relative to the eye positions and/or by adjusting lens settings based on the content being presented on the display and/or measured refractive errors.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have displays that produce images. Positioners may be used to move the displays relative to the eye positions of a user's eyes. An adjustable optical system may include tunable lenses such as tunable cylindrical liquid crystal lenses. The displays may be viewed through the lenses when the user's eyes are at the eye positions. A sensor may be incorporated into the head-mounted display to measure refractive errors in the user's eyes. The sensor may include waveguides and volume holograms, and a camera for gathering light that has reflected from the retinas of the user's eyes. Viewing comfort may be enhanced by adjusting display positions relative to the eye positions and/or by adjusting lens settings based on the content being presented on the display and/or measured refractive errors.

Abstract: A head-mounted device may have a display that displays computer-generated content for a user. The head-mounted device may have an optical system that directs the computer-generated image towards eye boxes for viewing by a user. The optical system may be a see-through optical system that allows the user to view a real-world object through the optical system while receiving the computer-generated image or the optical system may include a non-removable lens and a removable vision correction lens through which an opaque display is viewable. The optical system may include a removable lens. The removable lens may serve as a custom vision correction lens to correct for a user's vision defects. The optical system may have a projection bias lens that places computer-generated content at one or more desired virtual image distances and a corresponding compensation bias lens.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.

Abstract: An electronic device may include a display that displays virtual reality content. Control circuitry may estimate a brightness adaptation state of a user that is wearing the electronic device. The control circuitry may select a tone mapping curve and brightness level for the virtual reality content based on the user's adaptation state. To estimate the user's adaptation state, the control circuitry may gather ambient light information from an ambient light sensor, may gather physiological attributes of the user such as blink rate, pupil size, and eye openness from a camera, and may gather gaze position information from gaze detection circuitry. The control circuitry may optimize the brightness of the display based on the user's current adaptation state, or the control circuitry may shift the brightness of the display away from the user's adaptation level to help guide the adaptation state to the desired level.

Abstract: A head-mounted device may have a display that displays computer-generated content for a user. The head-mounted device may have an optical system that directs the computer-generated image towards eye boxes for viewing by a user. The optical system may be a see-through optical system that allows the user to view a real-world object through the optical system while receiving the computer-generated image or the optical system may include a non-removable lens and a removable vision correction lens through which an opaque display is viewable. The optical system may include a removable lens. The removable lens may serve as a custom vision correction lens to correct for a user's vision defects. The optical system may have a projection bias lens that places computer-generated content at one or more desired virtual image distances and a corresponding compensation bias lens.

Abstract: An electronic device may include a display that displays virtual reality content. Control circuitry may estimate a brightness adaptation state of a user that is wearing the electronic device. The control circuitry may select a tone mapping curve and brightness level for the virtual reality content based on the user's adaptation state. To estimate the user's adaptation state, the control circuitry may gather ambient light information from an ambient light sensor, may gather physiological attributes of the user such as blink rate, pupil size, and eye openness from a camera, and may gather gaze position information from gaze detection circuitry. The control circuitry may optimize the brightness of the display based on the user's current adaptation state, or the control circuitry may shift the brightness of the display away from the user's adaptation level to help guide the adaptation state to the desired level.

Abstract: A head-mounted device may have a display that displays computer-generated content for a user. The head-mounted device may have an optical system that directs the computer-generated image towards eye boxes for viewing by a user. The optical system may be a see-through optical system that allows the user to view a real-world object through the optical system while receiving the computer-generated image or the optical system may include a non-removable lens and a removable vision correction lens through which an opaque display is viewable. The optical system may include a removable lens. The removable lens may serve as a custom vision correction lens to correct for a user's vision defects. The optical system may have a projection bias lens that places computer-generated content at one or more desired virtual image distances and a corresponding compensation bias lens.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.

Abstract: A head-mounted device may have a display that displays computer-generated content for a user. The head-mounted device may have an optical system that directs the computer-generated image towards eye boxes for viewing by a user. The optical system may be a see-through optical system that allows the user to view a real-world object through the optical system while receiving the computer-generated image or the optical system may include a non-removable lens and a removable vision correction lens through which an opaque display is viewable. The optical system may include a removable lens. The removable lens may serve as a custom vision correction lens to correct for a user's vision defects. The optical system may have a projection bias lens that places computer-generated content at one or more desired virtual image distances and a corresponding compensation bias lens.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have displays that produce images. Positioners may be used to move the displays relative to the eye positions of a user's eyes. An adjustable optical system may include tunable lenses such as tunable cylindrical liquid crystal lenses. The displays may be viewed through the lenses when the user's eyes are at the eye positions. A sensor may be incorporated into the head-mounted display to measure refractive errors in the user's eyes. The sensor may include waveguides and volume holograms, and a camera for gathering light that has reflected from the retinas of the user's eyes. Viewing comfort may be enhanced by adjusting display positions relative to the eye positions and/or by adjusting lens settings based on the content being presented on the display and/or measured refractive errors.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.