bluuebunny/crossref_metadata_2025 huggingface dataset:
Topographic and Hemodynamic Changes in the Optic Nerve Head in Humans Subsequent to Experimental Modulation of the Intraocular Pressure
Authors: Lovasik John V , Kergoat Hélène , Forcier Pierre , Wojciechowski Robert , Bitton Etty
Published: February 2023

The attrition of nerve fibers in the peripapillary area and the optic nerve head (ONH) in glaucoma has been attributed to mechanical compression of, or aberrant blood flow to the ganglion cell axons comprising the optic nerve1. Recently, greater attention has been focussed on the vascular factors in glaucoma2. Much of the delay in understanding the pathophysiology of glaucoma has been the absence of clinically usable instruments for reliably quantifying subtle structural changes in the ONH, and blood flow in the optic nerve. Fortunately, Petrig and Riva recently demonstrated the applicability of laser doppler principles for measuring blood flow in the ONH in man3, and confocal imaging principles have been adapted for computer reconstruction of serial laser scanned planes of the ophthalmoscopically visible ONH to provide highly accurate and reliable three-dimensional images4 for fundamental/clinical research.
Dynamic Visual Acuity During Vertical Retinal Image Motion: Comparison of Normal and Low Vision
Authors: Demer Joseph L.
Published: February 2023

Telescopic spectacles are potentially advantageous as aids for visually impaired patients, who might be expected to uniformly benefit from optical magnification. However, these relatively costly devices fail to benefit a substantial number of patients with low vision1. Based upon retrospective1 and prospective clinical data2, it has been hypothesized that a major cause of rehabilitation failure with telescopic spectacles is retinal image instability during involuntary head motion. This retinal slip hypothesis supposes that ubiquitous head motion, optically magnified by telescopic spectacles, overwhelms compensatory ocular motor reflexes to produce slipping motion of images on the retina, which degrades dynamic visual acuity (DVA) sufficiently to negate the magnification advantage of the telescopes. Several lines of evidence support this hypothesis. The visual-vestibulo-ocular reflex (VVOR) is the principal compensatory mechanism stabilizing the retina during head movements. The VVOR gain of both normally sighted3 and low vision subjects1 fails to increase sufficiently to match the magnification of telescopic spectacles, a situation presumed to result in retinal image motion during head motion. In normally sighted subjects, actual retinal image motion has been measured during DVA tasks conducted both with vertically moving optotypes, and during vertically imposed head motion4. That study found that, regardless of whether retinal image motion was produced by moving optotypes or moving head, DVA in normal subjects was independent of image velocity up to 2°/sec, but declined with the 0.6 power of image velocity for greater slip. The present investigation was conducted to determine if patients with low vision have a similar relationship between DVA and retinal image slip velocity.
Reading of Dynamically Displayed Text by Low Vision Observers
Authors: Fine Elisabeth M. , Peli Eli , Labianca Angela T.
Published: February 2023

When compared to the time required to read a normally displayed page of text, low vision observers read faster from a scroll display, in which the text is continuously panned across a computer screen (Legge et al., 1989). They also read faster from a rapid serial visual presentation (RSVP) display in which each word is presented to the same place on a computer screen (Rubin & Turano, 1994). The views seen from the scroll display are similar to what would be seen when a magnifier or other low vision aid is scanned across a page of text. Readers with low vision are reported to read text displayed in this manner about 15% faster than a static page of text (Legge et al., 1989). As Legge et al. point out, this advantage may be due, in part, to the time saved because no return sweeps are needed to reposition the eyes at the beginning of the next line of text. This return sweep is time consuming for normally sighted observers (Rayner, 1978), and even more so for low vision observers who are known to have difficulty with eye movement control (cf. Peli, 1986; Whittaker et al., 1991). This advantage for scroll displays was not seen for normally sighted observers in Legge et al.'s study. In fact, they read 44% slower on average.
Stabilized Image Perimetry: Evaluating The Influence of Eye Movements on Perimetry Data
Authors: Fendrich Robert , Wessinger C. Mark , Marshall David , Johnson Chris A.
Published: February 2023

Perimetry is one of the most important diagnostic procedures for monitoring the status of glaucoma and other ocular disorders. A number of studies (e.g., Werner and Drance, 1977; Flammer et. al., 1984) have reported that glaucoma patients and suspects demonstrate greater response variability than normal control subjects. While some investigators (Werner and Drance, 1977; Flammer et. al., 1984) have proposed that this increased variability is due to pathophysiologic changes to optic nerve fibers, other investigators (Henson and Bryce, 1991; Demirel and Vingrys, 1993, 1994; Vingrys and Demirel, 1993) have proposed that the increased variability is due to eye movements interacting with steep gradients in visual field sensitivity. In this view, eye movements act as a low pass spatial filter for steep sensitivity gradients as well as introducing variation in the position of scotoma boundaries, thereby increasing response variability.
Decline in ERG Maximum a-wave and b-wave Amplitudes with Age
Authors: Breton Michael E. , Patel Monica B.
Published: February 2023

Growth in the population over age 60 has increased the clinical importance of diseases of the retina associated with aging. The electroretinogram (ERG), long used as a test of retinal function, has potential for providing important clinical insight for retinal diseases of aging patients. However, interpretation of the ERG is complicated by the well documented, but less well understood, decline in response amplitude as a function of increasing age. Insight into factors leading to ERG amplitude decline with age may be provided by study of receptoral changes, reflected in the a-wave component, compared to changes in inner retinal function, reflected in the b-wave component (Pearlman, 1983). Breton et al (1994) and others (Hood and Birch, 1994) have developed a method of ERG a-wave analysis that yields parameters interpretable in terms of total rod dark current (amax), a constant of transduction amplification (A), and a brief delay associated with cascade molecular interactions (t'eff). This analysis is based on a quantitative model of the G-protein mediated phototransduction cascade proposed by Lamb and Pugh (1992). For purposes of this study, an important feature of the Breton et al (1994) procedure and analysis is the recording of rod response at high stimulus intensities where saturated a-wave and b-wave component amplitudes (amax and bmax) can be effectively measured with minimal algebraic interference with one another (Breton and Montzka, 1992). Based on this approach, changes in ERG amplitudes during development and aging can be used to infer changes in underlying retinal mechanisms. We use this approach to measure maximum a-wave and b-wave amplitudes and receptor transduction response as a function of age in human infants, toddlers and adults from several days up to 80 years.
Disability Glare: Effects of Stimulus Characteristics (Simple Detection, and High and Low Spatial Frequency Contrast Sensitivity) and Temporal Relations between Glare and Stimulus
Authors: Bichao Isabel Cristina , Yager Dean , Meng Jeanette
Published: February 2023

We have previously shown that the effect of a glare source on the detection of simple discs of light depends strongly on the temporal relations between the glare and test sources: thresholds are much higher immediately after the onset of glare and decline to a steady light-adapted level (Figure 1). In addition, these effects are greater when the detection stimulus is in the periphery rather than the fovea (Bichao, Yager, and Meng, 1995; Bichao, Meng, and Yager, 1995).
Effect of Telescopic Spectacles on Retinal Image Stability and Scan Paths During Visual Search by Standing Subjects
Authors: Demer Joseph L. , Viirre Erik S. , Howard D. Troy
Published: February 2023

One obvious limitation of telescopic spectacles (TS) is that they provide magnification at the expense of visual field diameter. Thus, visually impaired people who use TS as visual aids must make head movements to locate targets of interest for scrutiny. When retinal image velocity exceeds 2-3°/sec, visual acuity declines as a log-linear function of this slip velocity1. During unmagnified viewing, the visually-enhanced vestibulo-ocular reflex (VVOR) produces eye movements that compensate for head movements to prevent instability of retinal images of fixed objects. The gain of the VVOR, defined to be the ratio of compensatory eye velocity to head velocity, normally has an ideal value of 1.0 for distant targets. Unfortunately, with TS a simple strategy of making rapid head movements does not necessarily facilitate the efficiency of visual search, since these devices destabilize retinal images by magnifying the relative velocity of the head movements. Ideal VVOR gain with TS would be equal to TS magnification. However, data obtained during passively-imposed and self-generated head rotations suggests that augmentation of VVOR gain by magnified vision is insufficient to attain ideal performance2. Thus, when TS are worn, rapid head movements could degrade visual acuity and lead to target misses.
Off-axis Longitudinal Chromatic Aberration in the Human Eye
Authors: Rynders Maurice C. , Navarro Rafael , Losada M. Angeles
Published: February 2023

Longitudinal chromatic aberration (LCA) of the human eye has been determined by various investigators [1,2] for foveal vision, usually with subjective methods. Due to low peripheral visual acuities, an accurate subjective determination of off-axis LCA is not possible at large eccentricities. Consequently, no data are available today on the ocular LCA beyond a few degrees away from the fovea. Charman and Jennings [3] determined the foveal LCA objectively using a double pass technique for one observer. They found a basic agreement with subjective data, finding only minor discrepancies between the subjectively determined best focus and the objective best focus criterion (smallest line width at half height). Their objective values were less myopic than subjective data for the shorter wavelengths. In the present study, we measure LCA throughout the visual field also using a double pass method [4]. In addition we have tested for possible discrepancies between objective and subjective data (as reported by Charman and Jennings [3]) for different wavelengths and for eccentricities of 0° and 2.5°, studying possible implications for the suitability of the double pass technique in determining LCA objectively. This objective versus subjective comparison has been done by the method of William's et al. [5] where the focusing target is a purely monochromatic point source.
Changes in Focal Length and Spherical Aberration of the Human Crystalline Lens with Ageing
Authors: Glasser Adrian , Campbell Melanie C.W.
Published: February 2023

The human lens undergoes many changes during ageing that compromise vision. Many of these changes are relatively poorly characterized due to the difficulties of measuring optical properties of the human lens in vivo. We have undertaken a study of human eye bank eyes to better understand some of the effects of aging on the human lens which may help to understand presbyopia and the lens paradox. The lens continues to grow throughout life resulting in an increase in axial thickness1 and increased curvatures2. This would be expected to result in an increasing lens power that, without compensatory changes in the eye, would cause a myopic shift with ageing. However, presbyopia results in exactly the opposite effect, namely a loss of near vision. Changes in the refractive index distribution in the lens have been suggested to account for this ‘lens paradox’3,4. Previous studies have attempted to model changes in the refractive index distribution with ageing, but these models are in part based on assumptions that have not been verified for the human lens. In addition, in order to completely understand how the lens contributes to visual function in the eye it is necessary to consider the interaction of the lens optics with the cornea and the comeal-lens separation.
Retinal Laser Spot Size with Wavelength
Authors: Rockwell Benjamin A. , Stolarski David , Thomas Robert J.
Published: February 2023

National laser safety standards are based on minimal visual lesion threshold (MVL) studies in different animal models. The energy required for a retinal lesion depends upon many parameters including wavelength and retinal spot size. We attempt to explain trends in reported minimum visible lesion threshold studies using a model which represents every layer of the eye. There currently exists a lack of minimum visible lesion data in the near-infrared region of the electro-magnetic spectrum. To address these deficiencies, we extend our calculations into this wavelength regime to predict expected trends.
Development of Image Psychophysics Software and Calibrator for Macintosh Systems
Authors: Tyler Christopher W. , McBride Brennan
Published: February 2023

The core function of noninvasive psychophysical testing is the measurement of contrast sensitivity for spatial patterns specified with some mathematical luminance profile and a controlled time course. Desk-top computers would appear to be ideally suited for such a task and yet most of the software for such computers requires special-purpose hardware modifications and software that requires programming to achieve the desired experimental configuration. In particular, there seems to be no convenient software that take advantage of the graphics sophistication of the Macintosh computer.
The Effects of Radial Keratotomy on the Asphericity of the Cornea
Authors: Schwiegerling Jim , Greivenkamp John E. , Miller Joseph M. , Snyder Robert W. , Palmer Millicent L.
Published: February 2023

Radial Keratotomy (RK) causes at least three different changes in the shape of the corneal surface. Each change alters the optical properties of the surface. The first alteration is a flattening in the base curvature of the eye, which modifies the overall optical power of the eye. A second more subtle change is in the asphericity of the cornea. The asphericity of the cornea does not affect the overall power of the eye, but influences visual performance by controlling the amount of spherical aberration in the eye. Finally, there are higher-order variations in the corneal surface resulting from the RK incision pattern, which can cause a more complex change in visual performance.
Evaluating the PAR Corneal Topography System: A Preliminary Study
Authors: Munger Rejean , Casson Evanne J. , Jackson W. Bruce
Published: February 2023

In the last decade a number of new technologies have been developed that allow us to alter the shape of the cornea. The ultimate goal of these technique is to be able to reshape the corneal surface reliably and accurately and thus permanently correct most types of refractive errors and provide patients with optimum visual performance without corrective lenses. One of the barriers that has impeded the progress of these techniques has been the lack of a reliable and accurate description of the corneal surface before and after the reshaping of the cornea. Only with this knowledge can we begin correlating the optical properties of the cornea and the change in visual performance resulting from the surgery.
Time Series Analysis of PRL Movement during Fixation
Authors: Schuchard Ronald A. , Cooper Shawn , Lakshminarayanan Vasudevan
Published: February 2023

Previous studies of eccentric PRLs (preferred retinal loci) due to central scotoma have documented that the PRLs for fixation are significantly larger than foveal PRLs for fixation (e.g., (Schuchard and Raasch, 1992; Fletcher and Schuchard, 1995)). The fixation target can be found within a 9 degree or smaller retinal area for eccentric PRLs while foveal PRLs (i.e., normally functioning foveas) usually keep the fixation target within a 2 degree or smaller retinal area. These previous investigations of PRLs for fixation have studied the two dimensional spatial characteristics of monocular PRLs but not the dynamic temporal/spatial characteristics of the PRL during fixation. Therefore, it is not known whether the increased PRL size is due to larger drifts and/or microsaccades during fixation (although from this point on we will refer to the microsaccades as jerks since these small jumps can be quite large for some subjects).
MNREAD Acuity Test Reliability in Patients with Age-Related Maculopathy
Authors: Bane Mark C. , Fish Gary E. , Spencer Rand , Moushegian Susan E.
Published: February 2023

The recently developed MNREAD ACUITY CHARTSR have been suggested to be very useful tools for clinical examination and research in patients with low vision1. The MNREAD charts were designed to address limitations found with standard near optotype acuity tests. The design of many standard near acuity tests is not consistent with currently accepted acuity chart guidelines2, and it has been found that standard optotype acuities are poor predictors of reading performance3 and the ability to use low vision aids4. A potential advantage of the MNREAD charts is that they can be used to quantify reading speed across a range of sentence character sizes in patients with low vision. Previous studies have found that MNREAD measures of reading acuity, optimal character size and critical character size are very useful indices for characterizing reading abilities in patients with low vision1,5-6. However, the MNREAD charts are relatively new, and little is known about the test-retest reliability of MNREAD measures in patients with low vision.
Multi-focal electroretinography in diabetic retinopathy
Authors: Palmowski Anja M. , Bearse Marcus A. , Sutter Erich E.
Published: February 2023

Diabetes mellitus (Dm) is a major cause of visual loss5 which may be prevented by good blood sugar control as well as timely retinal laser-photocoagulation. The mechanism of action of photocoagulation is not entirely clear yet. However destroying ischemic retinal areas is thought to reduce the production of angiogenic factors and thereby reduce neovascularizations and their complications. One problem is that the optimal time to induce laser treatment is often well before the diabetic patient is symptomatically affected. Even slitlamp examination does not always show signs of early retinopathy. Avascular retinal areas that may only be seen in fluorescein-angiography signify a 'point of no return' in the course of diabetic retinopathy6.
Computation of the Modulation Transfer Function (MTF) for Progressive Addition Lenses (PAL's) and Its Applications
Authors: Baumbach Peter , Dorsch Rainer G.
Published: February 2023

For the examination of a patient’s visual characteristics, astigmatism and mean power errors or visual acuity (V. A.) are basic optometric quantities. Unfortunately those quantities do not incorporate the pupil diameter as a variable but rather for an average fixed size. Moreover V. A. is measured for spherical and cylindrical trial lenses only. For PAL’s the pupil diameter is important because of the gradient behaviour of astigmatism and mean power. In this paper we introduce a new quantity which incoperates the pupil size. This quantity, which we call relative optical performance (R. O. P.), is based on the modulation transfer function (MTF) that takes a finite aperture into account.
Accommodative and Orientational Demands through Optical Systems in General
Authors: Harris W F
Published: February 2023

A point object in space imposes on an eye accommodative and orientational demands that depend on the optical structure of the intervening space. The intervening space may contain a thick, decentered, astigmatic spectacle or contact lens, underwater goggles and water, a telescope, or a microscope, for example. The demands define the accommodation and the turn the eye needs to execute for satisfactory observation of the object. The purpose of this paper is to provide a general first-order method for determining them.
Caustics in Astigmatic Optical Systems
Authors: Campbell Charles
Published: February 2023

Caustics in the optical systems are created when, among other things, spherical aberration is present. When astigmatism is also present several new interesting effects are introduced. Using a ray vector field formalism, a treatment of the combined effects of the spherical aberration and astigmatism is given. The double caustic lines which have been shown to cause monocular diplopia are found and their character quantified.
Method To Estimate The Ocular Wavefront Aberration From A Pair Of Double Pass Retinal Images
Authors: Iglesias Ignacio , Artal Pablo
Published: February 2023

The amount of Seidel aberrations, point spread and optical transfer functions can be computed from the wavefront aberration. In the case of the eye, the wave aberration is a complete descriptor of the ocular optics and a useful function in ophthalmic and intraocular lenses design. The possible use of adaptive optics techniques in the eye is also increasing the current interest in detecting the ocular wave aberration. Different methods have been previously used to determine the ocular wave aberration (see reference 1 for a review); among others the aberroscope (2), the Hartmann-Shack sensor (3) or computations from retinal images (4).
Topography and optical performance of the cornea following hyperopic Excimer PRK
Authors: Munger Rejean , Casson Evanne J. , Jackson W. Bruce
Published: February 2023

Visual performance after refractive surgery depends critically on the optical quality of the post-operative cornea. To understand subtle visual problems that cannot be corrected by optical means we must go beyond the paraxial refractive power of the cornea and fully characterize its optical properties. Research is also required into the relationship between the shape of the cornea and visual performance after PRK. As a first step towards a better description of the optical characteristics of PRK corneas we are developing ray tracing methods, which use corneal topography as the surface descriptor, to calculate their optical properties. The Eye Institute is also involved in a pilot study to evaluate the VISX “STAR” Excimer laser for PRK treatment of hyperopia. In this paper we present data on (a) corneal optical quality, (b) corneal topography (ablation profile), and (C) visual acuities for 2 patients followed for 6 months after a hyperopic Excimer PRK surgery.
Three-dimensional reconstruction of surfaces by automated infrared photoretinoscopy
Authors: Schaeffel Frank , Weiss Stefan , Howland Howard C.
Published: February 2023

A photoretinoscope with infrared light-emitting diodes (LED) operating simultaneously from different eccentricities creates an almost linear change in brightness across the pupillary meridian perpendicular to the knife edge (Schaeffel et al., 1993a). The slope of the brightness profile, in turn, is almost linearly related to refractive error over a range of +5 to -5D. Using digitized video images, the procedures to find the pupil and to measure the slope can be fully automated and run at 25/30Hz (Schaeffel et al., 1993b). The precision of detection of differences in refraction are comparable to the depth of focus of the eye (0.25 D).
The Effect of Entrance Beam Location within the Pupil on Image Quality of CSLO Images
Authors: Muth Kerstin , Campbell Melanie C. W. , Roorda Austin J. , Cui Chengwu
Published: February 2023

The confocal scanning laser ophthalmoscope (CSLO) is currently used both in clinical and research settings. Generally the patient or subject is positioned so that the laser beam travels approximately through the centre of the pupil.
Rapid Derivation of the Stiles-Crawford Function Using Electrophysiological Responses
Authors: Sutter Erich E.
Published: February 2023

Since its discovery1, the Stiles-Crawford effect has been extensively investigated by means of psychophysical techniques2. Studies were motivated in part by possible application of the effect for the assessment of receptor function in patients. However, as yet, relatively little is known concerning changes of the Stiles-Crawford function in retinal pathology. This may be due to the fact that the psychophysical measurements are time consuming for the operator and demanding on the patient.
Do the cones see light scattered from the deeper retinal layers?
Authors: Burns Stephen A. , He Ji Chang , Delori Francois
Published: February 2023

The inside of the eye has the potential to act as an integrating sphere, since once in the eye there is little opportunity for light to exit the eye. This tendency is canceled over much of the spectrum by the presence of pigments, especially melanin, which absorb light and decrease the effective path length of light inside the eye. However, since long wavelengths of light penetrate more deeply into the retina and choroid (Norren and Tiemeyer; 1986, Delori and Pflibsen 1989, Eisner et al.;1996), being absorbed to a lesser extent by melanin, blood and other ocular pigments, there is a potential for the contrast of images to be decreased by scattering of light in the RPE and choroid. In patients this is more likely, since in many retinal diseases there are marked changes in the melanin content and distribution and, as a result, potentially increased scattering. One factor that is believed to decrease the sensitivity of the eye to stray light is the alignment of the cones such that their long axis points toward the center of the pupil (Laties and Enoch; 1971). Since the cones act as waveguides, aiming the cones towards the pupil should increase their sensitivity to light entering the eye from the pupil, and decrease sensitivity to light illuminating them from the sides. In addition, the cones are tapered, with the inner segments (where the presumed optical aperture resides) being larger than the outer segments. This tapering may also decrease the sensitivity of the cones to light illuminating them from behind. In the current paper we test this idea by “generating” a light which illuminates the retina from behind and measuring whether this light is guided by the cones back towards the pupil.
Limits to vertical fusion in the field of vision
Authors: Hernandez-Castañeda Martha , Pédrono Claude , Miège Christian
Published: February 2023

Fusion is the property that allows the perception of a single image in a single binocular direction. Fusion is made up of two components: motor fusion in which vergence eye movements compensate for disparate retinal images, and sensory fusion, which is the property of the visual system that allows the perception of a single objet to be obtain from disparate images without using vergence eye movements.
Functional Analysis of myopias without central retinal degeneration
Authors: de Mattiello M.L.F. , Maneiro M. , Buglione S.
Published: February 2023

Recent publications 1 admit that “the myopic indexes in the industrial nations have increased and range from 20% to 80% in the U.S. and Europe, to up to 90% in the Far Eastern countries, depending on the age group and the professional population considered”. This increase has again arisen attention on this illness that may be corrected with optical aids and more recently with refractive surgery. In clinical practice, evaluation of myopia or its recovery is mainly, if not exclusively, made with the traditional visual acuity tests. Contrast tests are applied in some cases. However, the literature reports other functional disorders such as considerable variations in the accommodation ranges, chromatic vision defects, specially in colors of short wave lengths2 and alterations in adaptation to darkness3.
Video-based eye tracker: A clinical tool in assessing binocular vision?
Authors: Irving EL , Goltz HC , Steinbach MJ
Published: February 2023

The electro-oculogram (EOG) historically has been the most common clinically-used objective eye movement recording device. EOG is based upon the corneo-retinal potential difference1 and has many limitations2-4. More recently photoelectric techniques have been used to objectively record eye-movements. These instruments also have a limited linear range2. Eye movements can be recorded accurately using a magnetic search coil5, but this requires that a contact lens annulus containing the coil be placed on the patient's eye. The procedure tends to be time-consuming and is not well tolerated by a significant number of patients. Video technology has lead to a new generation of user and patient-friendly, non-invasive eye tracking devices. One such instrument, the El-Mar 2020 (Downsview, Ontario) eye-tracker, calculates eye rotation from the differences between the corneal reflections and the center of the pupil. This makes head stabilization unnecessary for accurate tracking, as it eliminates artifacts caused by lateral motion of the camera with respect to the head. These translation artifacts can be quite large (1 mm = 5 degrees for pupil tracking only, 1 mm = 10 degrees for corneal reflection tracking only). The system is free from drift, has a maximum resolution of 6 minutes of arc, a 120Hz sampling rate and a linear range of +/-40 and +/-30 degrees in the horizontal and vertical meridia respectively6. The instrument has been compared favorably to the magnetic search coil for oculomotor testing in humans6.
The SKILL Card in the Optic Neuritis Treatment Trial
Authors: Schneck M E , Haegerstrom-Portnoy G , Brabyn J , Katz B
Published: February 2023

Optic neuritis is an acute, inflammatory disease of the optic nerve that is usually accompanied by ocular pain, affects more women than men, and may be associated with multiple sclerosis1. A broad range of visual functions are typically affected. The severity of the visual loss varies from a slight visual field deficit to no light perception. Even when acuity returns to normal, as it generally does over the course of weeks or months, visual function frequently remains abnormal2,3. A common complaint of optic neuritis patients is trouble seeing under reduced illumination conditions, such as driving in a tunnel.
Reading with Half a Visual Field
Authors: Fine Elisabeth M. , Vessel Edward A. , Rubin Gary S.
Published: February 2023

Several recent reports (e.g. Guez et al., 1993; Schuchard, & Fletcher, 1994) have indicated that most patients with central scotoma develop a preferred retinal locus (PRL) adjacent and to the left of their scotoma in visual field space. Guez et al. suggested that this might be beneficial for reading because knowing where the eye has been would help guide the readers eye movements. However, this situation eliminates the possibility of gathering information from the letters to the right of fixation (because of the scotoma), which Rayner and his colleagues (e.g. 1980, 1982) have shown to be critical to reading. This implies that a PRL to the right of the scotoma border would be more beneficial to the reader because she would be able to gather information from the upcoming text, not the text that has already been deciphered.
Can cone directionality improve retinal image quality?
Authors: Bums Stephen A. , He Ji Chang , Marcos Susana , Webb Robert H.
Published: February 2023

The cone photoreceptors of the human eye actively orient towards the
pupil of the eye.
The Spatial Distribution of Human Macular Pigment
Authors: Bieber Michelle L. , Werner John S.
Published: February 2023

Fundus photography, entoptic visualization and psychophysical evidence all indicate that the peak density of the macular pigment (MP) is in the fovea and it decreases in density with increasing retinal eccentricity.
Contrast Dependence of Multifocal ERG Components
Authors: Bearse Marcus A. , Sutter Erich E.
Published: February 2023

Multifocal techniques 1 are becoming more widely used to record the electroretinogram (ERG) in both research and clinical applications.
Predicting Closed Road Sign Recognition Performance from Vision Tests
Authors: Higgins Kent E. , Wood Joanne
Published: February 2023

One of the ongoing issues confronting motor vehicle licensing agencies concerns the selection of a vision test battery that will enable prediction of visually-dependent aspects of driving performance.
Relationship Between Performance of Tasks of Daily Living and Tests of Visual Function in Patients with Retinitis Pigmentosa
Authors: Szlyk Janet P. , Fishman Gerald A. , Alexander Kenneth R. , Laderman Denice J. , Ho Kong , Seiple William
Published: February 2023

It is of interest to determine how patients’ performance on clinical tests relates to their ability to conduct tasks of daily life.
Three-Dimensional Analysis of Corneal Image Forming Properties: A Monocular Diplopia Example
Authors: van de Pol Corina , Tran Henry H. , Garcia Dan D. , Klein Stanley A.
Published: February 2023

Corneal topography methods of representing the image-forming properties of the cornea include, but are not limited to, refractive error, wavefront error and irregularity mapping.
Enhancement of letter recognition by explicit and implicit cueing of transient focal attention
Authors: MacKeben Manfred
Published: February 2023

The intensity of a visual percept is controlled by physical stimulus variables like size, contrast and duration. In addition, there are internal conditions that influence the percept, like expectation, previous percepts (masking), or whether the stimulus is attended or unattended. This study shows that attending to the future target location in visual space can boost perception more than an equivalent lengthening of the target duration.
Stimulus Motion Influences Measured Visual Field Extent in Toddlers
Authors: Dobson Velma , Delaney Suzanne M. , Weidenbacher Hollis J. , Harvey Erin M. , Leber Natalee
Published: February 2023

Studies of visual field development between birth and age 7 months have been conducted using a variety of stimuli, including three-dimensional objects, flickering lights, and moving gratings, and a variety of procedures, including kinetic perimetry (KP), static perimetry (SP), and a combination of KP and SP, termed hybrid static-kinetic perimetry (HP) (see Maurer & Lewis, 1991; Mayer & Fulton, 1993, for reviews). In contrast, little information is available on the effects of stimulus parameters or procedural variations on measured visual field extent in children between I and 3 years of age. Stimuli used in visual field studies of children in this age range have been almost exclusively 6-deg white spheres, presented using WSKP, a KP procedure in which the white sphere is attached to a wand and moved by hand along the arms of an arc perimeter (Mohn & van Hof-van Duin, 1986).
Changes in Amacrine Cell Numbers and Morphology in Response To Induced Myopia and Hyperopia
Authors: Wong S.T. , Sivak J.G. , Bal A.K. , Callender M.G. , Bakelaar A.J.
Published: February 2023

Myopia and hyperopia have been artificially induced in animal models by
various manipulations of their early visual environment. Ametropias
have been produced using lid suture1, changing illumination levels
(dark-rearing2, constant light3, dim lighting4), intra-ocular
injections5, treatment with defocussing lenses6, and the application
of translucent occluders7. Abnormal ocular growth appears to be a
major factor that causes ametropia. Myopic eyes are enlarged, while
hyperopic eyes are smaller compared to control eyes. Changes in the
sclera8, choroid9, and orbital bone10 surrounding the affected eyes
also reflect abnormal growth mechanisms. Various studies11,12,13
suggest that the signal or signals which control eye growth may arise
from within the retina itself. It has been suggested that retinal
amacrine cells play a role in mediating ocular growth8. This study
examines how dopaminergic and serotonergic amacrine cells are
quantitatively and qualitatively affected by induced myopia and
hyperopia.
Quantum Lithography and Microscopy
Authors: Zubairy M. Suhail
Published: February 2023

We discuss two related problems: qauntum lithography with classical light and the precision measurement of small separations between two atoms or molecules placed in a standing wave laser field.
Entanglement purification by natural spin-spin interactions and single spin measurements
Authors: Maruyama Koji , Nori Franco
Published: February 2023

We present a simple protocol to purify bipartite entanglement in spin-1/2 particles by utilizing only natural spin-spin interactions and S
z
-measurements on single spins. It is shown that only one switching on (and off) of a multi-spin interaction, as well as single spin operations, is sufficient for purify entanglement. This approach significantly reduces the number of controls that would induce errors compared with conventional purification protocols and it could be useful for quantum information processing in solid-state-based systems.
Disentanglement of Atoms in Relativistic Motion
Authors: Lin Shih-Yuin
Published: February 2023

We calculate the exact evolution of the entanglement between an inertial oscillator (Alice) and a uniformly accelerated one (Rob), both coupled with the same scalar field. The finite disentanglement-time is observed and the Unruh effect in this system is studied.
Is Quantum Information Relevant to Particle Physics?
Authors: Shi Yu
Published: February 2023

Quantum Information has been discussed in almost all areas of physics reigned by quantum mechanics, except particle physics. Here I demonstrate that quantum information as a fundamental concept can be extended to the regime of particle physics and relativistic quantum field theory. I shall describe a scheme of quantum teleportation and entanglement swapping in terms of neutral kaons. In this scheme, the kaon whose state is to be teleported collides with one of the two entangled kaons in an Einstein-Podolsky-Rosen state. Subsequent detection of the outgoing particles of the collision completes the two-qubit projection on Alice side. In this scheme, notions of quantum information science naturally connect with conservation laws of particle physics. I will also explain basic ideas on how to define quantum entanglement in the setting of relativistic quantum field theory.
Entanglement in quantum many-body systems far away from thermodynamic equilibrium
Authors: Briegel Hans
Published: February 2023

We show that quantum mechanical entanglement can prevail even in noisy open quantum many-body systems at high temperature and far away from thermodynamical equilibrium, despite the deteriorating effect of decoherence. The system consists of a number N of interacting quantum particles, and it can interact and exchange particles with some environment. The effect of decoherence is counteracted by a simple mechanism, where system particles are randomly reset to some standard initial state, e.g. by replacing them with particles from the environment.
Entanglement of two qubits near plasmonic band gap
Authors: AI-Amri M.
Published: February 2023

We study the quantum entanglement of a two-qubit system interacting with single-frequency plasmonic excitations. Under the exact resonance condition and in the presence of both the Stark shift and phase shift, an exact solution of the time evolution of the unitary operator is obtained. Employing this solution an analytical expression for time evolution of the negative eigenvalues for the partial transposition of the density operator is obtained. Numerical investigations are carried out for the entanglement with different values of Stark shift and plasmonic excitations. It is shown that, the entanglement is affected by the plasmonic excitation and the Stark shift.
‘Quantum Nonlocality without Entanglement’ in a Pair of Qubits
Authors: Koashi Masato , Takenaga Fumitaka , Yamamoto Takashi , Imoto Nobuyuki
Published: February 2023

We consider unambiguous discrimination between separable bipartite states, one being pure and the other being a rank-2 mixed state. We show that the optimal success probability achieved by separable measurements is never achieved under LOCC.
Holey Fibers with a Limited Number of Air Hole Rings in the Cladding: Design, Fabrication and Application for Some Interferometric Sensing Devices
Authors: Minkovich Vladimir P.
Published: February 2023

Large-mode-area all-silica holey fibers (HFs), which are specially designed with a limited number of air hole rings in cladding, are presented. Fibers with 2, 3, and 4 air hole rings were inspected, and the transmission losses and the demands for the single-mode waveguide operation in a series of the HF samples with different relative hole diameters d/Λ were analyzed. It has been found, in particular, that for the fibers there is an optimal ratio, d/ Λ =0.52±0.05, that provides a single-mode output for shorter HFs (a few meters long), and low transmission and bending losses for longer HFs (hundreds of meters long). The HFs developed were used for the fabrication of compact modal interferometers, which represent special tapers with gradually collapsed air holes in the taper waist. The gradual collapsing of the holes is achieved by tapering the fibers with a “slow-and-hof ’ method (nonadiabatic process). As a result, at the excitation of the fundamental mode in the HF core, it couples to two high-order modes of the solid taper waist. Due to the beating between the modes, the transmission spectra of the taper exhibit several interference peaks that are shifted to a shorter or longer wavelength under the influence of various external parameters. The use of the HF tapers in different sensing devices for the measuring of refractive indexes of liquids, high temperature, strain, and hydrogen sensing is demonstrated.
CW Supercontinuum Generation in Photonic Crystal Fibres with Two Zero-Dispersion Wavelengths
Authors: Kudlinski A. , Cumberland B. A. , Travers J. C. , Bouwmans G. , Quiquempois Y. , Mussot A.
Published: February 2023

This study is devoted to supercontinuum generation in photonic crystal fibres using a continuous-wave pumping scheme. We demonstrate that the spectral broadening of a continuous-wave laser can be more efficiently achieved in a short piece of photonic crystal fibre with two zero-dispersion wavelengths rather than in a fibre with a single one. This is due to efficient self-frequency shift of the solitons initially created by modulation instability, because their peak power is kept high in fibres with two zero-dispersion wavelengths. We then focus on the dynamics of the supercontinuum evolution under continuous-wave pumping in a series of different photonic crystal fibres exhibiting two zero-dispersion wavelengths. Control of the supercontinuum spectral extension is demonstrated as well as the changing dynamics as the zero-dispersion wavelengths are brought closer together. For closest zero-dispersion wavelengths, the spectral broadening is mainly due to parametric processes. For increasing spectral separation between the two zero-dispersion wavelengths, the soliton self-frequency shift due to intrapulse Raman scattering becomes more important. The soliton self-frequency shift is canceled just before the second zero-dispersion wavelength and some energy is transferred to a phase-matched dispersive wave. We also pay particular attention to the effect of the water absorption band located around 1380 nm.
Beyond Efficient Generation of Multiple Four-wave Mixing Products
Authors: S. Arismar Cerqueira
Published: February 2023

A highly efficient technique to generate broadband cascaded four-wave mixing (FWM) products is proposed. It consists of launching two or three strong pump waves near the zero-dispersion wavelength of very short (of order of few meters) optical fibers. Depending on the application, the fiber dispersion and nonlinear properties, as well as the pump wavelengths should be properly chosen in order to obtain the required bandwidth, uniformity and separation of the frequency comb. Experimental results present bandwidths of 300nm, spaced by 6.5nm, and more than 200 FWM products spanning over 170nm at ITU-T grid specification.
Fiber-Laser-Based Sensor for Measuring Refractive Index and Solute Concentration of Aqueous Solutions
Authors: Arellano-Sotelo Héctor , Barmenkov Yuri O. , Kir’yanov Alexander V.
Published: February 2023

We report a novel-principle fiber-laser intra-cavity sensor for measuring refractive index and solute concentration of aqueous solutions. The sensor operation is based on a variation of the laser oscillation relaxation frequency (RF, the measured parameter), sensitive to the intra-cavity loss. As the loss includes the reflection coefficient on the frontier aqueous solution - silica fiber cleaved cut, being the laser output coupler and simultaneously the sensor head, the RF becomes affected by the changes in refractive index of the aqueous solution; in turn, because the solution index is proportional to the solute concentration in water, the RF becomes also a function of the latter. The sensor capacity is demonstrated on the example of measurements of sugar concentration in water. A modeling of the sensor operation is presented, allowing its performance optimization
Evaporation in Water-Core Photonic Crystal Fibers
Authors: Ong Jackson S. K. , Facincani Tilon , de Matos Christiano J. S.
Published: February 2023

Index-guiding liquid-core photonic crystal fibers (PCFs) have received considerable attention lately due to their potential applications in sensing, spectroscopy, and nonlinear optics. These waveguides are generally obtained by selectively filling the central hole of a hollow-core PCF with the desired liquid. However, due to the micrometric dimensions of the core, the liquid may quickly evaporate, affecting guidance. In this paper we study evaporation as one of the possible mechanisms responsible for losses in index-guiding liquid-core PCFs. To this end, the evaporation rate of water is examined in capillaries with inner diameters that are similar to those of hollow-core PCFs. It was found that this rate initially decreases and then saturates at a constant value, which in general increased as the inner diameter decreased. The transmission loss of a water-core PCF was then measured over time at a wavelength of 633 nm. An exponential loss increase was detected, which is, indeed, expected if the evaporation rate is constant. The observed characteristic time of ~20 minutes is compatible with the expected evaporation rate. In summary, we find that evaporation is an important issue, which may limit the times over which experiments can be undertaken in liquid-core PCFs whose tips lie in air.