A cheiroscope is a device used to train binocular vision and designed so that each eye can see a different image.
The patient places forehead on the support and looks through convex lens. One eye is aimed at a diagonal mirror, and the other on the sheet of paper. The convex lens create conditions of looking far away, because the pictures are in the focus of the lens. The apparatus is ready for training both left and right-handed children.
A simple picture is placed in a holder, preferably with outlines of objects, drawn with bold, black line, e.g. a house, a tree, etc. The exercise is difficult, which is why simple pictures are used. The task of the patient is to copy the picture on the sheet of paper precisely following its outlines. The picture that is fixated with the leading eye or the line drawn with the strabismic eye or a pencil fixated with this eye often disappears. The patient needs to blink several times to prevent fatigue and allow the exercise to be continued.