Imaging properties of the light sword optical element used as a contact lens in a presbyopic eye model

Abstract

The paper analyzes the imaging properties of the light sword optical element (LSOE) applied as a contact lens to the presbyopic human eye. We performed our studies with a human eye model based on the Gullstrand parameterization. In order to quantify the discussion concerning imaging with extended depth of focus, we introduced quantitative parameters characterizing output images of optotypes obtained in numerical simulations. The quality of the images formed by the LSOE were compared with those created by a presbyopic human eye, reading glasses and a quartic inverse axicon. Then we complemented the numerical results by an experiment where a 3D scene was imaged by means of the refractive LSOE correcting an artificial eye based on the Gullstrand model. According to performed simulations and experiments the LSOE exhibits abilities for presbyopia correction in a wide range of functional vision distances.

Assessment of imaging with extended depth-of-field by means of the light sword lens in terms of visual acuity scale

“…In order to assess the characteristics of VA, we used the imaging optical setup (termed the simplified presbyopic eye) inspired by the schematic Gullstrand-Emsley parameterization [21,22] (hereafter referred to as the Gullstrand eye) and presented in our earlier publication [18]. The main assumption of our design was to preserve an image size and depth of field properties of the Gullstrand eye when we replace aqueous and vitreous humors (n = 1.336) with air (n = 1.000).…”

“…A test chart, which the Gullstrand eye should recognize from some distance, must be placed 1.336 times farther. Unlike the setup presented in [18] we used a 3 mm diaphragm (referring to optimal lighting conditions in photopic vision) placed just before the second lens (i.e., the modeling crystalline lens of the Gullstrand eye), therefore rescaling of the pupil diameter was not necessary. We modeled the retina with a 1/3′ CCD array (Sony ICX445 AL/AQ) with 3.75 μm x 3.75 μm pixel size [23] The simplified presbyopic eye is an idealized model of the human eye which simulates only some aspects of the image formed on the retina.…”

“…Numerical simulations and experiments have demonstrated interesting characteristics of the LSOEs in terms of their uniformity, high Strehl ratios [15], and the visual Strehl ratio [16] within the assumed range of defocus. Their imaging properties have also been analyzed by means of the modulation transfer function (MTF) [17] and through the calculation of two parameters showing similarity between the object and its image: namely, a root mean square deviation and a correlation coefficient [18].…”

“…Therefore, fabrication of the LSL represents serious problems and demands. As a result, up to now only two promising, qualitative experiments with LSLs have been presented [13,18]. Such refractive elements were fabricated by the non-uniform exposure of photoresist, but they nevertheless demonstrated distinct aberrations.…”

Effect of spherical aberration in trefoil phase plates on color wavefront coding

“…[5][6][7][8][9][10][11][12][13][14][15][16] Nevertheless, it has been shown that cubic and trefoil-shaped phases are most used to achieve high-quality images when spherical aberration, 10,11) astigmatism 14,15) and high orderaberrations 15) are also present in the system. WFC can be found in many different applications such as in ophthalmic optics, [15][16][17] iris recognition, 18,19) complexity reduction in optical systems, 20) control of thermal defocus in infrared systems, 21) barcode reading, 22) and microscopy, 23) among many others. The DOF in each application can be extended by a trefoil phase at the exit pupil of the optical system, and the trade-off between the DOF and the image resolution properties is dependent on the peak-to-valley value (strength) of the phase.…”