Lateral Eye Research Articles

Multiple dental anomalies accompany unilateral disturbances in abducens and facial nerves: A case report

This article describes the oral rehabilitation of an 8-year-old girl with extensively affected primary and permanent dentition. This report is unique in which distinct dental anomalies including enamel hypoplasia, irregular dentin formation, taurodontism, hpodontia and dens in dente accompany unilateral disturbance of abducens and facial nerves which control the lateral eye movement, and facial expression, respectively. Keywords: enamel hypoplasia; irregular dentin formation; taurodontism; hypodontia; dens in dente; abducens and facial nerves;

Sexually dimorphic gene expression in the lateral eyes of Euphilomedes carcharodonta (Ostracoda, Pancrustacea)

BackgroundThe evolution and development of sexual dimorphism illuminates a central question in biology: How do similar genomes produce different phenotypes? In an XX/XO system especially the state of a sexually dimorphic trait is determined by differences in gene expression, as there are no additional genetic loci in either sex. Here, we examine the XX/XO ostracod crustacean species Euphilomedes carcharodonta. This species exhibits radical sexual dimorphism of their lateral eyes, females have only a tiny simple lateral eye while males have elaborate ommatidial eyes.ResultsWe find that males express three of nine eye-development gene homologs at significantly higher levels during juvenile eye development, compared to females. We also find that most eye-development genes examined are pleiotropic, with high expression levels during embryonic development as well as during juvenile eye development. Later, in adults, we find that phototransduction genes are expressed at higher levels in males than in females, as we might expect when comparing ommatidial to simple eyes.ConclusionsWe show here that expression changes of a handful of developmental genes may underlie the radical difference in a dimorphic character. This work gives an important point of comparison for studying eye evolution and development in the Pancrustacea.Electronic supplementary materialThe online version of this article (doi:10.1186/s13227-015-0026-2) contains supplementary material, which is available to authorized users.

Contrast adaptation in the Limulus lateral eye.

Luminance and contrast adaptation are neuronal mechanisms employed by the visual system to adjust our sensitivity to light. They are mediated by an assortment of cellular and network processes distributed across the retina and visual cortex. Both have been demonstrated in the eyes of many vertebrates, but only luminance adaptation has been shown in invertebrate eyes to date. Since the computational benefits of contrast adaptation should apply to all visual systems, we investigated whether this mechanism operates in horseshoe crab eyes, one of the best-understood neural networks in the animal kingdom. The spike trains of optic nerve fibers were recorded in response to light stimuli modulated randomly in time and delivered to single ommatidia or the whole eye. We found that the retina adapts to both the mean luminance and contrast of a white-noise stimulus, that luminance- and contrast-adaptive processes are largely independent, and that they originate within an ommatidium. Network interactions are not involved. A published computer model that simulates existing knowledge of the horseshoe crab eye did not show contrast adaptation, suggesting that a heretofore unknown mechanism may underlie the phenomenon. This mechanism does not appear to reside in photoreceptors because white-noise analysis of electroretinogram recordings did not show contrast adaptation. The likely site of origin is therefore the spike discharge mechanism of optic nerve fibers. The finding of contrast adaption in a retinal network as simple as the horseshoe crab eye underscores the broader importance of this image processing strategy to vision.

Ipsilaterality serves contralaterality. An explanation for the ipsilateral pathways of the retinal fibers of the binocular vision.

Ipsilaterality serves contralaterality. An explanation for the ipsilateral pathways of the retinal fibers of the binocular vision.

MORPHOMETRIC CHARACTERISTICS OF THE GOLDEN JACKAL POPULATIONS IN EASTERN CROATIA AND EASTERN SERBIA

The aim of the present study was to test whether there are morphological differences between individuals of the golden jackal (Canis aureus L.) from two distant populations living in eastern Croatia and eastern Serbia. Measurements of 28 morphometric characters were done on total of 82 male and female individuals, of which 66 from eastern Croatia and 16 from eastern Serbia. Based on performed data analyses it was confirmed that difference in body morphology exists between populations of the golden jackal from eastern Croatia and eastern Serbia. Individuals from eastern Serbian population are characterized in significantly higher values for: total body length, median ear span, lateral ear span, lateral eye span and neck circumference. Individuals from eastern Croatian population are characterized in higher values for: height at withers, ear length, median eye span, front paw length and carpometacarpal length. Head length was significantly longer in males than in females in both studied populations.

A Reliable Method to Measure Lip Height Using Photogrammetry in Unilateral Cleft Lip Patients

There is still no reliable tool to determine the outcome of the repaired unilateral cleft lip (UCL). The aim of this study was therefore to develop an accurate, reliable tool to measure vertical lip height from photographs. The authors measured the vertical height of the cutaneous and vermilion parts of the lip in 72 anterior-posterior view photographs of 17 patients with repairs to a UCL. Points on the lip's white roll and vermillion were marked on both the cleft and the noncleft sides on each image. Two new concepts were tested. First, photographs were standardized using the horizontal (medial to lateral) eye fissure width (EFW) for calibration. Second, the authors tested the interpupillary line (IPL) and the alar base line (ABL) for their reliability as horizontal lines of reference. Measurements were taken by 2 independent researchers, at 2 different time points each. Overall 2304 data points were obtained and analyzed. Results showed that the method was very effective in measuring the height of the lip on the cleft side with the noncleft side. When using the IPL, inter- and intra-rater reliability was 0.99 to 1.0, with the ABL it varied from 0.91 to 0.99 with one exception at 0.84. The IPL was easier to define because in some subjects the overhanging nasal tip obscured the alar base and gave more consistent measurements possibly because the reconstructed alar base was sometimes indistinct. However, measurements from the IPL can only give the percentage difference between the left and right sides of the lip, whereas those from the ABL can also give exact measurements. Patient examples were given that show how the measurements correlate with clinical assessment. The authors propose this method of photogrammetry with the innovative use of the IPL as a reliable horizontal plane and use of the EFW for calibration as a useful and reliable tool to assess the outcome of UCL repair.

Negative mental imagery in public speaking anxiety: Forming cognitive resistance by taxing visuospatial working memory

Background and objectivesThis study sought to reconcile two lines of research. Previous studies have identified a prevalent and causal role of negative imagery in social phobia and public speaking anxiety; others have demonstrated that lateral eye movements during visualisation of imagery reduce its vividness, most likely by loading the visuospatial sketchpad of working memory. It was hypothesised that using eye movements to reduce the intensity of negative imagery associated with public speaking may reduce anxiety resulting from imagining a public speaking scenario compared to an auditory control task. MethodsForty undergraduate students scoring high in anxiety on the Personal Report of Confidence as a Speaker scale took part. A semi-structured interview established an image that represented the participant's public speaking anxiety, which was then visualised during an eye movement task or a matched auditory task. Reactions to imagining a hypothetical but realistic public speaking scenario were measured. ResultsAs hypothesised, representative imagery was established and reduced in vividness more effectively by the eye movement task than the auditory task. The public speaking scenario was then visualised less vividly and generated less anxiety when imagined after performing the eye movement task than after the auditory task. LimitationsSelf-report measures and a hypothetical scenario rather than actual public speaking were used. Replication is required in larger as well as clinical samples. ConclusionsVisuospatial working memory tasks may preferentially reduce anxiety associated with personal images of feared events, and thus provide cognitive resistance which reduces emotional reactions to imagined, and potentially real-life future stressful experiences.

Differential expression of retinal determination genes in the principal and secondary eyes of Cupiennius salei Keyserling (1877).

BackgroundTranscription factors that determine retinal development seem to be conserved in different phyla throughout the animal kingdom. In most representatives, however, only a few of the involved transcription factors have been sampled and many animal groups remain understudied. In order to fill in the gaps for the chelicerate group of arthropods, we tested the expression pattern of the candidate genes involved in the eye development in the embryo of the wandering spider Cupiennius salei. One main objective was to profile the molecular development of the eyes and to search for possible variation among eye subtype differentiation. A second aim was to form a basis for comparative studies in order to elucidate evolutionary pathways in eye development.ResultsWe screened the spider embryonic transcriptome for retina determination gene candidates and discovered that all except one of the retinal determination genes have been duplicated. Gene expression analysis shows that the two orthologs of all the genes have different expression patterns. The genes are mainly expressed in the developing optic neuropiles of the eyes (lateral furrow, mushroom body, arcuate body) in earlier stages of development (160 to 220 h after egg laying). Later in development (180 to 280 h after egg laying), there is differential expression of the genes in disparate eye vesicles; for example, Cs-otxa is expressed only in posterior-lateral eye vesicles, Cs-otxb, Cs-six1a, and Cs-six3b in all three secondary eye vesicles, Cs-pax6a only in principal eye vesicles, Cs-six1b in posterior-median, and posterior-lateral eye vesicles, and Cs-six3a in lateral and principal eye vesicles.ConclusionsPrinciple eye development shows pax6a (ey) expression, suggesting pax6 dependence, although secondary eyes develop independently of pax6 genes and show differential expression of several retinal determination genes. Comparing this with the other arthropods suggests that pax6-dependent median eye development is a ground pattern of eye development in this group and that the ocelli of insects, the median eyes of chelicerates, and nauplius eyes can be homologised. The expression pattern of the investigated genes makes it possible to distinguish between secondary eyes and principal eyes. Differences of gene expression among the different lateral eyes indicate disparate function combined with genetic drift.Electronic supplementary materialThe online version of this article (doi:10.1186/s13227-015-0010-x) contains supplementary material, which is available to authorized users.

A study on the natural history of scanning behaviour in patients with visual field defects after stroke

BackgroundA visual field defect (VFD) is a common consequence of stroke with a detrimental effect upon the survivors’ functional ability and quality of life. The identification of effective treatments for VFD is a key priority relating to life post-stroke. Understanding the natural evolution of scanning compensation over time may have important ramifications for the development of efficacious therapies.The study aims to unravel the natural history of visual scanning behaviour in patients with VFD. The assessment of scanning patterns in the acute to chronic stages of stroke will reveal who does and does not learn to compensate for vision loss.Methods/DesignEye-tracking glasses are used to delineate eye movements in a cohort of 100 stroke patients immediately after stroke, and additionally at 6 and 12 months post-stroke. The longitudinal study will assess eye movements in static (sitting) and dynamic (walking) conditions.The primary outcome constitutes the change of lateral eye movements from the acute to chronic stages of stroke. Secondary outcomes include changes of lateral eye movements over time as a function of subgroup characteristics, such as side of VFD, stroke location, stroke severity and cognitive functioning.DiscussionThe longitudinal comparison of patients who do and do not learn compensatory scanning techniques may reveal important prognostic markers of natural recovery. Importantly, it may also help to determine the most effective treatment window for visual rehabilitation.

Lateral Eye Deviation and Post-Stroke Spatial Neglect (P1.208)

Lateral Eye Deviation and Post-Stroke Spatial Neglect (P1.208)

Color difference threshold of chromostereopsis induced by flat display emission.

The study of chromostereopsis has gained attention in the backdrop of the use of computer displays in daily life. In this context, we analyze the illusory depth sense using planar color images presented on a computer screen. We determine the color difference threshold required to induce an illusory sense of depth psychometrically using a constant stimuli paradigm. Isoluminant stimuli are presented on a computer screen, which stimuli are aligned along the blue–red line in the computer display CIE xyY color space. Stereo disparity is generated by increasing the color difference between the central and surrounding areas of the stimuli with both areas consisting of random dots on a black background. The observed altering of illusory depth sense, thus also stereo disparity is validated using the “center-of-gravity” model. The induced illusory sense of the depth effect undergoes color reversal upon varying the binocular lateral eye pupil covering conditions (lateral or medial). Analysis of the retinal image point spread function for the display red and blue pixel radiation validates the altering of chromostereopsis retinal disparity achieved by increasing the color difference, and also the chromostereopsis color reversal caused by varying the eye pupil covering conditions.

Infrared-Based Blink-Detecting Glasses for Facial Pacing

IMPORTANCE Facial paralysis remains one of the most challenging conditions to effectively manage, often causing life-altering deficits in both function and appearance. Facial rehabilitation via pacing and robotic technology has great yet unmet potential. A critical first step toward reanimating symmetrical facial movement in cases of unilateral paralysis is the detection of healthy movement to use as a trigger for stimulated movement. OBJECTIVE To test a blink detection system that can be attached to standard eyeglasses and used as part of a closed-loop facial pacing system. DESIGN, SETTING, AND PARTICIPANTS Standard safety glasses were equipped with an infrared (IR) emitter-detector unit, oriented horizontally across the palpebral fissure, creating a monitored IR beam that became interrupted when the eyelids closed, and were tested in 24 healthy volunteers from a tertiary care facial nerve center community. MAIN OUTCOMES AND MEASURES Video-quantified blinking was compared with both IR sensor signal magnitude and rate of change in healthy participants with their gaze in repose, while they shifted their gaze from central to far-peripheral positions, and during the production of particular facial expressions. RESULTS Blink detection based on signal magnitude achieved 100% sensitivity in forward gaze but generated false detections on downward gaze. Calculations of peak rate of signal change (first derivative) typically distinguished blinks from gaze-related eyelid movements. During forward gaze, 87% of detected blink events were true positives, 11% were false positives, and 2% were false negatives. Of the 11% false positives, 6% were associated with partial eyelid closures. During gaze changes, false blink detection occurred 6% of the time during lateral eye movements, 10% of the time during upward movements, 47% of the time during downward movements, and 6% of the time for movements from an upward or downward gaze back to the primary gaze. Facial expressions disrupted sensor output if they caused substantial squinting or shifted the glasses. CONCLUSIONS AND RELEVANCE Our blink detection system provides a reliable, noninvasive indication of eyelid closure using an invisible light beam passing in front of the eye. Future versions will aim to mitigate detection errors by using multiple IR emitter-detector units mounted on glasses, and alternative frame designs may reduce shifting of the sensors relative to the eye during facial movements.

Early sensitivity for eyes within faces: A new neuronal account of holistic and featural processing

Eyes are central to face processing however their role in early face encoding as reflected by the N170 ERP component is unclear. Using eye tracking to enforce fixation on specific facial features, we found that the N170 was larger for fixation on the eyes compared to fixation on the forehead, nasion, nose or mouth, which all yielded similar amplitudes. This eye sensitivity was seen in both upright and inverted faces and was lost in eyeless faces, demonstrating it was due to the presence of eyes at fovea. Upright eyeless faces elicited largest N170 at nose fixation. Importantly, the N170 face inversion effect (FIE) was strongly attenuated in eyeless faces when fixation was on the eyes but was less attenuated for nose fixation and was normal when fixation was on the mouth. These results suggest the impact of eye removal on the N170 FIE is a function of the angular distance between the fixated feature and the eye location. We propose the Lateral Inhibition, Face Template and Eye Detector based (LIFTED) model which accounts for all the present N170 results including the FIE and its interaction with eye removal. Although eyes elicit the largest N170 response, reflecting the activity of an eye detector, the processing of upright faces is holistic and entails an inhibitory mechanism from neurons coding parafoveal information onto neurons coding foveal information. The LIFTED model provides a neuronal account of holistic and featural processing involved in upright and inverted faces and offers precise predictions for further testing.

A Paleozoic Stem Group to Mite Harvestmen Revealed through Integration of Phylogenetics and Development

Successfully placing fossils in phylogenies is integral to understanding the tree of life. Crown-group Paleozoic members of the arachnid order Opiliones are indicative of ancient origins and one of the earliest arthropod terrestrialization events [1, 2]. Opiliones epitomize morphological stasis, and all known fossils have been placed within the four extant suborders [3-5]. Here we report a Carboniferous harvestman species, Hastocularis argusgen. nov., sp. nov., reconstructed with microtomography (microCT). Phylogenetic analysis recovers this species, and the Devonian Eophalangium sheari, as members of an extinct harvestman clade. We establish the suborder Tetrophthalmi subordo nov., which bore four eyes, to accommodate H.argus and E.sheari, the latter previously considered to be a phalangid [6-9]. Furthermore, embryonic gene expression in the extant species Phalangium opilio demonstrates vestiges of lateral eye tubercles. These lateral eyes are lost in all crown-group Phalangida, but are observed in both our fossil and outgroup chelicerate orders. These data independently corroborate the diagnosis of two eye pairs in the fossil and demonstrate retention of eyes of separate evolutionary origins in modern harvestmen [10-12]. The discovery of Tetrophthalmi alters molecular divergence time estimates, supporting Carboniferous rather than Devonian diversification for extant suborders and directly impacting inferences of terrestrialization history and biogeography. Multidisciplinary approaches integrating fossil and neontological data increase confidence in phylogenies and elucidate evolutionary history.

The functional oculomotor network and saccadic cognitive control in healthy elders

Decline in executive function is the most common age-associated cognitive deficit and may be a risk factor for neurodegenerative disease. The antisaccade (AS) task involves inhibition of a prepotent visuomotor response and is a well-validated executive function test in aging and neurodegeneration. We investigated the functional connectivity of the cortical oculomotor network during successful AS performance in healthy elders. Elevated BOLD activity in the right lateral frontal eye field (rlatFEF), a region linked to volume loss in individuals with impaired AS performance, was associated with worse AS performance and weaker network efficiency. In contrast, hub integrity of the right dorsolateral prefrontal cortex (rDLPFC) and anterior cingulate cortex (rACC) was associated with better AS performance. These data suggest that while several right lateral frontal regions are central nodes in the oculomotor network, the rlatFEF demonstrates early neural aberrations and the rDLPFC and rACC continue to support inhibitory cognitive control in healthy elders. We conclude that alterations in AS task functional connectivity, quantified as hub and network efficiency, may be clinically-relevant biomarkers of cognitive decline in executive functioning.

Rotation of the Eyes (Not the Head) Potentiates the Postauricular Muscle Response

The authors investigated how eye and head rotation modulate the human postauricular muscle response (PAMR), to determine the optimal strategy for potentiating the PAMR, or minimizing it to reduce contamination of small neurogenic responses. The authors recorded the PAMR evoked by binaural bipolar clicks (50 dB SL, 360 µsec per phase with 53-msec interval) from behind the right ear of 12 normally hearing adults, and attempted to enhance it with (a) voluntary ear contraction alone, (b) head rotation alone (with the eyes forward-directed and tracking a target attached to the head), or (c) by lateral eye movement alone (toward the right measurement side, with the head facing forward). When the head alone was rotated with eyes fixed relative to the head, the PAMR increased only slightly in some subjects, as did the ongoing electromyography (EMG) (probably due to EMG activity from nearby neck muscles). On returning the head to the forward control position, the PAMR dropped rapidly to control amplitudes. When the eyes alone were rotated, both the EMG and the PAMR increased markedly in most subjects, and returning the eyes to their control position produced a gradual return to control amplitudes. Voluntary PAM contraction (in those subjects who could accomplish it) increased the EMG tone and the PAMR amplitude concomitantly, with vigorous voluntary PAM contraction saturating the PAMR but not the EMG. Head rotation alone was not effective in potentiating the PAMR when lateral eye movement relative to the head was avoided during the head rotation maneuver. When lateral eye movement was controlled appropriately, the PAMR could be potentiated reliably, or reliably avoided when recording smaller neurogenic responses. If head rotation was used to optimize the PAMR without explicit control of eye movement, a false impression of variability was produced.

Successful reconstruction of complex pediatric nasal lesions: improving outcomes using dermal regenerative templates.

Background:Dermal regenerate templates are currently widely used in both adult and pediatric burn reconstruction. Despite this, the safety and efficacy of regenerate templates combined with full-thickness skin grafts for the reconstruction of pediatric facial defects traditionally treated with local flaps is not widely published. The aim of this study is to report the safety and efficacy of pediatric nasal defect reconstruction using regenerative templates/full-thickness skin grafts.Methods:A retrospective review of one institution’s experience with pediatric nasal defects treated with regenerative templates was performed. All patients (n = 4) were treated with a multistage protocol. Two reviewers independently assigned Visual Analogue Cosmetic Scale (VACS) scores: 1 surgeon and 1 nonsurgical researcher not involved in patient care. Standardized photographs (anteroposterior, oblique, lateral, and worm’s eye view) were assigned VACS scores according to a 100-point scale: “abhorrent,” 0–24; “poor,” 25–49; “moderate,” 50–74; and “excellent,” 75–100. Statistical analysis was performed using Mann-Whitney U and Wilcoxon paired signed-rank tests.Results:Four patients (2 boys and 2 girls, average age 6.8 yr) who met the inclusion criteria were identified. A total of 5 nasal lesions (2 spitz nevi, 1 vascular lesion, and 2 congenital nevi) were removed. The preoperative VACS score was 45.2 (range, 5–70), compared with 84.5 (range, 45–100) postoperatively (P <0.000). There was no significant difference between raters (preoperative, P = 0.346; postoperative, P = 0.678).Conclusions:The reconstruction of complex pediatric nasal lesions using dermal regenerative templates and full-thickness postauricular skin grafts is safe and effective, and associated with low morbidity and significant improvement in VACS scores.

Case Report and Theoretical Description of Accelerated Resolution Therapy (ART) for Military-Related Post-Traumatic Stress Disorder

This article describes a new, brief exposure-based psychotherapy known as Accelerated Resolution Therapy (ART) that is currently being evaluated as a treatment for combat-related post-traumatic stress disorder (PTSD). We describe a case report of an Army veteran with combat-related PTSD who was treated with 2 sessions of ART and experienced significant clinical improvement. We then discuss the theoretical basis and major components of the ART protocol, including use of lateral left-right eye movements, and differentiate ART with evidence-based psychotherapies currently endorsed by the Department of Defense and Veterans Administration. The number of military personnel who have served in the wars in Iraq and Afghanistan and are afflicted with PTSD is likely in the hundreds of thousands. The ART protocol, which is delivered in 2 to 5 sessions and without homework, uses the psychotherapeutic practices of imaginal exposure and imagery rescripting (IR) facilitated through sets of eye movements. In addition to its brevity, a novel component of ART is use of IR to "replace" negative imagery (and other sensations) with positive imagery. This theoretical description of ART and single case report provide a rationale for future formal evaluation of ART for treatment of military-related PTSD.

Neurological debut of non-Hodgkin’s lymphoma: the complexity of diagnosis

A rare case of system non-Hodgkin’s lymphoma manifested with oculomotor abnormalities is presented in the paper. In the patient examined, initial symptoms were diplopia and restriction of the lateral eye movements; these symptoms appeared on the background of the intense headaches. The death resulted from the acute cardio-pulmonary failure. On postmortem study, B-cell lymphoma of multiple localizations, including the central nervous system, heart, lymph nodes, spleen and liver, was found.

Randomized clinical efficacy of superficial peeling with 85% lactic acid versus 70% glycolic acid

BACKGROUND:Peeling is a procedure which aims to accelerate the process of skin exfoliation.OBJECTIVES Development of formulations containing lactic acid at 85% or glycolic acid at 70% and the evaluation of these formulations on clinical efficacy in reduction of fine wrinkles. METHODS Preliminary stability tests were carried out and an in vivo study was performed with three groups with 9 representatives each. One was the control group, which used only sunscreen; another one used lactic acid+sunscreen, and the last group used acid glycolic+sunscreen. Clinical efficacy was assessed with a CCD color microscope, through the digitization of images before and after treatment. The applications were carried out by a dermatologist, once a mont h every 30 days, during 3 months. The area with wrinkles was calculated by planimetry point counting, in accordance with Mandarin-de-Lacerda. RESULTS The formulations were stable in the visual and Ph evaluation. There was no improvement in the control group; for lactic acid, there was significant improvement after the second peeling application on the outer lateral area of the right eye and after the third application on the outer lateral area of the left eye. For the glycolic acid group, there was significant improvement in the outer lateral area of the left eye after the first application, and of the right eye region, after three applications. The formulations used must be kept under refrigeration and should be manipulated every 30 days. CONCLUSIONS Both peelings were effective in reducing fine wrinkles of the outer lateral eye area after three applications (p≤0.05%). It was observed that peeling efficacy in the external-lateral region of one eye might be different compared with that in skin of the external-lateral region of the other eye, relative to the speed of skin improvement.