Eye And Brain[JOURNAL]
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183 papers
Cortical inputs to the middle temporal visual area in New World owl monkeys.
Cerkevich CM, Collins CE, Kaas JH
Eye Brain · 2014 Dec · PMID 25620872 · Full text
We made eight retrograde tracer injections into the middle temporal visual area (MT) of three New World owl monkeys (). These injections were placed across the representation of the retina in MT to allow us to compare th...
We made eight retrograde tracer injections into the middle temporal visual area (MT) of three New World owl monkeys (). These injections were placed across the representation of the retina in MT to allow us to compare the locations of labeled cells in other areas in order to provide evidence for any retinotopic organization in those areas. Four regions projected to MT: 1) early visual areas, including V1, V2, V3, the dorsolateral visual area, and the dorsomedial visual area, provided topographically organized inputs to MT; 2) all areas in the MT complex (the middle temporal crescent, the middle superior temporal area, and the fundal areas of the superior temporal sulcus) projected to MT. Somewhat variably across injections, neurons were labeled in other parts of the temporal lobe; 3) regions in the location of the medial visual area, the posterior parietal cortex, and the lateral sulcus provided other inputs to MT; 4) finally, projections from the frontal eye field, frontal visual field, and prefrontal cortex were also labeled by our injections. These results further establish the sources of input to MT, and provide direct evidence within and across cases for retinotopic patterns of projections from early visual areas to MT.
How bees distinguish black from white.
Horridge A
Eye Brain · 2014 · PMID 28539787 · Full text
Bee eyes have photoreceptors for ultraviolet, green, and blue wavelengths that are excited by reflected white but not by black. With ultraviolet reflections excluded by the apparatus, bees can learn to distinguish betwee...
Bee eyes have photoreceptors for ultraviolet, green, and blue wavelengths that are excited by reflected white but not by black. With ultraviolet reflections excluded by the apparatus, bees can learn to distinguish between black, gray, and white, but theories of color vision are clearly of no help in explaining how they succeed. Human vision sidesteps the issue by constructing black and white in the brain. Bees have quite different and accessible mechanisms. As revealed by extensive tests of trained bees, bees learned two strong signals displayed on either target. The first input was the position and a measure of the green receptor modulation at the vertical edges of a black area, which included a measure of the angular width between the edges of black. They also learned the average position and total amount of blue reflected from white areas. These two inputs were sufficient to help decide which of two targets held the reward of sugar solution, but the bees cared nothing for the black or white as colors, or the direction of contrast at black/white edges. These findings provide a small step toward understanding, modeling, and implementing in silicon the anti-intuitive visual system of the honeybee, in feeding behavior.
Orientation domain diversity in macaque area V2.
Ramsden BM, Hung CP, Roe AW
Eye Brain · 2014 · PMID 28539790 · Full text
Single orientation domains in primary (V1) and second (V2) visual cortical areas are known to encode the orientation of visual contours. However, the visual world contains multiple and complex contour types. How do these...
Single orientation domains in primary (V1) and second (V2) visual cortical areas are known to encode the orientation of visual contours. However, the visual world contains multiple and complex contour types. How do these domains handle such complexity? Using optical imaging methods, we have examined orientation response to two types of contours: real (luminance-defined) and illusory (inferred). We find that, unlike area V1, there are multiple types of orientation domain in V2. These include "real only" domains, "higher-order" domains (which respond to an orientation whether real or illusory), and other domains with nonmatching real/illusory orientation preference. We suggest that this plurality of orientation domains in V2 enables the complexities of local and global contour extraction.
Mutual information of local field potentials distinguishes area-V2 stripe compartments.
Parajuli A, Eriksson A, Felleman DJ
Eye Brain · 2014 · PMID 28539789 · Full text
PURPOSE: Determining how information is represented by populations of neurons in different cortical areas is critical to our understanding of the brain mechanisms of visual perception. Recently, information-theoretical a...
PURPOSE: Determining how information is represented by populations of neurons in different cortical areas is critical to our understanding of the brain mechanisms of visual perception. Recently, information-theoretical approaches have been applied to the analysis of spike trains of multiple neurons. However, other neurophysiological signals, such as local field potentials (LFPs), offer a different source of information worthy of investigating in this way. In this study, we investigate how the modular organization of area V2 of macaque monkeys impacts the information represented in LFPs. MATERIALS AND METHODS: LFPs were recorded from a 32-channel microelectrode array implanted in area V2 of an anesthetized macaque monkey. The electrode positions were recovered in histological tissue stained for cytochrome oxidase (CO) to reveal the modular organization of V2. Visual stimuli consisted of a variety of moving gratings that differed in orientation, direction, spatial frequency, and chromatic content. RESULTS: LFPs were separated into different frequency bands for analysis of mutual information as a function of stimulus type and CO-stripe location. High-γ-band LFPs revealed the highest information content across the electrode array. The distributions of total mutual information as well as mutual information due to correlations varied greatly by CO stripe. This analysis indicates that local correlations within each CO stripe generally reduce mutual information, whereas correlations between stripes greatly increase mutual information. CONCLUSION: The decomposition mutual information based on the power of different frequency bands of LFPs provides new insight into the impact of modular architecture on population coding in area V2. Unlike other cortical areas, such as V1, where mutual information based on LFP correlations is largely determined by cortical separation, mutual information in V2 is also fundamentally determined by the CO-stripe architecture.
Very-long-range disynaptic V1 connections through layer 6 pyramidal neurons revealed by transneuronal tracing with rabies virus.
Liu YJ, Arreola M, Coleman CM … +1 more , Lyon DC
Eye Brain · 2014 · PMID 28539788 · Full text
Neurons in primary visual cortex (V1) integrate across the representation of the visual field through networks of long-range projecting pyramidal neurons. These projections, which originate from within V1 and through fee...
Neurons in primary visual cortex (V1) integrate across the representation of the visual field through networks of long-range projecting pyramidal neurons. These projections, which originate from within V1 and through feedback from higher visual areas, are likely to play a key role in such visual processes as low contrast facilitation and extraclassical surround suppression. The extent of the visual field representation covered by feedback is generally much larger than that covered through monosynaptic horizontal connections within V1, and, although it may be possible that multisynaptic horizontal connections across V1 could also lead to more widespread spatial integration, nothing is known regarding such circuits. In this study, we used injections of the CVS-11 strain of rabies virus to examine disynaptic long-range horizontal connections within macaque monkey V1. Injections were made around the representation of 5° eccentricity in the lower visual field. Along the opercular surface of V1, we found that the majority of connected neurons extended up to 8 mm in most layers, consistent with twice the typically reported distances of monosynaptic connections. In addition, mainly in layer 6, a steady presence of connected neurons within V1 was observed up to 16 mm away. A relatively high percentage of these connected neurons had large-diameter somata characteristic of Meynert cells, which are known to project as far as 8 mm individually. Several neurons, predominantly in layer 6, were also found deep within the calcarine sulcus, reaching as far as 20° of eccentricity, based on estimates, and extending well into the upper visual field representation. Thus, our anatomical results provide evidence for a wide-ranging disynaptic circuit within V1, mediated largely through layer 6, that accounts for integration across a large region of the visual field.
Anisotropy of ongoing neural activity in the primate visual cortex.
Maier A, Cox MA, Dougherty K … +2 more , Moore B, Leopold DA
Eye Brain · 2014 · PMID 28539791 · Full text
The mammalian neocortex features distinct anatomical variation in its tangential and radial extents. This review consolidates previously published findings from our group in order to compare and contrast the spatial prof...
The mammalian neocortex features distinct anatomical variation in its tangential and radial extents. This review consolidates previously published findings from our group in order to compare and contrast the spatial profile of neural activity coherence across these distinct cortical dimensions. We focus on studies of ongoing local field potential (LFP) data obtained simultaneously from multiple sites in the primary visual cortex in two types of experiments in which electrode contacts were spaced either along the cortical surface or at different laminar positions. These studies demonstrate that across both dimensions the coherence of ongoing LFP fluctuations diminishes as a function of interelectrode distance, although the nature and spatial scale of this falloff is very different. Along the cortical surface, the overall LFP coherence declines gradually and continuously away from a given position. In contrast, across the cortical layers, LFP coherence is discontinuous and compartmentalized as a function of depth. Specifically, regions of high LFP coherence fall into discrete superficial and deep laminar zones, with an abrupt discontinuity between the granular and infragranular layers. This spatial pattern of ongoing LFP coherence is similar when animals are at rest and when they are engaged in a behavioral task. These results point to the existence of partially segregated laminar zones of cortical processing that extend tangentially within the laminar compartments and are thus oriented orthogonal to the cortical columns. We interpret these electrophysiological observations in light of the known anatomical organization of the cortical microcircuit.
Parasitic diseases of zoonotic importance in humans of northeast India, with special reference to ocular involvement.
Das D, Islam S, Bhattacharjee H … +10 more , Deka A, Yambem D, Tahiliani PS, Deka P, Bhattacharyya P, Deka S, Das K, Bharali G, Deka A, Paul R
Eye Brain · 2014 · PMID 28539786 · Full text
Parasitic zoonotic diseases are prevalent in India, including the northeastern states. Proper epidemiological data are lacking from this part of the country on zoonotic parasitic diseases, and newer diseases are emerging...
Parasitic zoonotic diseases are prevalent in India, including the northeastern states. Proper epidemiological data are lacking from this part of the country on zoonotic parasitic diseases, and newer diseases are emerging in the current scenario. Systemic manifestation of such diseases as cysticercosis, paragonimiasis, hydatidosis, and toxoplasmosis are fairly common. The incidence of acquired toxoplasmal infection is showing an increasing trend in association with acquired immunodeficiency syndrome. Among the ocular parasitic diseases, toxoplasmosis, cysticercosis, toxocariasis, dirofilariasis, gnathostomiasis, hydatidosis, amebiasis, giardiasis, etc, are the real problems that are seen in this subset of the population. Therefore, proper coordination between various medical specialities, including veterinary science and other governing bodies, is needed for better and more effective strategic planning to control zoonoses.
Current research on the organization and function of the visual system in primates.
Kaas JH, Balaram P
Eye Brain · 2014 · PMID 26388695 · Full text
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Giant cell arteritis: a review.
Patil P, Karia N, Jain S … +1 more , Dasgupta B
Eye Brain · 2013 · PMID 28539785 · Full text
Giant cell arteritis is the most common vasculitis in Caucasians. Acute visual loss in one or both eyes is by far the most feared and irreversible complication of giant cell arteritis. This article reviews recent guideli...
Giant cell arteritis is the most common vasculitis in Caucasians. Acute visual loss in one or both eyes is by far the most feared and irreversible complication of giant cell arteritis. This article reviews recent guidelines on early recognition of systemic, cranial, and ophthalmic manifestations, and current management and diagnostic strategies and advances in imaging. We share our experience of the fast track pathway and imaging in associated disorders, such as large-vessel vasculitis.
Sensitivity and specificity of the iVue iWellnessExam™ in detecting retinal and optic nerve disorders.
Awad C, Slotnick S, Nath S … +1 more , Sherman J
Eye Brain · 2013 · PMID 28539784 · Full text
BACKGROUND: The purpose of this study was to assess the specificity and sensitivity of the iWellnessExam™ screening protocol available on iVue spectral domain optical coherence tomography (SD-OCT), in a cohort of confirm...
BACKGROUND: The purpose of this study was to assess the specificity and sensitivity of the iWellnessExam™ screening protocol available on iVue spectral domain optical coherence tomography (SD-OCT), in a cohort of confirmed normal subjects and subjects with confirmed disease. METHODS: In total, 126 of 132 confirmed normal subjects and 101 of 107 subjects with confirmed disease were included for analysis. Of the patients with confirmed disease, 67 had retinal disease, 50 had optic nerve disease, and 16 had both retinal and optic nerve pathology. All subjects were screened on the iWellnessExam protocol. Screen shots of the OD, OS, and OU comparison data were obtained and deidentified for reviewer analysis. Based on these data alone, each subject was sorted by a well trained eye care clinician into one of four categories (1, normal; 2, retinal disease; 3, optic nerve disease; 4, retinal and optic nerve disease). RESULTS: Of the confirmed normal subjects, 125 of 126 were correctly identified as normal (specificity 99%). Retinal and/or optic nerve disease was correctly detected in 97 of 101 patients with confirmed disease (category 2, 3, 4), retinal pathology was correctly detected in 64 of 67 patients with retinal disease (category 2, 4), and optic nerve pathology was properly detected in 45 of 50 patients with optic nerve disease (category 3, 4), with a sensitivity of 96%, 95.5%, and 90%, respectively. CONCLUSION: The iWellnessExam offers the health care provider an excellent method for identifying eyes at risk using very reliable technology. High specificity and sensitivity was obtained when reviewed by a well trained eye care clinician. It would be valuable to repeat the study with a novice and/or student clinician reviewing the same data set to ascertain interobserver variability, as well as the impact of clinical experience on accurate referral, based on the screening data.
Comparison of image-assisted versus traditional fundus examination.
Brown K, Sewell JM, Trempe C … +2 more , Peto T, Travison TG
Eye Brain · 2013 · PMID 28539783 · Full text
BACKGROUND: The purpose of this study was to evaluate the ability of image-assisted fundus examination to detect retinal lesions compared with traditional fundus examination. METHODS: Subjects were imaged using a nonmydr...
BACKGROUND: The purpose of this study was to evaluate the ability of image-assisted fundus examination to detect retinal lesions compared with traditional fundus examination. METHODS: Subjects were imaged using a nonmydriatic ultrawide field scanning laser ophthalmoscope. After imaging, subjects underwent both a traditional and an image-assisted fundus examination, in random order. During the image-assisted method, ultrawide field scanning laser ophthalmoscopic images were reviewed in conjunction with a dilated fundus examination. Lesions detected by each method were assigned to one of three regions, ie, optic disc, posterior pole/macula, or mid-to-peripheral retina. Discrepancies between the image-assisted and the traditional examination methods were adjudicated by a retinal ophthalmologist. RESULTS: In total, 170 subjects (339 eyes) were recruited. Agreement between image-assisted and traditional fundus examination varied by lesion type and was excellent for staphyloma (kappa 0.76), fair for suspicious cupping (kappa 0.66), drusen in the posterior pole/macula and mid-to-peripheral retina (0.45, 0.41), retinal pigment epithelial changes in the posterior pole/macula (0.54), peripheral retinal degeneration (0.50), cobblestone (0.69), vitreoretinal interface abnormalities (0.40), and vitreous lesions (0.53). Agreement was poor for hemorrhage in the mid-to-peripheral retina (kappa 0.33), and nevi in the mid-to-peripheral retina (0.34). When the methods disagreed, the results indicated a statistically significant advantage for the image-assisted examination in detecting suspicious cupping ( = 0.04), drusen in the posterior pole/macula and mid-to-peripheral retina ( = 0.004, < 0.001), retinal pigment epithelial changes in the posterior pole/macula ( = 0.04), nevi in the posterior pole/macula and mid-to-peripheral retina ( = 0.01, = 0.007), peripheral retinal degeneration ( < 0.001), hemorrhage in the mid-to-peripheral retina ( = 0.01), and vitreous lesions ( < 0.001). CONCLUSION: Image-assisted fundus examination may enhance detection of retinal lesions compared with traditional fundus examination alone.
Delayed saccadic eye movements in glaucoma.
Kanjee R, Yücel YH, Steinbach MJ … +2 more , González EG, Gupta N
Eye Brain · 2012 · PMID 28539782 · Full text
PURPOSE: To determine whether saccadic eye movements are altered in glaucoma patients. PATIENTS AND METHODS: Sixteen patients with glaucoma and 21 control subjects were prospectively studied. Patients participated in a p...
PURPOSE: To determine whether saccadic eye movements are altered in glaucoma patients. PATIENTS AND METHODS: Sixteen patients with glaucoma and 21 control subjects were prospectively studied. Patients participated in a pro-saccade step task. Saccades were recorded using a noninvasive infrared oculometric device with head-mounted target projection. Medians of saccade reaction time, duration, amplitude, and peak velocity; frequency of express saccades; and percentage of trials with direction error were recorded. -tests were used to compare the glaucoma and age-matched control groups. A correlation analysis of saccade parameters with visual field loss was also performed. RESULTS: Median saccade reaction times were significantly prolonged in glaucoma patients compared with controls (220.9 ± 49.02 ms vs 192.1 ± 31.24 ms; -test: = 0.036). Median duration, median amplitude, and median peak velocity of saccades did not show significant differences between glaucoma and control groups ( > 0.05). Frequency of express saccades was significantly decreased in glaucoma patients compared with controls (1.75 ± 2.32 vs 7.0 ± 6.99; -test: = 0.007). Saccade parameters in glaucoma patients showed no significant correlation with visual field loss. CONCLUSION: Saccadic eye movements are significantly delayed in patients with early, moderate, or advanced glaucoma. Determination of median saccade reaction time may offer a novel functional test to quantify visual function in glaucoma patients. Further studies are needed to determine pathological processes implicated in delayed initiation of saccades, and to assess whether alteration of saccades affects daily activities in glaucoma patients.
Primary headache disorders and neuro-ophthalmologic manifestations.
Schwartz DP, Robbins MS
Eye Brain · 2012 · PMID 28539781 · Full text
Headache is an extraordinarily common complaint presenting to medical practitioners in all arenas and specialties, particularly primary care physicians, neurologists, and ophthalmologists. A wide variety of headache diso...
Headache is an extraordinarily common complaint presenting to medical practitioners in all arenas and specialties, particularly primary care physicians, neurologists, and ophthalmologists. A wide variety of headache disorders may manifest with a myriad of neuro-ophthalmologic symptoms, including orbital pain, disturbances of vision, aura, photophobia, lacrimation, conjunctival injection, ptosis, and other manifestations. The differential diagnosis in these patients is broad and includes both secondary, or symptomatic, and primary headache disorders. Awareness of the headache patterns and associated symptoms of these various disorders is essential to achieve the correct diagnosis. This paper reviews the primary headache disorders that prominently feature neuro-ophthalmologic manifestations, including migraine, the trigeminal autonomic cephalalgias, and hemicrania continua. Migraine variants with prominent neuro-ophthalmologic symptoms including aura without headache, basilar-type migraine, retinal migraine, and ophthalmoplegic migraine are also reviewed. This paper focuses particularly on the symptomatology of these primary headache disorders, but also discusses their epidemiology, clinical features, and treatment.
The role of intrinsically photosensitive retinal ganglion cells in nonimage-forming responses to light.
Warthen DM, Provencio I
Eye Brain · 2012 · PMID 28539780 · Full text
Light exerts many effects on behavior and physiology. These effects can be characterized as either image-forming or nonimage-forming (NIF) visual processes. Image-forming vision refers to the process of detecting objects...
Light exerts many effects on behavior and physiology. These effects can be characterized as either image-forming or nonimage-forming (NIF) visual processes. Image-forming vision refers to the process of detecting objects and organisms in the environment and distinguishing their physical characteristics, such as size, shape, and direction of motion. NIF vision, in contrast, refers to effects of light that are independent of fine spatiotemporal vision. NIF effects are many and varied, ranging from modulation of basal physiology, such as heart rate and body temperature, to changes in higher functions, such as mood and cognitive performance. In mammals, many NIF effects of light are dependent upon the inner retinal photopigment melanopsin and the cells in which melanopsin is expressed, the intrinsically photosensitive retinal ganglion cells (ipRGCs). The ipRGCs project broadly throughout the brain. Many of these projections terminate in areas known to mediate NIF effects, while others terminate in regions whose link to photoreception remains to be established. Additionally, the presence of ipRGC projections to areas of the brain with no known link to photoreception suggests the existence of additional ipRGC-mediated NIF effects. This review summarizes the known NIF effects of light and the role of melanopsin and ipRGCs in driving these effects, with an eye toward stimulating further investigation of the many and varied effects of light on physiology and behavior.
VGLUT1 mRNA and protein expression in the visual system of prosimian galagos (Otolemur garnetti).
Balaram P, Hackett TA, Kaas JH
Eye Brain · 2011 Dec · PMID 22912561 · Full text
The presynaptic storage and release of glutamate, an excitatory neurotransmitter, is modulated by a family of transport proteins known as vesicular glutamate transporters. Vesicular glutamate transporter 1 (VGLUT1) is wi...
The presynaptic storage and release of glutamate, an excitatory neurotransmitter, is modulated by a family of transport proteins known as vesicular glutamate transporters. Vesicular glutamate transporter 1 (VGLUT1) is widely distributed in the central nervous system of most mammalian and nonmammalian species, and regulates the uptake of glutamate into synaptic vesicles as well as the transport of filled glutamatergic vesicles to the terminal membrane during excitatory transmission. In rodents, VGLUT1 mRNA is primarily found in the neocortex, cerebellum, and hippocampus, and the VGLUT1 transport protein is involved in intercortical and corticothalamic projections that remain distinct from projections involving other VGLUT isoforms. With the exception of a few thalamic sensory nuclei, VGLUT1 mRNA is absent from subcortical areas and does not colocalize with other VGLUT mRNAs. VGLUT1 is similarly restricted to a few thalamic association nuclei and does not colocalize with other VGLUT proteins. However, recent work in primates has shown that VGLUT1 mRNA is also found in several subcortical nuclei as well as cortical areas, and that VGLUT1 may overlap with other VGLUT isoforms in glutamatergic projections. In order to expand current knowledge of VGLUT1 distributions in primates and gain insight on glutamatergic transmission in the visual system of primate species, we examined VGLUT1 mRNA and protein distributions in the lateral geniculate nucleus, pulvinar complex, superior colliculus, V1, V2, and the middle temporal area (MT) of prosimian galagos. We found that, similar to other studies in primates, VGLUT1 mRNA and protein are widely distributed in both subcortical and cortical areas. However, glutamatergic projections involving VGLUT1 are largely limited to intrinsic connections within subcortical and cortical areas, as well as the expected intercortical and corticothalamic projections. Additionally, VGLUT1 expression in galagos allowed us to identify laminar subdivisions of the superior colliculus, V1, V2, and MT.
Update on neuromyelitis optica: natural history and management.
Jindahra P, Plant T
Eye Brain · 2012 · PMID 28539779 · Full text
Neuromyelitis optica or Devic disease is an inflammatory disorder of the central nervous system. It is caused by antibodies that attack aquaporin 4 water channels in the cell membrane of astrocytic foot processes at the...
Neuromyelitis optica or Devic disease is an inflammatory disorder of the central nervous system. It is caused by antibodies that attack aquaporin 4 water channels in the cell membrane of astrocytic foot processes at the blood brain barrier. It can involve the optic nerve, the spinal cord and beyond. Here we review its pathophysiology, clinical features, and therapy.
Neuro-ophthalmic sarcoidosis.
Baughman RP, Weiss KL, Golnik KC
Eye Brain · 2012 · PMID 28539778 · Full text
Neuro-ophthalmic disease occurs in about a third of patients with neurosarcoidosis. Optic nerve involvement is the most common manifestation, but other cranial nerves and the optic chiasm can be involved. However, there...
Neuro-ophthalmic disease occurs in about a third of patients with neurosarcoidosis. Optic nerve involvement is the most common manifestation, but other cranial nerves and the optic chiasm can be involved. However, there are several other common diseases that cause optic neuropathy, including multiple sclerosis. The diagnosis of sarcoidosis can often be made based on the multi-organ nature of the disease and ancillary testing. Most patients with neuro-ophthalmic sarcoidosis require systemic therapy. While corticosteroids are usually the first step in therapy, cytotoxic agents such as methotrexate and azathioprine have been useful as steroid-sparing agents for chronic disease. The monoclonal antibodies directed against tumor necrosis factor have been reported as effective in refractory cases of neuro-ophthalmic disease.
Neural mechanisms underlying neurooptometric rehabilitation following traumatic brain injury.
Hudac CM, Kota S, Nedrow JL … +1 more , Molfese DL
Eye Brain · 2012 · PMID 28539777 · Full text
Mild to severe traumatic brain injuries have lasting effects on everyday functioning. Issues relating to sensory problems are often overlooked or not addressed until well after the onset of the injury. In particular, vis...
Mild to severe traumatic brain injuries have lasting effects on everyday functioning. Issues relating to sensory problems are often overlooked or not addressed until well after the onset of the injury. In particular, vision problems related to ambient vision and the magnocellular pathway often result in posttrauma vision syndrome or visual midline shift syndrome. Symptoms from these syndromes are not restricted to the visual domain. Patients commonly experience proprioceptive, kinesthetic, vestibular, cognitive, and language problems. Neurooptometric rehabilitation often entails the use of corrective lenses, prisms, and binasal occlusion to accommodate the unstable magnocellular system. However, little is known regarding the neural mechanisms engaged during neurooptometric rehabilitation, nor how these mechanisms impact other domains. Event-related potentials from noninvasive electrophysiological recordings can be used to assess rehabilitation progress in patients. In this case report, high-density visual event-related potentials were recorded from one patient with posttrauma vision syndrome and secondary visual midline shift syndrome during a pattern reversal task, both with and without prisms. Results indicate that two factors occurring during the end portion of the P148 component (168-256 milliseconds poststimulus onset) map onto two separate neural systems that were engaged with and without neurooptometric rehabilitation. Without prisms, neural sources within somatosensory, language, and executive brain regions engage inefficient magnocellular system processing. However, when corrective prisms were worn, primary visual areas were appropriately engaged. The impact of using early neurooptometric rehabilitation for posttrauma vision syndrome, visual midline shift syndrome, and other similar subtle vision disorders to support neural reorganization is discussed.
The use of SD-OCT in the differential diagnosis of dots, spots and other white retinal lesions.
Zaharova E, Sherman J
Eye Brain · 2011 · PMID 28539776 · Full text
PURPOSE: To demonstrate the utility of a retinal imaging technique using spectral domain optical coherence tomography (SD-OCT) for creating a B-scan layer-by-layer analysis to aid in the differential diagnosis of various...
PURPOSE: To demonstrate the utility of a retinal imaging technique using spectral domain optical coherence tomography (SD-OCT) for creating a B-scan layer-by-layer analysis to aid in the differential diagnosis of various retinal dots, spots, and other white lesions. DESIGN: Review. METHODS: A retrospective review of imaging studies performed with SD-OCT (Topcon, 3DOCT-2000, Oakland, NJ) at SUNY State College of Optometry. RESULTS: B-scan layer-by-layer analysis and unique SD-OCT reflectivity patterns of the following retinal white lesions are reviewed in the order of their retinal layer localization: myelinated nerve fiber layer, cotton wool spot, exudates, edema residues, drusen, fundus albipunctatus, Stargardt disease, Bietti crystalline dystrophy, punctate inner choroidopathy (PIC), presumed ocular histoplasmosis syndrome (POHS), post-photocoagulation chorioretinal scarring, and osseous choristoma. CONCLUSION: The reviewed images demonstrate the utility of SD-OCT in the identification of the unique characteristics of the presented retinal pathologies. SD-OCT is ideal for retinal layer localization of lesions, thus enhancing the differential diagnosis of retinal dots, spots, and other white lesions. Even though true pathognomonic patterns are rare, highly suggestive findings of certain retinal abnormalities often facilitate immediate recognition and diagnosis.
Low-level light therapy of the eye and brain.
Rojas JC, Gonzalez-Lima F
Eye Brain · 2011 · PMID 28539775 · Full text
Low-level light therapy (LLLT) using red to near-infrared light energy has gained attention in recent years as a new scientific approach with therapeutic applications in ophthalmology, neurology, and psychiatry. The ongo...
Low-level light therapy (LLLT) using red to near-infrared light energy has gained attention in recent years as a new scientific approach with therapeutic applications in ophthalmology, neurology, and psychiatry. The ongoing therapeutic revolution spearheaded by LLLT is largely propelled by progress in the basic science fields of photobiology and bioenergetics. This paper describes the mechanisms of action of LLLT at the molecular, cellular, and nervous tissue levels. Photoneuromodulation of cytochrome oxidase activity is the most important primary mechanism of action of LLLT. Cytochrome oxidase is the primary photoacceptor of light in the red to near-infrared region of the electromagnetic spectrum. It is also a key mitochondrial enzyme for cellular bioenergetics, especially for nerve cells in the retina and the brain. Evidence shows that LLLT can secondarily enhance neural metabolism by regulating mitochondrial function, intraneuronal signaling systems, and redox states. Current knowledge about LLLT dosimetry relevant for its hormetic effects on nervous tissue, including noninvasive in vivo retinal and transcranial effects, is also presented. Recent research is reviewed that supports LLLT potential benefits in retinal disease, stroke, neurotrauma, neurodegeneration, and memory and mood disorders. Since mitochondrial dysfunction plays a key role in neurodegeneration, LLLT has potential significant applications against retinal and brain damage by counteracting the consequences of mitochondrial failure. Upon transcranial delivery in vivo, LLLT induces brain metabolic and antioxidant beneficial effects, as measured by increases in cytochrome oxidase and superoxide dismutase activities. Increases in cerebral blood flow and cognitive functions induced by LLLT have also been observed in humans. Importantly, LLLT given at energy densities that exert beneficial effects does not induce adverse effects. This highlights the value of LLLT as a novel paradigm to treat visual, neurological, and psychological conditions, and supports that neuronal energy metabolism could constitute a major target for neurotherapeutics of the eye and brain.
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