Abstract: In accordance with a first aspect of the present disclosure, a communication device is provided, comprising: a plurality of antennas; a communication unit configured to execute ranging sessions with an external communication counterpart through said antennas; an antenna selection unit configured to select a specific antenna from said plurality antennas for carrying out one or more of said ranging sessions, wherein the antenna selection unit is configured to select said specific antenna in dependence on one or more parameters indicative of a communication quality between the antennas and the external communication counterpart. In accordance with a second aspect of the present disclosure, a corresponding method of operating a communication device is conceived. In accordance with a third aspect of the present disclosure, a computer program is provided for carrying out said method.

Abstract: An attachment for microscopes, in particular for stereomicroscopes, facilitates a contact-free viewing of an eye freely movable by the patient, in particular the fundus of the eye. Such an attachment must be easily and quickly attachable to the microscope and must deliver an image section of up to 120.degree.. Moreover, the free movability of the eye must be assured and the attachment must also at high temperature be able to be sterilized quickly, without influencing the wearability of the attachment. This is achieved by an attachment having two lenses or lens systems, the distance between the systems being adjustable and the systems replacing the objective lens of the microscope. The housing of the attachment can be connected to the microscope through a screw or bayonetlike coupling.

Abstract: A stereomicroscope for use in performing surgeries, in particular eye surgeries, which has a collecting lens common to both beam paths and has for each beam path an objective and an ocular tube with two reversing prisms with adjustable interocular distance, which ocular tubes form a telescope. In order to produce, at an angled beam path with the help of the panorama funduscopy, an upright and unreversed image, between the objective (7) and the ocular tubes (11, 12) which contain the telescope is provided a double-refracting, reflecting system (4, 19, 20) which delivers a turned, unreflected image and covers both beam paths, which system is arranged in the stereomicroscope so that same can be exchanged with a 90.degree. prism which is constructed with the same optical path length and covers both beam paths.