Diffractive corneal inlay for presbyopia

Furlan, Walter D.; García-Delpech, S.; Udaondo, Patricia; Remón, Laura; Ferrando, Vicente; Monsoriu, Juan A.

doi:10.1002/jbio.201600320

Cited by 14 publications

(24 citation statements)

References 16 publications

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“…They can be implanted safely with similar outcomes before or after traditional or femtosecond laser-assisted cataract surgery (Ibarz et al, 2017;Stojanovic et al, 2016) and with simultaneous photorefractive keratectomy (PRK) (Moshirfar et al, 2016b). More recently diffractive corneal inlays have been conceived and simulated showing an improved performance compared to the small aperture thin lens corneal inlays (Furlan et al, 2017). Table 3: Current commercially available corneal inlay designs.…”

Section: Inlaysmentioning

confidence: 99%

Presbyopia: Effectiveness of correction strategies

Wolffsohn

Davies

2019

Progress in Retinal and Eye Research

231

178

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Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.

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Section: Inlaysmentioning

confidence: 99%

Presbyopia: Effectiveness of correction strategies

Wolffsohn

Davies

2019

Progress in Retinal and Eye Research

231

178

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“…While this actuating configuration has been presented elsewhere, here we focused on the image quality assessment and the impact on an optical system with aniridia characteristics. Although diffraction effects of the spacer distribution was not covered (area coverage of 3.14%), it is estimated that their effect accounts for less than 5% diffraction, when compared to other studies with similar configurations (KAMRA inlay with 5% diffraction and 8.6% of area coverage) 30,32 . The visual simulations and further assessment are based on the measured contrast of the GH-LCD by means of spectral analysis (1:2.1).…”

Section: Discussionmentioning

confidence: 58%

“…This effect is caused by the intrinsic haze level of the substrate/conductor/GH-LCD and the diffraction of the static spacers, which in turn generate a blurry image. The inherent design of the micro-holes of the small aperture corneal inlays (KAMRA inlay has 8,400 pores of 5-11 μm diameter 28,29 , accounting for an area coverage of 8.6%) produce around 5% of diffraction through the permeable material 30 . However, this intrinsic drawback has recently turned into an advantage by exploiting the photon sieve concept 30,31 .…”

Section: Qualitative Optical Quality and Visible Light Transmittance mentioning

confidence: 99%

Artificial iris performance for smart contact lens vision correction applications

Quintero

Pérez-Merino

Smet

2020

Sci Rep

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This paper presents the simulated performance assessment of an artificial iris embedded on a scleral contact lens using real data from an aniridia patient. The artificial iris is based on guest-host liquid crystal cells (GH-LCD) in order to actively modify the transmittance of the lens and effective pupil size. Experimental validation of the GH-LCD spectrum and iris contrast (determined to be 1:2.1) enabled the development of optical models that include the effect of a small pupil on image quality and visual quality on an optical system with aniridia characteristics. Visual simulations at different light conditions (high/low photopic and mesopic) demonstrated the theoretical capacity of the customized artificial iris smart contact lens to expand the depth-of-focus and decrease the optical aberrations (in particular, the spherical aberration). The visual modelling suggests a maximum depth-of-focus value for a 2-mm pupil diameter for both eyes as follows: 3D (1,000 cd/m 2), 2D (10 cd/m 2) and 0.75D (1 cd/ m 2). This work demonstrates the beneficial optical effects of an active artificial iris, based on visual simulations in response to different light levels, and enables further experimental investigation on patients to validate the dynamic light attenuation and visual performance of smart contact lenses with GH-LCD. A smart contact lens is a device with integrated electronics in direct contact with the eye, which provides sensing, actuation and wireless communication 1,2 and offers both remarkable opportunities and challenges in a wide range of ocular applications: (1) active vision correction 3-8 , (2) biomedical sensing 9-11 and (3) augmented reality 5,12. These applications can be attained thanks to important breakthroughs in miniaturized stretchable systems and hybrid integration of a variety of components onto flexible platforms 13-19. Liquid crystal cells (LC) are particularly attractive as an active electro-optical component 20,21 for presbyopia correction (the age-related loss of the ability to dynamically focus near and far objects) 22,23 or a solution for iris defects (such as aniridia, the partial or complete absence of iris) 8. The artificial iris solution is based on the so-called guest-host liquid crystal (GH-LCD) 24,25. GH-LCD is composed by liquid crystal, chiral dopant and dichroic dye, and is capable of producing transmittance variations when an electric field is applied between its parallel electrodes, due to the combination of chirality and double absorption profiles of the mix 4. The GH-LCD electrodes can be partitioned in independent rings that mimic the functionality of the natural iris when actuated in the correct sequence. Controlled transmittance changes of every ring make the GH-LCD technology an interesting approach to create an active artificial iris embedded within a contact lens; opening extraordinary possibilities in patients with aniridia by attenuating the light intensity through the ocular media and offering new options for presbyopia correction by expanding depth-of-focus with a...

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“…In it, instead of fully transparent zones, micro-holes are made to allow the passage of light and the nutrients, forming a single structure without any substrate. The DCI [21], in addition to presenting the aforementioned micro-hole structure, has a central hole that acts as a pinhole of variable diameter; thus the DCI presents different diffractive orders. The zero order focuses the light for distant vision, while the +1 order forms the near focus.…”

Section: Diffractive Corneal Inlay (Dci)mentioning

confidence: 99%

Diffractive Corneal Inlays: A New Concept for Correction of Presbyopia

Montagud-Martínez¹,

Ferrando²,

García-Delpech³

et al. 2020

Visual Impairment and Blindness - What We Know and What We Have to Know

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A new class of corneal inlays for treatment of presbyopia is described, which uses diffraction as the working principle. The inlay consists of an opaque disk with a small central aperture surrounded by an array of micro-holes that are distributed following the order of a given Fresnel zone plate having N zones. In this way, the central hole of the disk produces an extension of the depth of focus of the eye for distance vision and contributes to the zero order of diffraction, and the light diffracted by the micro-holes in the periphery produces a real focus for near vision. In our general design, the number of zones and the diameter of the central hole are free parameters that can be used to design customized devices with different addition power and near-focus intensity. Two different designs are analyzed to show this property. In the analysis, we employed a ray tracing software to study the performance of the new inlays in the two different model eyes. The results are compared with those obtained with a model of the small-aperture inlay that is currently in the market. The different merit functions used in the comparison and the image simulations performed with the inlays in the model eyes show the excellent performance of our proposal.

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Diffractive corneal inlay for presbyopia

Cited by 14 publications

References 16 publications

Presbyopia: Effectiveness of correction strategies

Presbyopia: Effectiveness of correction strategies

Artificial iris performance for smart contact lens vision correction applications

Diffractive Corneal Inlays: A New Concept for Correction of Presbyopia

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