Retinal image contrast obtained by a model eye with combined correction of chromatic and spherical aberrations

Opto-Mechanical Eye Models, a Review on Human Vision Applications and Perspectives for Use in Industry

The purpose of this review is to aggregate technical information on existent optomechanical eye models (OME) described in the literature, for image quality assessment in different applications. Several physical eye models have been reviewed from peer-reviewed papers and patent applications. A typical eye model includes an artificial cornea, an intraocular lens or other lens to simulate the crystalline lens, an aperture as the pupil, and a posterior retinal surface, which may be connected to a light sensor. The interior of the eye model may be filled with a fluid to better emulate physiological conditions. The main focus of this review is the materials and physical characteristics used and the dimensional aspects of the main components including lenses, apertures, chambers, imaging sensors and filling medium. Various devices are described with their applications and technical details, which are systematically tabulated highlighting their main characteristics and applications. The models presented are detailed and discussed individually, and the features of different models are compared when applicable, highlighting strengths and limitations. In the end there is a brief discussion about the potential use of artificial eye models for industrial applications.

How does the world appear to patients with multifocal intraocular lenses?: a mobile model eye experiment

Background

To show how the world appear to patients with multifocal intraocular lens (IOL) using a novel mobile model eye.

Methods

The mobile model eye was composed of an artificial cornea, IOL, IOL chamber, and a camera. A monofocal IOL (Tecnis monofocal IOL) and two diffractive multifocal IOL (ReSTOR, Tecnis multifocal IOL) were used in the study. We went outside to take a picture of the scenery. At night, we stood on a road and took pictures to see how the traffic lights and headlights of cars looked. For an indoor analysis, we approached the Early Treatment Diabetic Retinopathy Study (ETDRS) chart to the model eye from a distance of 95 cm to check the multifocal function of the lenses. In the car, we took pictures of the street and a cell phone in turn to check the multifocal function of the lenses.

Results

Two multifocal IOLs showed definite multifocal function. Far objects appeared either similarly clear or slightly hazier (depending on the IOL model) than those with the monofocal IOL. In the night vision, there was a mild or severe halo around light sources compared to those with the monofocal IOL.

Conclusion

We believe that this mobile model eye can be used to evaluate how the real world appear to a patient with a multifocal IOL, to explain multifocal function of the IOLs, and possible complications in the patients, before performing a surgery.

Batch Fabrication of Broadband Metallic Planar Microlenses and Their Arrays Combining Nanosphere Self-Assembly with Conventional Photolithography

A novel low-cost, batch-fabrication method combining the spin-coating nanosphere lithography (NSL) with the conventional photolithographic technique is demonstrated to efficiently produce the metallic planar microlenses and their arrays. The developed microlenses are composed of subwavelength nanoholes and can focus light effectively in the entire visible spectrum, with the foci sizes close to the Rayleigh diffraction limit. By changing the spacing and diameter of nanoholes, the focusing efficiency can be tuned. Although the random defects commonly exist during the self-assembly of nanospheres, the main focusing performance, e.g., focal length, depth of focus (DOF), and full-width at half-maximum (FWHM), keeps almost invariable. This research provides a cheap way to realize the integrated nanophotonic devices on the wafer level.

Opto-mechanical design of a dispersive artificial eye

We present an opto-mechanical artificial eye that can be used for examining multi-wavelength ophthalmic instruments. Standard off-the-shelf lenses and a refractive-index-matching fluid were used in the creation of the artificial eye. In addition to dispersive properties, the artificial eye can be used to simulate refractive error. To analyze the artificial eye, a multi-wavelength Hartmann-Shack aberrometer was used to measure the longitudinal chromatic aberration and the possibility of inducing refractive error. Off-axis chromatic aberrations were also analyzed by imaging through the artificial eye at two discrete wavelengths. Possible extensions to the dispersive artificial eye are also discussed.

Achromatic doublet intraocular lens for full aberration correction

A doublet intraocular lens optimized for both chromatic and monochromatic aberration correction in pseudophakic eyes is presented. Ray-tracing techniques were applied to design the lens in white light within a chromatic eye model. Combinations of two materials, already commonly used in intraocular lenses, as acrylic and silicone, were used. Iterative optimization algorithms were employed to correct for longitudinal chromatic aberration, spherical aberration and off-axis aberrations within 10 degrees of visual field. The performance of this lens was compared with a standard single-material aspheric intraocular lens. Near full aberration correction was achieved with the doublet intraocular lens. The modulation transfer function and Strehl ratio were superior for the doublet lens. Through-focus calculations were also conducted showing better optical quality for the doublet. Real higher-order aberrations from normal eyes were incorporated in the model to evaluate the effect on the doublet intraocular lens performance. Results showed that the doublet lens preserved its benefits under realistic conditions. This doublet intraocular lens should provide patients with a better quality of vision after it is further developed in terms of manufacturing and surgical limitations.