Trade-Off Asymmetric Profile for Extended-Depth-of-Focus Ocular Lens

Lenny A Romero,Andrés G Marrugo,María S Millán

doi:10.3390/photonics9020119

Lenny A Romero, Andrés G Marrugo + Show 1 more

Open Access

https://doi.org/10.3390/photonics9020119

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Abstract

We explore the possibility of extending the depth of focus of an imaging lens with an asymmetric quartic phase-mask, while keeping the aberration within a relatively low level. This can be intended, for instance, for ophthalmic applications, where no further digital processing can take place, relying instead on the patient’s neural adaptation to their own aberrations. We propose a computational optimization method to derive the design-strength factor of the asymmetric profile. The numerical and experimental results are shown. The optical experiment was conducted by means of a modulo-2π phase-only spatial light modulator. The proposed combination of the asymmetric mask and the lens can be implemented in a single refractive element. An exemplary case of an extended-depth-of focus intraocular lens based on the proposed element is described and demonstrated with a numerical experiment.

Highlights

Defocus is one of the most common sources of image degradation in the optical imaging system of the eye
We tested our optimization method with numerical simulations for an imaging system consisting of a diffractive Fresnel lens (FL) combined with an asymmetric phase-mask (APM), which we were able to replicate using a phase-only spatial light modulator (SLM) in our experimental setup
We explored the potential applicability of such results to the design of an extended-depthof-focus (EDOF) intraocular lens (IOL)

Summary

Introduction

Defocus is one of the most common sources of image degradation in the optical imaging system of the eye. An image with maximum lateral resolution is perceived when the human sensor is placed at the optical conjugate plane of the object or, at least, within an axial range of the image space; this is known as depth of focus (DOF). An analogous axial range can be measured in the object space, called depth of field, where objects placed at different distances from the optical system are imaged with maximum sharpness. The DOF can be considered to provide a perceptual tolerance for relatively small focus errors. This perceptual tolerance is certainly desirable, and is common to all physiological feedback control systems [1]. Applications oriented to digital imaging by cameras, and to ophthalmic vision correction, are reviewed in [2]

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