Frontal Vision Research Articles

OUR EXPERIENCE WITH THE CORRECTION OF PROTRUDING EARS: CLINICAL CASE SERIES

Many methods have been developed to correct protruding ears, but the best one should be simple, reliable, and reproducible. Obectives: The purpose of our study is to evaluate the effectiveness of protruding ear correction. Materials and Method: This is a 5-year retrospective study (2018–2023) of 103 patients with protruding ears. Patients were followed up for at least a year after surgery. A modified Mustarde technique procedure was applied. Incision made high at the level of the retroauricular projection of the retroauricular fossa to make it more difficult to see. After that, the skin is carefully separates from the cartilage. The cartilage is trimmed followed by the formation and modeling of the cartilage configuratio so that the auricle acquires a normal and natural shape. We stabilize the newly reconstructed antihelix using two to three stitches of Vycryl 4/0. Elastic bandage is worn for seventh day. The sutures were removed at the consultation on the 7–10 postoperative day. Patients were followed up at 3, 6, and 12 months followed by yearly intervals for 3-5 years. Data on functional and aesthetic outcomes were documented. Preoperative and postoperative photographs were also taken of all patients. The result was assessed on a visual analogue scale by the patient. Patient satisfaction was assessed in accordance with the indicators of the questionnaire, in which their degree of satisfaction was assessed on a 4-point scale: 1 (poor), 2 (satisfactory), 3 (good) and 4 (Great). Parameters included: improvement in the natural contour of the ears, improvement in frontal vision, improvement in the asymmetry of the concho-mastoid angle. Results: In study, hemorrhages, hematomas, keloid formations, suture extrusion, skin and cartilage infections, skin necrosis and recurrences were not observed in any patient. The average score of the the patient's is 8.4. The average concho-mastoid distance before the operation is 2.2 cm, after the operation it decreases to 1.4 cm. Clinical evaluation showed excellent results (58.7%), good results (28.6%), satisfactory results (12.7%) and without poor results. Conclusion: Correction of protruding ears using this technique is safe and simple. Serious complications were not observed, good aesthetic results were obtained. The applied technique is universal, gives good results and has a low level of complications.

Detection of Behavioral Patterns Employing a Hybrid Approach of Computational Techniques

As far as the present state is concerned in detecting the behavioral pattern of humans (subject) using morphological image processing, a considerable portion of the study has been conducted utilizing frontal vision data of human faces. The present research work had used a side vision of human-face data to develop a theoretical framework via a hybrid analytical model approach. In this example, hybridization includes an artificial neural network (ANN) with a genetic algorithm (GA). We researched the geometrical properties extracted from side-vision human-face data. An additional study was conducted to determine the ideal number of geometrical characteristics to pick while clustering. The close vicinity of minimum distance measurements is done for these clusters, mapped for proper classification and decision process of behavioral pattern. To identify the data acquired, support vector machines and artificial neural networks are utilized. A method known as an adaptive-unidirectional associative memory (AUTAM) was used to map one side of a human face to the other side of the same subject. The behavioral pattern has been detected based on two-class problem classification, and the decision process has been done using a genetic algorithm with best-fit measurements. The developed algorithm in the present work has been tested by considering a dataset of 100 subjects and tested using standard databases like FERET, Multi-PIE, Yale Face database, RTR, CASIA, etc. The complexity measures have also been calculated under worst-case and best-case situations.

Helmet Prototype Response Time Assessment using NCAA Division 1 Collegiate Football Athletes

Background: With advances in concussion research, an increasing amount of resources are being allocated to advancing football helmet technology. Objective: This study assesses the claim that a new modified helmet prototype provides greater field of view for the user as compared to a commonly worn helmet by players. Method: The helmets—Riddell SpeedFlex and the modified helmet—were compared based on user response time while performing a response test task using the FITLIGHT Trainer system, actual helmet field of view blockage, users’ subjective perception of field of view, and balance tests. Eighteen National Collegiate Athletic Association (NCAA) Division 1 American football student-athletes completed the response test task and questionnaire. Results: The results demonstrate evidence that the SpeedFlex helmet provided by the equipment staff significantly increases wearers’ response times, F(2,20) = 5.646, p < 0.05. Also, while the quantification of the field of view perception was similar across helmet types, the student-athlete participants perceived the modified helmet to have significantly more field of view while performing the response test task, 1.56 v. 2.56; p < 0.05 for frontal vision and 2.83 v. 5.39; p < 0.05 for peripheral vision. Conclusion: In addition to the findings, this study also lays out a response time test protocol using the FITLIGHT Trainer system that can be used for assessment of response time testing of football and other helmets in future studies.

The Hawk-Eyed Songbird: Retinal Morphology, Eye Shape, and Visual Fields of an Aerial Insectivore.

Swallows are a unique group of songbirds because they are active-pursuit predators that execute all aspects of hunting prey in flight: search, detection, pursuit, and capture. We show that swallows have evolved a visual system that is unlike that of any other studied songbird. Swallows have a bifoveate retina that provides sharp lateral and frontal vision, an unusually long eye that enhances spatial resolution, a large posterior blind area, and a narrow binocular field. We also show that swallows and diurnal raptors (hawks and falcons) have converged on a similar visual configuration but that, interestingly, predatory songbirds that ambush prey (flycatchers) have not converged on the same suite of traits. Despite the commonly held belief that predators rely on binocular vision, the temporal (frontally projecting) fovea present in swallows-but not present in other songbirds-is likely not involved in binocular vision. Instead, swallows have four nonoverlapping foveae in a 100° arc around the beak, which can improve the tracking of frontally located aerial prey that are engaging in evasive maneuvers. Overall, vision in pursuit predators reflects the complex sensory demands of hunting in the air at high speeds and emphasizes the importance of acute frontal vision in predators.

Paleoparasitological analysis of the extinct Myotragus balearicus Bate 1909 (Artiodactyla, Caprinae) from Mallorca (Balearic Islands, Western Mediterranean)

Myotragus balearicus (Artiodactyla, Caprinae) is an extinct caprine endemic of the Eastern Balearic Islands or Gymnesics (i.e., Mallorca, Menorca and surrounding islets, Western Mediterranean Sea). In spite of its small size, c. 50cm height at the shoulder, it was the largest mammal inhabiting these islands until the human arrival, and it had peculiar short legs and frontal vision. It disappeared between 2830 and 2210calBCE. The coprolites here studied were recovered from Cova Estreta, in Pollença, Mallorca. The samples were subjected to microscopic examination and enzyme-linked immunosorbent assays (ELISA) for E. histolytica/E. dispar, Giardia intestinalis and Cryptosporidium parvum. This study provides new paleoparasitological data from an extinct animal species of the Holocene period. The microscopy revealed one sample containing uninucleated-cyst of Entamoeba sp., whereas ELISA detected nine positive samples for Cryptosporidium sp. The finding of these protozoans can help in the discussion of its extinction cause and demonstrates the antiquity and the evolutionary history of host-parasite relationships between protozoa and caprines since the Messinian.

Clinical and Radiographic Recovery from Postpartum Cerebral Angiopathy with Conservative Management

A 31 year old woman presented with severe frontal headache and blurry vision about 6 days after her normal delivery. Her blood pressure was 193/111 mmHg and her liver and renal function tests and coagulation studies was normal. Her CT Head showed bifrontal subarachnoid hemorrhage (SAH) and MR Angiogram showed characteristic “beaded” appearance of multiple branches of the middle and anterior cerebral arteries bilaterally. The patient was treated with nimodipine and normal saline infusions. Her repeat MRA after one week showed resolution of SAH with normal anterior, middle, and posterior cerebral arteries. The patient was diagnosed with Postpartum cerebral angiopathy.

Role of the trochlear nerve in eye abduction and frontal vision of the red‐eared slider turtle (Trachemys scripta elegans)

Horizontal head rotation evokes significant responses from trochlear motoneurons of turtle that suggests they have a functional role in abduction of the eyes like that in frontal-eyed mammals. The finding is unexpected given that the turtle is generally considered lateral-eyed and assumed to have eye movements instead like that of lateral-eyed mammals, in which innervation of the superior oblique muscle by the trochlear nerve (nIV) produces intorsion, elevation, and adduction (not abduction). Using an isolated turtle head preparation with the brain removed, glass suction electrodes were used to stimulate nIV with trains of current pulses. Eyes were monitored via an infrared camera with the head placed in a gimble to quantify eye rotations and their directions. Stimulations of nIV evoked intorsion, elevation, and abduction. Dissection of the superior oblique muscle identified lines of action and a location of insertion on the eye, which supported kinematics evoked by nIV stimulation. Eye positions in alert behaving turtles with their head extended were compared with that when their heads were retracted in the carapace. When the head was retracted, there was a reduction in interpupillary distance and an increase in binocular overlap. Occlusion of peripheral fields by the carapace forces the turtle to a more frontal-eyed state, perhaps the reason for the action of abduction by the superior oblique muscle. These findings support why trochlear motoneurons in turtle respond in the same way as abducens motoneurons to horizontal rotations, an unusual characteristic of vestibulo-ocular physiology in comparison with other mammalian lateral-eyed species.

The optic chiasm: a turning point in the evolution of eye/hand coordination.

The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate.The primate visual system is ideally suited for tasks within arm’s length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal vision and visually guided forelimbs, and also suggests a new perspective on vision convergence in prey and predatory animals.

Understanding bird collisions with man‐made objects: a sensory ecology approach

Sensory ecology investigates the information that underlies an animal’s interactions with its environment. A sensory ecology framework is used here to seek to assess why flying birds collide with prominent structures, such as power lines, fences, communication masts, wind turbines and buildings, which intrude into the open airspace. Such collisions occur under conditions of both high and low visibility. It is argued that a human perspective of the problems posed by these obstacles is unhelpful. Birds live in different visual worlds and key aspects of these differences are summarized. When in flight, birds may turn their heads in both pitch and yaw to look down, either with the binocular field or with the lateral part of an eye’s visual field. Such behaviour may be usual and results in certain species being at least temporarily blind in the direction of travel. Furthermore, even if birds are looking ahead, frontal vision may not be in high resolution. In general, high resolution occurs in the lateral fields of view and frontal vision in birds may be tuned for the detection of movement concerned with the extraction of information from the optical flow field, rather than the detection of high spatial detail. Birds probably employ lateral vision for the detection of conspecifics, foraging opportunities and predators. The detection of these may be more important than simply looking ahead during flight in the open airspace. Birds in flight may predict that the environment ahead is not cluttered. Even if they are facing forward, they may fail to see an obstacle as they may not predict obstructions; perceptually they have no ‘prior’ for human artefacts such as buildings, power wires or wind turbines. Birds have only a restricted range of flight speeds that can be used to adjust their rate of gain of visual information as the sensory challenges of the environment change. It is argued that to reduce collisions with known hazards, something placed upon the ground may be more important than something placed on the obstacle itself. Foraging patches, conspecific models or alerting sounds placed a suitable distance from the hazard may be an effective way of reducing collisions in certain locations. However, there is unlikely to be a single effective way to reduce collisions for multiple species at any one site. Warning or diversion and distraction solutions may need to be tailored for particular target species.

Binocular vision in theropod dinosaurs

ABSTRACT The binocular fields of view of seven theropod dinosaurs are mapped using sculpted life reconstructions of their heads and techniques adopted from ophthalmic field perimetry. The tall, narrow snout and laterally facing eyes of the allosauroids Allosaurus and Carcharodontosaurus restricted binocular vision to a region only approximately 20° wide, comparable to that of modern crocodiles. In contrast, the coelurosaurs Daspletosaurus, Tyrannosaurus, Nanotyrannus, Velociraptor, and Troodon had cranial designs that afforded binocular fields between 45–60° in width, similar to those of modern raptorial birds. Binocular field width and predatory style (ambush versus pursuit) is examined for extant taxa, along with a discussion of cranial adaptations that enhance binocular vision. The progressive increase in frontal vision in the tyrannosaurids culminates in broader binocular overlap than that of a modern hawk. The visual acuity and the limiting far point for stereopsis is estimated for Tyrannosaurus based on reptilian and avian models.

Anal incontinence: evaluation of the anal sphincter by endoscopic ultrasound

incontinence (gas and liquid stools) shortly after proctologic surgery (fistulectomy). She did not report any obstetric trauma. We performed an anal inspection and a digital rectal examination. There were no anatomical defects, but a severe hypotonic anal sphincter was encountered. Since there is a radial-scanning ultrasound endoscope with frontal vision (Pentax EG3630UR) available in our Unit, an endoscopic review of the rectal and sigmoid mucosa was carried out, with no abnormalities being detected. A radial endoscopic ultrasonography was performed using a frequency of 7.5 MHz during the same exploration. At the middle of the anal canal, the internal anal sphincter is seen as a hypoechoic ring under normal conditions (Fig. 1). In this patient there was a 50% defect at this hypoechoic band representing the internal anal sphincter (Fig. 2). No defects in the external anal sphincter were seen, other than it was slightly thin. The patient had fecal incontinence due to proctologic surgery with internal and sphincter damage. Therefore, the patient had fecal incontinence due to her proctologic surgery having damaged the internal anal sphincter. An anorectal manometry was performed, and it confirmed the internal anal sphincter hypotonia and also showed a lower pressure at the external anal sphincter. Endoscopic ultrasonography of the anal canal is an accurate technique for the evaluation of the external and internal anal sphincters (1-3). The sensitivity for the detection of abnormalities at both sphincters is about 100%, since the specificity for defects in the external sphincter is 100%, and 95.5% regarding the internal sphincter (4). Endoanal ultrasound is essential in order to plan fecal incontinence surgery, and mandatory along with a functional study of the anal canal in Units where pelvic floor surgery is performed. Anal incontinence: evaluation of the anal sphincter by endoscopic ultrasound

Du noyau abducens à la mémoire spatiale : un parcours oculomoteur

Advances in our knowledge on eye movements over the last 25 years are reviewed, focusing on the author's experience. First, the advantages of binocular frontal vision, which is a common characteristic of all predator mammals, are compared to those of lateral vision, characterizing their preys. Binocular frontal vision implies a perfect parallelism of both eyes, which is ensured in the pons by means of the abducens nucleus, controlling abduction as well as adduction. The pathological example of the "one-and-a-half" syndrome, in which the abducens nucleus and the adjacent medial longitudinal fasciculus are simultaneously impaired, is described. The main brainstem syndromes involving vertical eye movements are also reviewed: in particular, the third nerve nucleus syndrome, in which both ipsilateral third nerve paralysis and contralateral superior rectus paralysis (with hypotropia) result from a unilateral third nerve nucleus lesion. A case of upbeat nystagmus (in the primary position of gaze) due to a small upper pontine lesion, probably affecting the ventral tegmental tract (VTT) is also reported. This is an opportunity to emphasize that, although a number of cases of upbeat nystagmus due to focal brainstem lesions affecting the upward vestibular pathway (UVP)--either at the upper pontine (VTT) or caudal medullary level--exist in the literature, no convincing cases with downbeat nystagmus (in the primary position of gaze) due to a focal brainstem lesion have been reported. Downbeat nystagmus could result from a UVP hyperactivity (secondary to a floccular lesion) and the notion that this pathway is physiologically predominant compared to the downward pathway, maybe due to gravity, is developed. A new hypothesis about the role of the caudal medulla in UVP is also proposed. Next, the cortical control of saccadic eye movements is reviewed, with a reminder that reflexive saccades are mainly triggered by the parietal eye field whereas intentional saccades depend upon the frontal eye field. The inhibition of reflexive saccades is mainly controlled by the dorsolateral frontal cortex (DLPFC), i.e. area 46 of Brodmann. A few examples of the use of saccades as a research tool and model in cognitive neurosciences are given. The use of memory-guided saccades allowed us to study spatial memory and led us to propose a relatively original conception of the cortical control of spatial memory in which the DLPFC, the parahippocampal cortex and the hippocampal formation could be involved successively according to specific periods of time. An experiment using functional magnetic resonance imaging in a paradigm studying decision is described, again with the involvement of the DLPFC in the decisional process. Lastly, the usefulness of eye movements in clinical neuro-ophthalmology at the bedside as well as in neurophysiological or even neuropsychological research in the laboratory is emphasized.

Lateral asymmetry of eye use in Octopus vulgaris

The lateralization of sensory and motor functions has been recently demonstrated in various groups of vertebrates. We examined lateral asymmetry of eye use in Octopus vulgaris by behavioural methods. Octopus vulgaris uses monocular vision almost exclusively and can move its eyes independently. The amount of binocular vision is small because the eyes are on the sides of the head. We tested eight octopuses in two conditions (one with and one without moving stimuli) where the use of the eye for frontal vision could be determined unequivocally. Data were recorded on videotape. All animals showed a preference for one eye (five left, three right). There was no correlation between eye use and the animal's direction of movement. Pigmentation of the ventral side of the arms tended to be most intense on the side of the preferred eye and the body was most pigmented on the side of the eye currently in use. We found no sex differences for visual lateralization. Pigmentation of the ventral side of the arms was lighter in females than in males. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

GABAergic and non-GABAergic neurons in the nucleus of the optic tract project to the superior colliculus: an ultrastructural retrograde tracer and immunocytochemical study in the rabbit.

Both the nucleus of the optic tract (NOT) and the superior colliculus (SC) are thought to play important roles in the regulation of eye movements. The superior colliculus contributes to visual orientation and saccades, and the nucleus of the optic tract contributes to the detection of slow movements of the visual surround. Recently, a GABAergic projection has been described between these two nuclei in the cat, a species with frontal vision. The present study aimed at determining whether a similar GABAergic pathway exists in the rabbit, a species with lateral vision. To study this pathway we used the retrograde tracer cholera-toxin (CTB) to identify NOT neurons projecting to the SC and GABA-antibody immunostaining to identify GABA-containing neurons and processes. CTB injections into the superficial laminae of the SC showed that GABAergic and non-GABAergic neurons in the NOT project to the SC. Both types of neurons have structural characteristics similar to other projection neurons in the NOT. In contrast to the NOT neurons projecting to the inferior olive (IO) which are mainly located in the rostral NOT, the GABAergic and non-GABAergic NOT-SC neurons are situated throughout the nucleus. The somata and principal dendrites of both neuron types receive numerous synaptic contacts from GABAergic terminals and only a few from retinals. The NOT projection neurons to the SC thus establish prominent excitatory and inhibitory links between the two structures, suggesting the existence of separate circuits that could interact through a GABAergic and non-GABAergic NOT-SC projection. It is further suggested that these circuits may be involved in the regulation of saccades in the SC during optokinetic nystagmus.

Peripheral vision and age-related differences in dynamic balance

The purpose of this study was to investigate the role of peripheral visual cues in locomotor equilibrium as a function of age in 3- to 12-year-old children and adults. Peripheral visual restrictions (PVR), limiting frontal vision to either 30, 60 or 120 degrees, were applied to subjects walking on a narrow beam. The subjects' locomotor equilibrium performances were evaluated in terms of the locomotor speed, which constitutes a good index to the difficulty of locomotor balancing. The results showed that the influence of peripheral visual cues on locomotor equilibrium control did not vary monotonously with age. The peripheral visual contribution to dynamic balance control increased from 3 to 6 years of age, with a maximum in 6-year-old children. The peripheral visual influence on locomotor equilibrium control then disappeared suddenly in the 7-year-old children. It tended to increase again from 8–9 years of age to adulthood. In adults, the peripheral visual contribution to locomotor equilibrium that we have described previously was confirmed and compared to that involved in postural control. It is concluded from these results that late improvements occur in locomotor balance control during childhood.

The Distribution of Ganglion Cells in the Retina and Visual Acuity of Minke Whale.

In order to understand the visual ability of baleen whale, the distribution of ganglion cells in the retina of minke whale Balaenoptera acutorostrata was examined. The mean diameter of ganglion cells in the retina of minke whale was 42.9μm, which was greater than those of terrestrial mammals. The distribution of the ganglion cells in the retina was irregular and two high density areas existed in the temporal and rostral sectors. The rostral and temporal areas of high density seem to be related to side vision and frontal vision, respectively. Cell density measurement gave a visual acuity value of 4 cycles/degree (7 min of arc). This value for the minke whale did not differ greatly from those of other cetaceans and was similar to some terrestrial herbivorous mammals.

Age-dependent changes in visual acuity and retinal morphology in pigeons

The visual acuities of 17 pigeons that ranged in age from 2 to 17 years were tested with high-contrast, square-wave gratings. A systematic decline in visual acuity was observed that was well described by a logarithmic function. Pupillary diameter also declined with age, which decreased retinal illumination, but increased depth of focus. A small amount of presbyopia also was observed. Both the decrease in retinal illumination and the presbyopia accounted for only a trivial proportion of the acuity loss. No relationship between corneal or lenticular density and age was observed. Ophthalmoscopic examination of the optic media revealed no abnormalities associated with age. Microscopic examination of the area dorsalis of the retina (the high-density region specialized for frontal vision) revealed age-related losses of up to 33% of photoreceptors and 23% of cells in the ganglion-cell layer. A study of the photoreceptor layer within area dorsalis indicated that single-cone densities were unaffected by aging whereas the double-cone densities, which are the predominant photoreceptor type in the area dorsalis, were reduced in number by about one third. Calculation of the Nyquist limit both for photoreceptors and ganglion cells suggested that the decreased retinal density together with the decreased retinal illumination and presbyopia could not account for all of the observed acuity loss.

The projection of the visual field upon the retina of the pigeon

Co-ordinates in the visual field of the pigeon eye were located in the eye cup anatomically by marking the position of the trans-scleral image. The retinal horizon and vertical meridia at azimuths 0 deg (frontal field) and 90 deg (lateral field) were located. Approximately 18 deg of binocular field are available in frontal vision and the frontal meridian projects to temporal retina outside the red field. Spatial distributions of ganglion cells, displaced ganglion cells, and centrifugal terminals were located in the eye cup. Retinal magnification factors in the posterior pole and temporal periphery are close to 120μ/deg.

The pigeon's distant visual acuity as a function of viewing angle

Distant visual acuity was determined for several viewing angles in two restrained White Carneaux pigeons. The behavioral technique was a classical conditioning procedure that paired presentation of sinusoidal gratings with shock. A conditioned heart rate acceleration during the grating presentation indicated resolution of the grating. The birds' acuity was fairly uniform across a large range of their lateral visual field; performance decreased slightly for posterior stimulus placement and sharply for frontal placements. The data suggest that foveal viewing is relatively less advantageous for acuity in pigeons than in humans. The data are also consistent with the current view that pigeons are myopic in frontal vision.

Why two eyes are better than one: the two views of binocular vision.

Despite centuries of research on the topic, the answer to the question "'Are two eyes significantly better than one, independent of stereopsis?" is still uncertain. In this investigation, steps are taken toward answering the question in a behavioral context. Three sets of experiments are reported in which human binocular and monocular performance are compared in a variety of exteroceptive and visuomotor tasks. In all of the experiments, two eyes facilitated performance. The findings suggest that the binocular system is able to detect the matching information, that is, the concordance, in the monocular optic arrays and to use that information to increase visual efficiency. Furthermore, stereopsis was not found to be important in the performance of visuomotor skills in three dimensions when the subjects were free to move their heads. Thus, the results indicate that an important ecological benefit of binocular frontal vision is having binocular concordance, rather than having binocular disparity.