Abstract: The perimeter includes a screen, a light source assembly, projection optics, and an adjustable beam deflector. The projection optics includes an adjustable lens having a focal length that can be changed by the control unit of the device. The projection optics further includes a projection lens element. The focal length of the adjustable lens is being changed as a function of the location of the stimulus light spot, thereby compensating for the location-dependent length of the optical path from the projection optics to the screen. The distance between the projection lens element and the adjustable lens is equal to the focal length of the projection lens element, which makes the spot size independent on the location.

Abstract: Image exposure in an ophthalmic microscope device is controlled by first recording a camera image with the camera of the microscope using first exposure parameters. Edge detection, e.g., based on convolution using a discrete differential operator, is then used to identify regions where the image has high and low edge densities. A brightness parameter of the camera image is calculated by weighing the pixel brightness in the regions with increased edge density more strongly than in the other regions. The brightness parameter is then used to control the exposure parameters of the microscope.

Abstract: Image exposure in an ophthalmic microscope device is controlled by first recording a camera image with the camera of the microscope using first exposure parameters. Edge detection, e.g., based on convolution using a discrete differential operator, is then used to identify regions where the image has high and low edge densities. A brightness parameter of the camera image is calculated by weighing the pixel brightness in the regions with increased edge density more strongly than in the other regions. The brightness parameter is then used to control the exposure parameters of the microscope.

Abstract: An eye examining instrument comprises a projection device and a concave screen. The eye examining instrument furthermore comprises a convex reflector, wherein an image can be projected by the projection device onto the convex reflector and reflected by the convex reflector onto the concave screen.

Abstract: An eye examining instrument comprises a projection device and a concave screen. The eye examining instrument furthermore comprises a convex reflector, wherein an image can be projected by the projection device onto the convex reflector and reflected by the convex reflector onto the concave screen.