Citation: Mira-Agudelo A, TorresSepúlveda W, Barrera JF, et al. Compensation of presbyopia with the light sword lens. Invest Ophthalmol Vis Sci. 2016;57:6870-6877. DOI: 10.1167/iovs.16-19409 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 (À3 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.Keywords: aging changes, ophthalmic optics, presbyopia, vision acuity, visual optics P resbyopia is the decrease in accommodative amplitude of the human visual system that occurs with aging of the eye. 1Although presbyopia is a progressive vision disorder that affects everyone after a certain age, 2 there is no effective way to prevent it. Therefore, over the last 2 decades, important optical investigations have been undertaken to find ways to compensate for this visual condition.Over time, different optical methods to correct presbyopia and restore the ability to recognize both distant and near objects have been proposed.3-6 Some proposals include reading glasses, monovision, residual myopia, multifocal lenses used in glasses, contact lenses, and intraocular lenses. Multifocal intraocular lenses usually are bifocal or trifocal. 7,8 Recent proposals include modifying the topography of the cornea with refractive surgery 4 or inserting a small-aperture (pinhole) implant to artificially reduce the size of the pupil and generate a wider depth of focus. 9Other possible ways to correct presbyopia include varifocal elements based on the Alvarez lenses 10 or programmable lenses based on spatial light modulators, 11,12 which are classified as accommodative lenses. In addition, adjustable lenses that attempt to mimic how the eye lens functions have been designed, 13,14 and changing the optical power by axial displacement of a lens of a fixed focus has also been implanted and tested. 15,16 Despite multiple proposals and scientific advances, there is still no entirely satisfactory way to correct presbyopia. For some p...

This work presents the first models of light sword intraocular lenses (LS IOLs) with angularly modulated optical power. We performed an experimental, comparative study with multifocal and extended depth of focus intraocular lenses, which are available on the market. The measurements conducted in an original optical bench were utilised for an analysis of point spread functions, elongated foci, modulation transfer functions and the areas defined by them. The LS IOL models perform homogeneous imaging in the whole range of designed defocus. The proposed concept of extended depth of focus seems to be promising for the development of presbyopia-correcting intraocular lenses capable of regaining fully functional vision.

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We propose and evaluate the modifications of a light sword lens (LSL) to obtain better performance for distance vision while maintaining good operation for near and intermediate vision. Methods: The modifications consisted of assigning angular or circular windows for distance vision while rescaling the LSL profile in the remaining area of the element. The objective performance of the redesigned LSLs was verified numerically by the Strehl ratio and experimentally using correlation coefficients and Michelson contrast. Subjective assessments were provided by monocular visual acuity (VA) and contrast sensitivity (CS) through-focus curves for six patients with paralyzed accommodation. The tested object vergence range was [-4.0, 0.0] diopters (D). All experiments were conducted in a custom-made monocular visual simulator. Results: Computational simulations and objective experiments confirmed the better performance of the modified LSL for the imaging of distant objects. The proposed angular and radial modulations resulted in flat VA and CS through-focus curves, indicating more uniform quality of vision with clearly improved distance vision. The VA provided by the modified LSL profiles showed a maximal improvement of 1.5 lines of acuity with respect to the VA provided by the conventional LSL at distance vision. Conclusions: Optimized LSLs provide better imaging of distant objects while maintaining a large depth of focus. This results in comparable and acceptable quality for distance, intermediate, and near vision. Therefore, the modified LSLs appear to be promising presbyopia correctors. Translational Relevance: The new design of LSL reveals an improved performance for all ranges of vision and becomes a promissory element for a real presbyopia correction in clinical applications.

This paper presents an experimental study designed to test the performance of the light sword lens (LSL) with different pupil sizes. To do so, Snellen optotype images obtained by a monofocal lens either with or without an LSL, were compared. Images were obtained for three different pupil sizes at several target vergences. The correlation coefficient and through-focus curves were obtained and compared. The experimental results show differences in the contrast and the depth of focus with different pupil sizes using the monofocal lens without an LSL. In contrast, when using the monofocal lens in combination with the LSL, the quality of the images is similar for all pupils and target vergences used, with slight differences only in halos and contrast. Full Text: PDF ReferencesG. Mikula, Z. Jaroszewicz, A. Kolodziejczyk, K. Petelczyc, M. Sypek, G. P. Agrawal, "Imaging with extended focal depth by means of lenses with radial and angular modulation", Opt Express 15, 9184, (2007). CrossRef A. Kolodziejczyk, S. Bará, Z. Jaroszewicz, M. Sypek, "The Light Sword Optical Element—a New Diffraction Structure with Extended Depth of Focus", J. Mod Opt. 37, 1283, (1990). CrossRef K. Petelczyc et al, "Presbyopia compensation with a light sword optical element of a variable diameter", Photonics Lett. Pol. 1, 55 (2009). DirectLink A. Mira-Agudelo et al, "Compensation of Presbyopia With the Light Sword Lens", Invest Ophthalmol Vis Sci 57, 6871, (2016). CrossRef R.A. Fisher, Statistical Methods for Research Workers (New York, Hafner, 13th Ed., 1958) CrossRef