A slit projector for generating slit illumination in an eye, including a light source, a slit forming unit and an imaging optical unit along a beam path. The invention facilitates improved freedom to operate in the treatment field. The slit projector includes a mirror arranged between the slit forming unit and the imaging optical unit. A corresponding positioning apparatus facilitates aligning the slit illumination in the eye for a therapy system with a surgical microscope and a slit projector. The positioning apparatus includes a holding element and a fastening element, which can be connected to the surgical microscope and the slit projector, respectively, and a pivoting element including a first connection, by use of which the pivoting element and the holding element are movably connected, and a second connection, by use of which the pivoting element and the fastening element are movably connected.

A shunt valve for removing biofluid from an eye of a user, the valve including a tubular body defining an inlet and a plurality of outlets formed through a wall of the tubular body; a plunger accommodated within the tubular body and fluidically coupled to the inlet; wherein the plunger is movable relative to the plurality of outlets; and an energized material coupled to the plunger and the tubular body; wherein the energized material is compressible to expose a portion of the plurality of outlets dependent on the pressure applied to the energized material.

Objective refraction error measuring apparatuses are known. Once the measurement is done, there is no known method for confirming if the measurements are correct. Disclosed is an apparatus wherein once the error is measured, the determined values of the error are used to set the characteristics of a tunable lens so as to correct the error in the vision of the subject. The objective error is measured again while the subject viewing through the tunable lens so set. Objective refraction error is again measured. If the error measured is now within predefined limits, the first measurement is deemed correct and the values are out put so that glasses with those values may be prescribed to the subject.