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The aim of this study was to investigate whether a different and abnormal corneal profile is present in Down syndrome (DS) by personalized three-dimensional (3D) modelling. This single-centre cross-sectional study included 43 patients with DS (43 eyes) and 58 age-sex-matched control subjects (58 eyes) with normal karyotype and topography. Refraction, central corneal thickness (CCT), aberrations (high-order, coma and spherical), asphericity and morphogeometric/volumetric parameters based on a 3D corneal model that was generated from raw topographical data were evaluated. Deviation of anterior/posterior apex (Dapexant/Dapexpost) and thinnest point (Dmctant/Dmctpost) from corneal vertex, anterior/posterior surface area (Aant/Apost), sagittal area passing through the anterior/posterior apex (Aapexant/Aapexpost) and thinnest point (Amctpost), total corneal volume (Vtotal) and volumetric progression for each 0.05 mm step of the radius value centred to the thinnest point (VOLMCT) and anterior/posterior apex (VOLAAP/VOLPAP) comprised the morphogeometric/volumetric parameters. In the DS group, 58.1% of the eyes presented abnormal topography. High-order and coma aberrations, asphericity, Dapexant, Aant, Apost and Aapexant were significantly higher, whereas CCT, Aapexpost, Amctpost, Vtotal, VOLAAP, VOLPAP and VOLMCT were lower in the DS group than in the control group (p &lt, 0.05). Dapexpost did not differ between the groups (p &gt, 0.05). This study demonstrates that corneas of the subjects with DS are different and more aberrated than those of normal age- and sex-matched non-DS controls. Anterior corneal apex appears to be displaced in DS even with normal topography, while posterior apex seems stable although topography is abnormal. These findings may help to modify our approach in the diagnosis of keratopathy in subjects with DS.

Purpose We propose and evaluate the modifications of a light sword lens (LSL) to obtain better performance for distance vision while maintaining good operation for near and intermediate vision. Methods The modifications consisted of assigning angular or circular windows for distance vision while rescaling the LSL profile in the remaining area of the element. The objective performance of the redesigned LSLs was verified numerically by the Strehl ratio and experimentally using correlation coefficients and Michelson contrast. Subjective assessments were provided by monocular visual acuity (VA) and contrast sensitivity (CS) through-focus curves for six patients with paralyzed accommodation. The tested object vergence range was [-4.0, 0.0] diopters (D). All experiments were conducted in a custom-made monocular visual simulator. Results Computational simulations and objective experiments confirmed the better performance of the modified LSL for the imaging of distant objects. The proposed angular and radial modulations resulted in flat VA and CS through-focus curves, indicating more uniform quality of vision with clearly improved distance vision. The VA provided by the modified LSL profiles showed a maximal improvement of 1.5 lines of acuity with respect to the VA provided by the conventional LSL at distance vision. Conclusions Optimized LSLs provide better imaging of distant objects while maintaining a large depth of focus. This results in comparable and acceptable quality for distance, intermediate, and near vision. Therefore, the modified LSLs appear to be promising presbyopia correctors. Translational relevance The new design of LSL reveals an improved performance for all ranges of vision and becomes a promissory element for a real presbyopia correction in clinical applications.

This study aims to determine whether IntraLase surgery can cause rainbow glare. Monte-Carlo ray tracing method is used to study visual conditions of an ordered microstructure array on the cornea. A corneal flap in the simulated eye model can generate numerous microbubbles caused by IntraLase surgery. Moreover, this study evaluates the visual performance under different conditions such as the size and interval of the microbubble structure on the cornea with vary incident angles and diameters of light. The results of this study can help elucidate the real cause of rainbow glare as a side effect of IntraLase.

There is a need to better understand the peripheral optics of the human eye and their correction. Current eye models have some limitations to accurately predict the wavefront errors for the emmetropic eye over a wide field. The aim here was to develop an anatomically correct optical model of the human eye that closely reproduces the wavefront of an average Caucasian-only emmetropic eye across a wide visual field. Using an optical design program, a schematic eye was constructed based on ocular wavefront measurements of the right eyes of thirty healthy young emmetropic individuals over a wide visual field (from 40° nasal to 40° temporal and up to 20° inferior field). Anatomical parameters, asymmetries, and dispersion properties of the eye’s different optical components were taken into account. A geometry-independent gradient index model was employed to better represent the crystalline lens. The RMS wavefront error, wavefront shapes, dominant Zernike coefficients, nasal-temporal asymmetries, and dispersion properties of the developed schematic eye closely matched the corresponding measured values across the visual field. The developed model can help in the design of wide-field ophthalmic instruments and is useful in the study and simulations of the peripheral optics of the human eye.

Purpose: To quantify on-eye rotational and translational stability of three scleral contact lens stabilization methods and to model the variation in visual acuity when these movements occur in a wavefront-guided correction for highly aberrated eyes. Methods: Three lens stabilization methods were integrated into the posterior periphery of a scleral contact lens designed at the Visual Optics Institute. For comparison, a lens with no stabilization method (rotationally symmetric posterior periphery) was designed. The lenses were manufactured and lens movements were quantified on 8 eyes as the average SD of the observed translations and rotations over 60 min of wear. In addition, the predicted changes in acuity for five eyes with keratoconus wearing a simulated wavefront-guided correction (full correction through the fifth order) were modeled using the measured movements. Results: For each lens design, no significant differences in the translation and rotation were found between left and right eyes, and lenses behaved similarly on all subjects. All three designs with peripheral stability modifications exhibited no statistically significant differences in translation and rotation distributions of lens movement and were statistically more stable than the spherical lens in rotation. When the measured movements were used to simulate variation in visual performance, the 3 lenses with integrated stability methods showed a predicted average loss in acuity from the perfectly aligned condition of approximately 0.06 logMAR (3 letters), compared with the loss of over 0.14 logMAR (7 letters) for the lens with the spherical periphery. Conclusion: All three stabilization methods provided superior stability, as compared with the spherical lens design. Simulations of the optical and visual performance suggest that all three stabilization designs can provide desirable results when used in the delivery of a wavefront-guided correction for a highly aberrated eye.

An understanding of corneal optics is important to optimize the visual outcome after eye surgery. Recent advances in the surgical techniques of lamellar keratoplasty have changed the strategies used for corneal transplantation. Lamellar keratoplasty has the advantage of having a lower rate of graft rejection, superior biomechanical properties, and reduced higher-order aberrations (HOAs) compared with penetrating keratoplasty; thus, the use of lamellar keratoplasty has increased over the last 15 years. However, some patients have poor postoperative visual acuity despite a clear cornea, and the reasons for the poor visual outcome are poorly understood. By combining corneal imaging technologies and the latest optical software, we proposed the concept of "parallelism of anterior and posterior surfaces in lamellar keratoplasty." In physiologically normal eyes, in which the anterior and posterior surfaces are parallel to each other, the posterior surface of the cornea compensates the HOAs of the anterior surface, and this is also true in eyes after penetrating keratoplasty. However, after lamellar keratoplasty, in which the anterior and posterior surfaces are independent and not parallel, irregularities in the posterior surface increase the HOAs of the anterior surface. This article introduces this concept to enhance our understanding of visual optics in eyes after penetrating and lamellar keratoplasties and how to apply this concept to surgery to improve and optimize patient visual outcomes.

Adaptive Optics have become useful tools for basic research in visual psychophysics and neuroscience, in the development of new optical corrections, and in the clinic allowing patients to experience prospective corrections prior to implantation.

A set of methods in terms of both image processing and gaze estimation for accurate eye tracking is proposed. The eye-tracker used in this study relies on the dark-pupil method with up to 12 corneal reflections and offers an unprecedented high resolution imaging of the pupil and the cornea. The potential benefits of a higher number of glints and their optimum arrangement are analyzed considering distinct light sources configurations with 12, 8, 6, 4, and 2 corneal reflections. Moreover, a normalization factor of the pupil-glint vector is proposed for each configuration. There is a tendency for increasing accuracy with the number of glints, especially vertically (0.47 deg for 12 glints configuration versus 0.65 deg for 2 glints configuration). Besides the number of corneal reflections, their arrangement seems to have a stronger effect. A configuration that minimizes the interference of the eyelids with the corneal reflections is desired. Finally, the normalization of the pupil-glint vectors improves the vertical eye tracking accuracy up to 43.2%. In addition, the normalization also limits the need for a higher number of light sources to achieve better spatial accuracy.

Detection of vision defects of a child without professional knowledge is not easy. Very often, the parents of a small child does not know that their child sees incorrect. Also the youngster, not knowing any other way of seeing, does not know that it is not the best. While the vision of a small child is not yet fully formed, it is worth checking them very early. Defects detected early gives opportunity for the correction of anomalies, which might give the effect of the normal development of vision. According to the indications, the American Optometric Association (AOA) control eye examination should be performed between the ages of 6 months to 3 years, before going to school and then every two years. Members of SPIE Student Chapter, in cooperation with the Visual Optics Group working on the Department of Optics and Photonics (Faculty of Fundamental Problems, Wroclaw University of Science and Technology) for 6 years offer selected kindergartens of Wroclaw participation in project “Screening vision tests in pre-school children”. Depending on the number of involved members of the student chapter and willing to cooperate students of Ophthalmology and Optometry, vision screening test was carried out in up to eight kindergartens every year. The basic purpose of screening vision test is to detect visual defects to start the correction so early in life as possible, while increasing the efficiency of the child's visual potential. The surrounding community is in fact more than enough examples of late diagnose vision problems, which resulted in lack of opportunity or treatment failure

Wavefront coding (WFC) enables the depth of field of incoherent optical systems to be extended. This method involves a cubic-phase plate in the system yielding a blurred image nearly invariant to defocus. In visual optics there is a big interest in improving solutions for two different problems: Presbyopia correction and high resolution retinal images with low cost devices. In this work we will show how the use of cubic phases in contact lenses can be an alternative to multifocal lenses and how WFC technique can be applied to record high resolution retinal images reducing the complexity of the actual systems.

The pseudophakic eye lacks the ability to produce a refractive change in response to object proximity. Thus, individual anatomical features such as the pupil size play an important role in achieving functional vision levels. In this work, the range of pupil sizes at varying object distance was measured in pseudophakic participants. Furthermore, the impact of the measured values on eye optical quality was investigated using a computer simulation model. A binocular eye-tracker was used to measure the participants&rsquo, pupil sizes at six object distances, ranging from 0.33 m (i.e., vergence of 3.00 D) to 3.00 m (i.e., vergence of 0.33 D), while observing a Maltese cross with a constant angular size of 1 ∘ . In total, 58 pseudophakic participants were enrolled in this study (age mean &plusmn, standard deviation: 70.5 &plusmn, 11.3 years). The effects of object distance and age on pupil size variation were investigated using linear mixed effects regression models. Age was found to have a small contribution to individual variability. The mean infinite distance pupil size (intercept) was 4.45 ( 95 % CI: 2.74, 6.17) mm and the mean proximal miosis (slope) was &minus, 0.23 ( 95 % CI: &minus, 0.53, 0.08) mm/D. The visual acuity (VA) estimation for a distant object ranged from &minus, 0.1 logMAR (smallest pupil) to 0.04 logMAR (largest pupil) and the near VA ( 0.33 m) when mean proximal miosis was considered ranged from 0.28 logMAR (smallest pupil) to 0.42 logMAR (largest pupil). When mean distance pupil was considered, proximal miosis individual variability produced a variation of 0.04 logMAR for the near object and negligible variation for the distant object. These results support the importance of distance pupil size measurement for the prediction of visual performance in pseudophakia, while suggesting that proximal miosis has a negligible impact in VA variability.

We describe a first-and-second-diffractive-order intraocular lens ((1st,2nd)DIOL) within the class of hybrid refractive-diffractive designs for intraocular lenses (IOLs) and analyse its properties of focus extension and compensation of longitudinal chromatic aberration (LCA), particularly for lenses with low addition. Power, energy efficiency and their wavelength dependence are extended from monofocal IOL and conventional bifocal zeroth-and-first-diffractive-order IOL ((0th,1st)DIOL) to (1st,2nd)DIOL of low addition. Compensation of LCA is experimentally assessed in optical bench through the through-focus energy efficiency of three Tecnis IOLs with red, green and blue illuminations: ZA9003 (monofocal), ZKB00 (bifocal (0th,1st)DIOL with + 2.75 D add) and Symfony ZXR00. We prove Tecnis Symfony ZXR00 IOL can be considered an example of (1st,2nd)DIOL design of low addition, with LCA compensation in both the distance and intermediate foci, whereas the bifocal (0th,1st)DIOL does not compensate in the distance focus. However, the energy efficiency of (1st,2nd)DIOL for wavelengths other than the design wavelength is markedly more asymmetric.

Although there is increasing interest in the investigation of cone reflectance variability, little is understood about its characteristics over long time scales. Cone detection and its automation is now becoming a fundamental step in the assessment and monitoring of the health of the retina and in the understanding of the photoreceptor physiology. In this work we provide an insight into the cone reflectance variability over time scales ranging from minutes to three years on the same eye, and for large areas of the retina (>= 2.0 x 2.0 degrees) at two different retinal eccentricities using a commercial adaptive optics (AO) flood illumination retinal camera. We observed that the difference in reflectance observed in the cones increases with the time separation between the data acquisitions and this may have a negative impact on algorithms attempting to track cones over time. In addition, we determined that displacements of the light source within 0.35 mm of the pupil center, which is the farthest location from the pupil center used by operators of the AO camera to acquire high-quality images of the cone mosaic in clinical studies, does not significantly affect the cone detection and density estimation. (C) 2016 Optical Society of America Research for this work was supported by the Irish Research Council (GOIPG/2013/775), the National Framework Program for Research and Innovation PON (grant n. 01 00110), the Italian Ministry of Health (grant 5×1000) and Fondazione Roma. peer-reviewed

The purpose of this study was to assess repeatability and reliability of a new phoria test as compared to established phoria tests and to assess the possibility of mobile or online testing using the auto-flashed presentation. Near dissociated phoria was measured using the von Graefe method, the Howell card test, the modified Thorington test, and a new dichromatic card test (Red-Blue Phoria card test; RBP card test) on 109 subjects. The inter-examiner difference and test-retest difference were calculated. With the auto-flashed presentation of the RBP card test, near dissociated phoria was measured and the intraclass correlation coefficient and test-retest repeatability was assessed on 26 subjects. The variation in inter-examiner repeatability was the smallest for the modified Thorington test (+3.1/-2.6). The RBP card test was +3.0/-3.1, the Howell card test was +3.5/-2.7, and the von Graefe test was +6.2/-6.0. The variation in test-retest repeatability was the smallest for the RBP card test (+0.4/-1.4). The modified Thorington test was +1.3/-1.3, the Howell card test was +1.27/-1.45, and the von Graefe test was +1.59/-2.20. The ICC was 0.919 for the auto-flashed presentation of the RBP card test. The RBP card test is considered a highly repeatable method clinically and can be made a useful application for testing in mobile or online.

Hartmann–Shack images taken from an archived collection of SureSight refractive measurements of pre-school children in Oxford County, Ontario, Canada were retrieved and re-analyzed. Higher-order aberrations were calculated over the age range of 3 to 6 years. These higher-order aberrations were compared with respect to magnitudes of ametropia. Subjects were classified as emmetropic (range −0.5 to + 0.5D), low hyperopic (+ 0.5 to +2D) and high hyperopic (+2D or more) based upon the resulting spherical equivalent. Higher-order aberrations were found to increase with higher levels of hyperopia (p

This work establishes the average Scheimpflug corneal tomography for a population of 4953 healthy Iranian primary school children. These data were transformed to determine the corneal position and orientation in three-dimensional space, followed by a model fit that combines a biconic with a Zernike expansion. Girls were found to have slightly steeper corneas than boys. Both corneal surfaces show negative conic constants and significant higher-order aspheric Zernike terms. The corneal surfaces are decentered and misaligned with respect to each other and to the line of sight. Consequently, the average corneal surfaces may be considered as decentered and misaligned higher-order aspheres.

We introduce a new method for lens design that combines an eyepiece with the finite model eye, to make a corrected version of the accommodation-dependent Navarro eye. The optical system that we designed, which includes a human eye, takes into account the aberration of the eye and increases the performance of the image in the retina. In the design results, for the optimized eyepiece combined with the corrected Navarro eye, visual acuity is 1.40. Compared with the existing method of eyepiece design using inverse ray tracing with the corrected Navarro eye, MTF value was recorded as 0.079 to 0.283 at 160 lp/mm and visual performance was improved.

Based on optical quality metrics of human eyes,the counterbalanced relationship between defocus and spherical aberration for wave-front aberration data of preoperative and postoperative myopic eyes is studied.The results show that defocus can not obviously compensate spherical aberration for preoperative patients.But the counterbalanced relationship can be distinctly observed for the postoperative patients, which reveals that the remained defocus can partially ameliorate the influence of the increased higher-order aberrations after corneal refractive surgery on visual performance.For postoperative patients,more than 20%improvement of optical quality can be achieved when the remained defocus ranges from 0.27D to 0. 74D.More than 80%of eyes can achieve better visual performance when the remained defocus ranges from 0.3D to 0.75 for a design of vision correction.

In this talk I will review how adaptive optics has been used to improve retinal imaging and visual acuity, and discuss how adaptive optics has influenced other topics in vision science.

Optical coherence tomography (OCT) and reflectance imaging are used in clinical practice to measure the thickness and transverse dimensions of retinal features. The recent trend towards increasing the field of view (FOV) of these devices has led to an increasing significance of the optical aberrations of both the human eye and the device. We report the design, manufacture and application of the first phantom eye that reproduces the off-axis optical characteristics of the human eye, and allows the performance assessment of wide-field ophthalmic devices. We base our design and manufacture on the wide-field schematic eye, [Navarro, R. J. Opt. Soc. Am. A, 1985,2.] as an accurate proxy to the human eye and enable assessment of ophthalmic imaging performance for a [Formula: see text] external FOV. We used multi-material 3D-printed retinal targets to assess imaging performance of the following ophthalmic instruments: the Optos 200Tx, Heidelberg Spectralis, Zeiss FF4 fundus camera and Optos OCT SLO and use the phantom to provide an insight into some of the challenges of wide-field OCT.

We present a system that integrates a double-pass (DP) instrument and a Hartmann-Shack (HS) wavefront sensor to provide information not only on aberrations, but also on the scattering that occurs in the human eye. A binocular open-view design permits evaluations to be made under normal viewing conditions. Furthermore, the system is able to compensate for both the spherical and astigmatic refractive errors that occur during measurements by using devices with configurable optical power. The DP and HS techniques provide comparable data after estimating wavefront slopes with respect to the intersections of an ideal grid and compensating for residual errors caused by the optical defects of the measuring system. Once comparable data is obtained, it is possible to use this combined manner of assessment to provide information on scattering. Measurements in an artificial eye suggest that the characteristics of the ocular fundus may induce deviations of DP with respect to the HS data. These differences were quantified in terms of the modulation transfer function in young, healthy eyes measured in infrared light to demonstrate the potential use of the system in visual optics studies.

The purpose of this study was to evaluate the performance of quartic axicons for presbyopia compensation. The working principle relies on profiting the high depth of focus of the axicons to supplement the reduced accommodation amplitude of presbyopes.We present the design equations of a particular kind of axicon to compensate a general presbyopia condition using simultaneous vision. A rotationally symmetric polynomial of fourth-order, corresponding to the well-known Seidel spherical aberration term, was chosen as its refractive profile. To validate its performance, we computed the retinal images with Stiles-Crawford apodization for a presbyopic eye compensated with this quartic axicon and compared them with those obtained without compensation or with other available solutions based on the simultaneous vision principle.The quartic axicon provides an important improvement of the image quality for intermediate distance vision in comparison with conventional bifocal and trifocal solutions. The image quality, however, is still not optimum for all distances.The results show the usefulness of the proposed approach and point out the need for developing further adapted optimizations.

If it is assumed that the differences between eyes constitute adaptations to different visual environments, then it should be possible to identify the visual environments for which the eye is optimised from these differences. Two different classes of simple eye shapes can be distinguished from the ratio of maximum pupil size to the axial length of an eye. The quantitative description of the two different eye shapes can be used to identify the relative importance of image illumination and resolution to an animal from a cross-section of its eye.

We first investigated the similarity in optical quality of a batch of diffractive intraocular lenses (DIOLs), providing experimental evidence for one DIOL as representative of a batch. Using adaptive optics, we then evaluated one DIOL under different levels of Zernike spherical aberration (SA) by applying both a point spread function test and a psychophysical visual acuity test. We found that for small aperture size SA has the effect of shifting the through-focus curve of DIOL. Also, for a relatively large aperture size, it has different effects on the distant and near foci. (C) The Authors.

We introduce a method to automatically detect drusen in dry age-related macular degeneration (AMD) from optical coherence tomography with minimum need for layer segmentation. The method is based on the en face detection of drusen areas in C-scans at certain distances above the Bruch’s membrane, circumventing the difficult task of pathologic retinal pigment epithelium segmentation. All types of drusen can be detected, including the challenging subretinal drusenoid deposits (pseudodrusen). The high sensitivity and accuracy demonstrated here shows its potential for detection of drusen onset in early AMD.

We first explore the operating principle and optical performances of dioptric-power and astigmatism-variation lens doublets based on the L. W. Alvarez design. These fall within the scope of two ophthalmic applications: ophthalmic glasses for the correction of presbyopia, taking into account any type of ametropia, and spherocylindrical refractors. Second, we present a multiconfiguration optimization method leading to improved optical performances of such doublets over a wide field of view. We then investigate the particular distribution of the curvature on the complex surfaces of the two lenses after optimization.

Ophthalmic materials such as hydrogels and cornea have been micromachined with high repetition rate femtosecond lasers under various conditions. Index of refraction changes are characterized and lateral gradient index lenses are fabricated for vision applications.

© Sociedad Española de óptica. We present in this paper the quantification of the geometrical features of the anterior segment of the eye using Anterior Segment Optical Coherence Tomography (AS-OCT). This quantification was achieved by following our own developed methodology including the device development and their distortion calibration (Fan and refraction) for 3-D imaging, and automatic analysis tools as well. The stastistical comparison of the corrected topographies of the anterior cornea with topographies from state-of-the art clinical topography systems represents a valuable contribution toward the development >All-OCT-based> topographic systems. In addition, we first reported topographies of the crystalline lens in vivo, which is a promising tool to investigate the lens optical properties, the contribution of the lens to the overall retinal image quality, and understanding the change of the physical properties of the lens with accommodation and aging. Furthermore, our quantitative AS-OCT allowed the analysis of the keratoconic cornea and the changes produced by Intra Corneal Ring Segment (ICRS) treatment, as well as monitoring of the ICRS 3-D location. Finally, OCT-based biometry we present in this paper is a promising tool to investigate the changes after cataract surgery; the contribution of the (Intra Ocular Lens) IOL location and tilt to the overall retinal image quality, and in the design of new IOLs., This study has been funded by Spanish Government Grant FIS2008-02065 and FIS2011- 25637 and European Grants EURYI-05-102-ES (EURHORCs-ESF) and European Research Council Grant ERC-2011 AdG-294099 to S. Marcos.

Visual optics is taking on new clinical significance. Given that current refractive procedures can and do induce large amounts of higher order ocular aberration that often affects the patient's daily visual function and quality of life, we can no longer relegate the considerations of ocular aberrations to academic discussions. Instead, we need to move toward minimizing (not increasing) the eye's aberrations at the same time we are correcting the eye's spherical and cylindrical refractive error. These are exciting times in refractive surgery, which need to be tempered by the fact that after all the research, clinical, and marketing dust settles, the level to which we improve the quality of the retinal image will be guided by the trade-off between cost and the improvement in the quality of life that refractive surgery offers.

We demonstrate the possibility of sensing defocus and a combination of defocus and astigmatism aberrations using a digital pyramid wavefront sensor based on a spatial light modulator which allows easy modulation of the pyramid without the need for moving parts.

A digital holographic adaptive optics system for retinal imaging is described. The experimental results on the in vitro retina are reported that demonstrate the feasibility of this imaging mode.

Current developments in cellular resolution in-vivo retinal imaging systems at the UC Davis will be presented. Instrumentation developments include the combination of adaptive optics with optical coherence tomography and scanning laser ophthalmoscopy. © 2011 Optical Society of America.

We present results of numerical analysis of the Strehl ratio characteristics for the light sword optical element (LSOE). For comparison there were analyzed other optical imaging elements proposed for compensation of presbyopia such as the bifocal lens, the trifocal lens, the stenopeic contact lens, and elements with extended depth of focus (EDOF), such as the logarithmic and quartic axicons. The simulations were based on a human eye’s model being a simplified version of the Gullstrand model. The results obtained allow to state that the LSOE exhibits much more uniform characteristics of the Strehl ratio comparing with other known hitherto elements and therefore it could be a promising aid to compensate for the insufficient accommodation range of the human eye. This work was supported by the Polish Ministry of Science and Higher Education under grants N N 514 149038 and N N 518 378237 as well as by the European Social Fund implemented under the Human Capital Operational Programme (POKL), project: “Preparation and Realization of Medical Physics Specialty” with complementary support from the Spanish Ministerio de Ciencia e Innovación (MICINN) grant FIS2008-03884 SI

Adaptive optics allows the simultaneous measurement and manipulation of the eye's aberrations. Some of the recent history, together with my personal views of the future will be covered in the presentation.

A system that records microscopic retinal video while delivering ultra-sharp stimuli to targeted retinal locations is described. The precision of the stimulus presentation to living retina enables an unprecedented level of control for vision research.

(35 Word Limit) A short review of past and present developments of adaptive optics techniques used in Vision Science and ophthalmology for in vivo examination of retina and visual system will be presented.

A general system of noncoaxial separated astigmatic optical elements is examined. Allowance is made for prismatic elements including decentered lenses and refracting surfaces, prisms, and plane interfaces. The directions and positions of a ray entering and emerging from the system are related by a system matrix and a system vector. Given an incident ray one can readily obtain the emergent ray. The analysis is of fundamental importance for visual optics. Two numerical examples are presented. One is a model eye with astigmatic and obliquely crossing astigmatic and decentered surfaces.

Purpose To investigate a set of adaptive optics (AO) imaging biomarkers for the assessment of changes of the cone mosaic spatial arrangement in patients with type 1 diabetes mellitus (DM1). Methods 16 patients with ≥20/20 visual acuity and a diagnosis of DM1 in the past 8 years to 37 years and 20 age-matched healthy volunteers were recruited in this study. Cone density, cone spacing and Voronoi diagrams were calculated on 160x160 μm images of the cone mosaic acquired with an AO flood illumination retinal camera at 1.5 degrees eccentricity from the fovea along all retinal meridians. From the cone spacing measures and Voronoi diagrams, the linear dispersion index (LDi) and the heterogeneity packing index (HPi) were computed respectively. Logistic regression analysis was conducted to discriminate DM1 patients without diabetic retinopathy from controls using the cone metrics as predictors. Results Of the 16 DM1 patients, eight had no signs of diabetic retinopathy (noDR) and eight had mild nonproliferative diabetic retinopathy (NPDR) on fundoscopy. On average, cone density, LDi and HPi values were significantly different (P

The teleost eye, which is commonly used as a model of the typical aquatic eye, is described as having a spherical lens of elevated equivalent refractive index and an accommodative ability involving lens movement toward the retina. The question of lens aberrations, particularly longitudinal spherical aberration, is important because the lens is virtually the only refractive element of an aquatic eye and because the iris is not mobile, at least not in most teleosts. Thus, the typical teleost eye operates at low f-stop levels at all times and peripheral portions of the lens are not masked by the iris. In comparison to the teleost eye, the optical characteristics of the elasmobranch eye have been subject to much less scrutiny. Nevertheless, the data available make it clear that the elasmobranch eye is a much more diverse optical system. First, there are wide variations in lens shape. In some species the lens is spherical or nearly spherical in shape (e.g., Squalus acanthias and Raja eglanteria) while in others the axial diameter of the lens is significantly less than the equatorial one (e.g., Dasyatis sayi and Negaprion brevirostris). Second, the elasmobranch pupil varies extensively in size, shape, and rate of change. The effect of this variation on lens aberrations, particuarly longitudinal spherical aberration, has yet to be evaluated. Third, while the question of elasmobranch accommodation is still obscure, the few studies that have addressed this point indicate that certain species can accommodate and others cannot. To summarize, current confusion concerning the optical characteristics of the elasmobranch eye is due to a diversity which makes generalization difficult. It reflects a more general uncertainty regarding the quality and importance of vision in this group.

Advances in understanding the initial stages of the visual process have been made over the centuries. This heritage will be reviewed with respect to the passage of light through the eye, as well as its gross anatomy and microscopic structure. The links between image formation in the camera and the eye were integrated with the anatomy of the eye in the seventeenth century. They drew attention to the problem of accommodation and to corrections for errors of refraction. Investigations of the structure of the retina were to await the invention of achromatic microscopes in the early nineteenth century. An armory of devices for examining vision and the eye were to follow later in the century. These transformed the study of vision from an observational to an experimental discipline.

This paper presents the results of a comparative computer analysis of monochromatic drawings by mentally healthy subjects and patients with schizophrenia. The contours of the images were distinguished in each of the drawings, after which the following characteristics were calculated: the total length of all the contours of the image, the mean size of the image, and the ratio of the total length of the contours to the mean size. The spatial-frequency spectra of the images were also computed. It is established that the mean size of the drawings and the relative length of the contours in the drawings by the patients with schizophrenia are less than in those of the healthy subjects—i.e., the drawings of the patients with schizophrenia are less detailed. Moreover, these drawings are characterized by a certain rise of the spectrum in the region of medium spatial frequencies. As shown by a computer experiment, on the basis of an analysis of twenty arbitrarily chosen drawings by the patients with schizophrenia, a positive diagnosis can be delivered in 92% of all the cases. When the same sample of drawings by healthy subjects is analyzed, the probability of an incorrect diagnosis was 6.5%. The resulting data are regarded as evidence of dysfunction when there is schizophrenia of the magnocellular system, which provides a global analysis of the images and an increase of the internal noise level of the visual system.

Adaptive optics is becoming increasingly more important in a range of ophthalmic imaging modalities. This talk describes existing wavefront correction and sensing techniques and discusses the exciting developments in microelectromechanical systems (MEMS) and liquid crystals. Such technologies promise improved performance with reduced size and cost.

A method to predict visual acuity in individual eyes has been developed, which combines realistic optical and neural models of early visual processing. Visual acuity is usually obtained as the outcome of a pattern recognition task. However, since the human eye is highly aberrated, standard pattern recognition methods can not be used here, because they fail severely in the presence of optical aberrations, contrarily to what we observe in the human visual system. Here, we have applied a pattern recognition method invariant against optical aberrations, based on early visual models. The results obtained in several real cases provided accurate and realistic predictions of visual acuity. ( Summary only available )

Adaptive optics can compensate for aberrations in the cornea and lens of the living eye, providing a microscopic view of the normal and the diseased retina and a novel tool for measuring the limits of human vision. Recent advances promise to make this technology compact, robust, and affordable.

We discuss optics education within the context of an Optometric professional program leading to a degree of Doctor of Optometry (O.D.). Basic course work in Geometric, Physical, Ophthalmic and Visual Optics will be described and we will discuss how basic optical phenomena can be made relevant to the Optometric student with different academic backgrounds.

Eye designs and visual optics of crustacean eyes are the most diverse of all the major animal groups, as noted by Michael Land in his 1984 review. It is thus appropriate that their spectral mechanisms are similarly varied. Vision in a single crustacean species may include only one spectral photoreceptor class, or it may involve 14 or more different spectral receptor types. Even more impressive, the range of spectral sensitivities of the receptors in the retina of a single crustacean can exceed that of all other species — invertebrates and vertebrates — combined, with sensitivity maxima spanning the spectrum from 315 to nearly 725 nm.