It is well known that the eye’s lens focuses by changing shape. When muscles in the eye relax, the lens is pulled flat to focus on distant objects.

It is well known that the eye’s lens focuses by changing shape. When muscles in the eye relax, the lens is pulled flat to focus on distant objects. When they contract, the lens returns to a fatter shape, bringing closer objects into focus. These principles were used in design our autofocusing eyeglasses with variable optical power.

Our idea is to use elastic lens, which is similar to eye’s lens can change its optical power according to the viewing distance. One of the proposed technical solutions is based on the patented design of liquid-filled variable lenses. The distinctive feature of our variable eyeglasses is in the using of native human reflex for optical power control of the liquid filled elastic lenses.

( J. Bekerman , A. Bekkerman “Apparatus and method for eyesight rehabilitation”. Patent Application. PCT/IL 2003/000721, WO2004/023167 A2. ) On the Fig. 4an isometric view of multifocal autofocusing eyeglasses is shown. Multifocal eyeglasses comprise a spectacle-like rim 1 for wearing the spectacles on a user’s nose and two liquid lenses 2. The transparent optical liquid is confined between two elastic membranes that are held at their circumference in a corresponding recess in the rim 1. The variable lens is essentially the closed hydrostatic system, that comprising two connected reservoirs one of which is the elastic lens 2 and the second one an optical liquid container.

3.   How it is working ? We used the gravitation force as the means of pushing the liquid from container into the lens cavity. Since the membranes are made from an elastic material, the curvature of the lens is adjustable and determined by the pressure of the liquid confined between the membranes. When the pressure of the liquid is greater, the curvature of the liquid lens is higher. The variation of the membranes curvature in fact leads to variation the optical power of the lens. When the person is shift one gaze from far objects to close ones the eyeglasses automatically change its optical power. The human brain estimates the sharpness of the picture focused on the retina and gives the command for head muscles to choose an optimal position. At the same time, the eye muscles also try to take an optimal condition for the better vision. One of the most important advantages of liquid filled lenses is their wide field of view in comparison with progressive multifocal lenses. It makes possible non-strained and non-distorted side vision in the reading condition. Actually, this is the new technology of the cooperative interaction of adaptive optics and biological system of human eyes. This technology provides comfortable (non-strain) seeing of objects at any distances. Relaxed vision gives the feeling of native (as if youthful) sight. Such non-strained state of eyes gives also good motivation for activation of all physiological processes in the biological system of vision. As the result person gradually gains the experience of normal visual work of eyes.