Compensation of Presbyopia With the Light Sword Lens

Abstract

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...

Presbyopia: Effectiveness of correction strategies

“…Optical methods to increase the depth of focus of lenses could include cubic phase masks to provide an optical transfer function that is virtually insensitive to defocus, allowing the brain to adapt to the image which is equally blurred for different object distances (Arines et al, 2017;Mira-Agudelo et al, 2016). While pinhole inlays hand IOLs have already been commercialised and papers describing pinhole contact lenses exist as early as 1952, where is more recent interest (Garcia-Lazaro et al, 2013;Garcia-Lazaro et al, 2012) and a 2016 completed industry funded clinical trial (ClinicalTrials.gov Identifier: NCT02612584).…”

Optimization of the Light Sword Lens for Presbyopia Correction

“…This modulation is continuous, with different infinitesimal angular sectors contributing linearly to different optical powers. 20,29,30 The phase transmittance function that describes this LSL phase profile is expressed as follows:…”

“…20,28,29 Among these, only LSLs have been studied in subjective experiments or in initial clinical studies for presbyopia compensation. 29,30 An LSL is an asymmetric element with angular variation in the optical power across the complete pupil. To obtain this variation, the element is divided into infinitesimal angular sectors, each with different additions of optical power.…”

“…In a previous study, it was found that LSLs provide satisfactory visual quality in the range of the designed optical power, and their performance declines at the lower and upper ends of this range. 29 It was shown that an LSL designed with the continuous addition of optical power in a range of [0.0, +3.0] D provides appropriate correction for near and intermediate vision (from −2.7 to −0.5 D). However, its performance is not sufficient for both near vision at −3.0 D and distance vision (0.0 D).…”

“…In distance vision, the decline in correction has been quantified as almost 2.0 lines of acuity compared to the distance-corrected naked eye. 29 This issue represents the major drawback of LSLs with respect to other methods for presbyopia correction. For this reason, the issue must be overcome to achieve the actual application of LSLs.…”