An analysis of the structure and function of the optical designs of the eyes

I then moved to the United States for graduate studies and completed a M. My work, carried out under the mentorship of Dr. John Leigh, primarily examined the interactions between visual-oculomotor and vestibular systems. Michael Mustari from to

An analysis of the structure and function of the optical designs of the eyes

This article has been cited by other articles in PMC. To evaluate wavefront performance and modulation transfer function MTF in the human eye after the implantation of diffractive or refractive multifocal intraocular lenses IOLs.

This was a prospective, interventional, comparative, nonrandomized clinical study. The mean uncorrected distance visual acuity was similar in all three groups of multifocal IOLs.

Cataract surgery, modulation transfer function, multifocal intraocular lenses, wavefront The intraocular light-scattering and higher order aberrations due to refractive or diffractive optics may lead to a poor retinal image quality and undesirable symptoms such as disability glare, halos, and reduction of contrast sensitivity in patients implanted with multifocal intraocular lenses IOLs.

The multifocal diffractive IOL Tecnis ZM, based on the Huygens-Fresnel principle, has a prolate aspheric anterior surface which reduces spherical aberrations. Aberrometers provide an objective measurement of optical aberrations that include sphere, cylinder, and higher order aberrations, such as spherical aberration, coma, trefoil, and other ones.

Wavefront sensors also provide image quality metrics such as the modulation transfer function MTFwhich displays the ratio of image contrast to object contrast for ocular optics as a function of the spatial frequency of a sinusoidal grating.

Materials and Methods This prospective interventional comparative clinical study enrolled eyes of 60 patients subjected to bilateral multifocal IOL implantation.

It should be noted that the surgery occurred on different days with an interval of at least 2 weeks between eyes of the same patient. The study was approved by the institutional review board. Patients were enrolled consecutively in a nonrandomized fashion, as previous studies with multifocal IOLs, based on the clinical judgment of the investigators, to receive either an aspheric multifocal IOL Tecnis ZM 40 eyes; Advanced Medical Optics, Inc.

Instead, the investigator selected the multifocal IOL he or she believed would most accurately meet the individual patient's needs in terms of function and tolerability.

The purpose of this study was not to compare visual acuity and performance in daily activities; instead, the purpose was to compare objective parameters which could represent differences in the optical quality of eyes implanted with different multifocal IOLs with different designs.

Besides that, to minimize the bias of the study we tried to have a higher number of subjects, compared to previous ones. Informed consent was obtained and the study was in adherence to the tenets of the Declaration of Helsinki.

An analysis of the structure and function of the optical designs of the eyes

Patients with a bilateral visually significant cataract with corneal astigmatism lower than 1. Exclusion criteria were any ocular diseases, such as corneal opacities or irregularity, dry eye, amblyopia, anisometropia, glaucoma, retinal abnormality, surgical complications, IOL tilt, IOL decentration greater than 0.

An analysis of the structure and function of the optical designs of the eyes

Patients were examined before surgery and at 1, 7, 30, 90 and days after surgery. At days postoperatively, uncorrected distance 4 mand uncorrected near 0. The visual acuity values were converted to the logarithm of the minimal angle resolution scale logMAR for statistical analysis and then presented in a decimal scale.

All eyes were targeted for emmetropia. Wavefront analysis and modulation transfer function curve were obtained using the iTrace aberrometer Tracey Technologies, Houston, TX, USA which uses ray-tracing technology to obtain wavefront data.

All aberrations were measured up to the sixth Zernike order. The MTF studied refers to distance vision. Measurements were repeated three times to obtain a well-focused aligned image of the eye.

Structure and Function of the Eyes - Eye Disorders - MSD Manual Consumer Version

Measurements were taken for the maximum pupil diameter and then analyzed for 5. Measurements were taken 45 min after the last cyclopentolate drop was instilled. Five millimeters was chosen as the maximum diameter analyzed in order to avoid misinterpretation of the centroids resulting from the size of the capsulorrhexis and the edge of the IOL.Form and Function in the Optical Structure of Bird Eyes 7 (3) the relative and absolute sizes of optical components and (4) the size of pupil aperture.

Photoreceptor structure and function is maintained by a critical tissue, the retinal pigment epithelium (RPE), which recycles photopigments, removes spent outer segments of the photoreceptors, provides an opaque layer to absorb excess light, and performs additional functions.

May 01,  · We have designed, fabricated, and tested a nanoparticle-embedded phantom (NEP) incorporated into a model eye in order to characterize the point spread function (PSF) of retinal optical coherence tomography (OCT) devices in three dimensions under realistic imaging conditions.

Optical illusion is also used in film by the technique of forced perspective. Op art is a style of art that uses optical illusions to create an impression of movement, or hidden images and patterns.

Trompe-l'œil uses realistic imagery to create the optical illusion that depicted objects exist in three dimensions. Designs for optical cloaking with high-order transformations Wenshan Cai, Uday K. Chettiar, Alexander V. Kildishev, and Vladimir M. Shalaev* School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University.

Jul 20,  · The internal structure of the eye includes the following parts: Lens: It is a transparent, biconvex, and an adjustable part of an eye. The lens with the help of the cornea refracts light focused on the retina, therefore creating images on it.

Characterizing the point spread function of retinal OCT devices with a model eye-based phantom