Optimization of the Light Sword Lens for Presbyopia Correction

Abstract

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.

The effects of premium intraocular lenses on presbyopia treatments

“… 71 Another EDOF technique, light sword lenses, is an asymmetric refractive element with angular variation of optical power. 72 Experimental results showed that light sword lenses produced consistently good quality images at a wide range of distances from 25 to 33 ​cm to infinity, and a recent clinical study showed their acceptable VA and high-quality contrast sensitivity at near and distant vision. 73 Overall, all these new EDOF designs represent promising alternatives for presbyopia correction in clinical applications.…”

BCLA CLEAR – Contact lens optics

“…Other designs being explored have unique angular optical elements [97]. One such lens is called the "light sword lens" [98][99][100][101], which is an asymmetric optical element divided into infinitesimal angular sectors, each with different additions of optical power [98]. Another unique design theorised is called the "peacock optical element", which is a particular type of diffractive element capable of focusing light onto segments of arbitrary length, inclination, orientation, and longitudinal intensity distribution [102,103].…”

Smooth multifocal wavefronts with a prescribed mean curvature for visual optics applications

“…Two important ones are the semicircle split bifocal, which includes two commercial models [7], and the triangulate trifocal. To my knowledge, the only pseudo-continuous profile involving both radial and angular profiles is the so-called light sword element [8][9][10][11][12][13][14]. Yet, the light sword lens contains an abrupt discontinuity along a line, although some variants have also been proposed to avoid that discontinuity [11].…”