Abstract: A total reflection lens includes a first end surface with a first diameter, and a second end surface parallel to the first end surface and with a second diameter. The second diameter is greater than the first diameter, and the two end surfaces are connected via a convexly curved lateral surface. A recess adjoining the first end surface and pointing in the direction of the second end surface is located between the first end surface and the second end surface. The recess has at least two boundary surface portions, pointing in the direction of the second end surface and separate from one another, for refracting light in the direction of the lateral surface.

Abstract: An ophthalmoscope for examining eyes, includes: a housing; a converting device for converting light into an electrical signal; and an objective, the objective comprising a lens and/or a mirror. The objective has a convexly curved focus area, a convexly curved image surface of an eye being able to be sharply imaged onto the converting device by means of the objective.

Abstract: A self-piercing blind rivet is provided for apposing biological tissue together with a device for setting the same, especially through the instrumental channel of a flexible endoscope. Without the help of further instruments, it is possible to fix, approximate and appose tissue layers, the contact force while connecting the tissue layers being adjustable. The rivets are stored in the setting device, so that they can be applied in order. The rivet and setting device enable the surgeon to combine tissue discontinuities conveniently by means of an endoscope. The surgical procedure is simplified further because the rivets can remain in the body.

Abstract: A self-piercing blind rivet is provided for apposing biological tissue together with a device for setting the same, especially through the instrumental channel of a flexible endoscope. Without the help of further instruments, it is possible to fix, approximate and appose tissue layers, the contact force while connecting the tissue layers being adjustable. The rivets are stored in the setting device, so that they can be applied in order. The rivet and setting device enable the surgeon to combine tissue discontinuities conveniently by means of an endoscope. The surgical procedure is simplified further because the rivets can remain in the body.