Compensation of Presbyopia With the Light Sword Lens.

Purpose: We present the first physiological evaluation of the use of the light sword lens (LSL) for presbyopia compensation. The LSL is an axially asymmetric optical element designed for imaging with extended depth of focus. Methods: A monocular visual simulator setup is implemented to measure visual acuity (VA). Physiological presbyopia is "mimicked" in human subjects by paralysis of the ciliary muscle, using topical application of a muscarinic antagonist. The effect of a contact lens-configured LSL on the mimicked presbyopia visual system is evaluated by measuring VA as a function of target vergence. The ability of the LSL to compensate presbyopia for 2 photopic luminance values was also analyzed. Results: The average VA values for 11 subjects suggest that the LSL can compensate for presbyopia across a wide range of target vergences for which the LSL was designed (-3 to 0 D). However, the proposed corrector element causes a loss of distance VA. The mean logMAR VA in that target vergence range was 0.07. The VA curves also show that luminance does not affect the expected behavior of the LSL-corrected presbyopic eye. Conclusions: These results indicate that the LSL has significant potential as a visual aid for presbyopia.

Noise-free recovery of optodigital encrypted and multiplexed images.

We present a method that allows storing multiple encrypted data using digital holography and a joint transform correlator architecture with a controllable angle reference wave. In this method, the information is multiplexed by using a key and a different reference wave angle for each object. In the recovering process, the use of different reference wave angles prevents noise produced by the nonrecovered objects from being superimposed on the recovered object; moreover, the position of the recovered object in the exit plane can be fully controlled. We present the theoretical analysis and the experimental results that show the potential and applicability of the method.

Equilateral hyperbolic moiré zone plates with variable focus obtained by rotations.

We present equilateral hyperbolic zone plates with variable focal length, which are formed as moiré patterns by a mutual rotation of two identical basic grids. Among others, all principal zone plates, except of the spherical one, can be used as these basic transmittances. Three most important advantages of the proposed moiré zone plates are: a constant aperture of the created element during the mutual movement of basic grids, lack of aberrations due to their undesired mutual lateral displacements and high diffraction efficiency of the binary phase version. To obtain clearer moiré fringe pattern, a radial carrier frequency can be added additionally to the transmittances of basic grids. The destructive interference between both arms of the focal cross of the equilateral hyperbolic moiré zone plate can be obtained by a constant phase shift introduced in the transmittances of the basic grids. Potential applications of discussed elements are indicated, including the most promising one in the three-point alignment technique.