Usefulness of MRI Slices Parallel to the Optic Chiasma in a Case with Traumatic Optic Nerve Avulsion after a Bear Attack.

Optic nerve avulsion is an exceedingly rare condition. Here, we describe a case of optic nerve avulsion in a 74-year-old man with temporal hemianopia in the contralateral eye after a bear attack. Magnetic resonance imaging (MRI) revealed separation of the optic nerve distal to the optic chiasma, whereas the high signal in diffusion-weighted imaging suggested nerve injury from the left side of the optic chiasma to the left optic tract. MRI slices parallel to the optic chiasma were obtained and used for evaluating the site of optic nerve avulsion and nerve injury, which were responsible for temporal hemianopia in the contralateral eye.

Traumatic Globe Luxation With Chiasmal Avulsion.

BACKGROUND: To describe an unusual case of traumatic globe luxation with optic chiasmal avulsion and review the existing literature on this rare condition for further discussion of mechanisms, diagnosis, and management. METHODS: Case report and review of existing case reports and case series identified through literature search. RESULTS: A 28-year-old woman, with no previous medical history, had left globe luxation and optic chiasm avulsion after being stabbed directly into the left orbit with the use of the stiletto high heel of a shoe. Automated visual field testing detected a temporal hemianopia in the unaffected eye despite normal central visual acuity. Chiasmal avulsion was demonstrated by MRI. CONCLUSIONS: This case suggests that perimetry and MRI should always be considered in traumatic globe luxation to localize the site of injury. Temporal hemianopia in the fellow eye indicates a concomitant chiasmal injury.

Nieve visual / Visual snow

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Isolated bitemporal hemianopsia due to traumatic chiasmal syndrome.

A 20-year-old man presented with complaints of inability to see the outer half of objects and blurred near vision while reading. His complaints began one year ago after a motor vehicle accident that caused cranio-orbital fractures. Ocular examination revealed complete bitemporal hemianopsia and slight exotropia. Central visual acuity was 20/20 in both eyes. Radiologic studies demonstrated fractures in the fronto-ethmoid and sphenoid bones and thinning of the optic chiasm. No hypothalamic-pituitary abnormality was detected. Clinical findings remained unchanged during follow-up. Although rare, blunt head trauma may cause an isolated damage to the chiasmal crossing nerve fibers, resulting in a complete, bitemporal hemianopsia associated with normal visual acuity. Traumatic chismal syndrome should be considered in the differential diagnosis of patients presenting with bitemporal hemianopsia.

[The clinical features and value of macular ganglion cell complex thickness patterns in patients with optic chiasma lesion].

OBJECTIVE: To evaluate patterns of macular retinal ganglion cell complex thickness (mRGCCT) in patients with two types of neurologic lesions in optic chiasm region. METHODS: Retrospective case review study. Visual field test was conducted with automated perimetry (HAAG-STREIT OCTOPUS101 V6.07g Seven-in-One and 2010(HFA Ⅱ750-40220-5.1.1/5.1.1) Carl Zeiss Meditec), and visual field in the central 30 degree region was measured. Three types of thickness mapping including macular retinal thickness (MRT), macular ganglion cell complex thickness (mGCCT) and peripapillary retinal nerve fiber layer (pRNFL) were recorded with TOPCON 3D-OCT 2000 spectral domain OCT. The results of OCT were compared with visual field. RESULTS: Sixteen cases were included in this study, male 10 cases, female 6 cases. Age 5 to 77 years (average 48.2). Neurologic lesions including pituitary tumor (9 cases), craniopharyngioma (3 cases), optic canal dysplasia in optic chiasm region (1 case), meningioma (1 case), hemangioma (1 case) and aneurysm (1 case). 14 cases have chronic, progressive, long course of disease, OCT showed characteristic perpendicular bisector delimitation, bilateral nasal mGCCT atrophy and corresponding temporal hemianopsia. 2 cases (both were pituitary tumor ) have a chronic, short duration, accelerated attack, visual acuity and visual field rapidly declined, mGCCT is swelling or approach high limit of normal range. In pRNFL thickness map, atrophy of mRNFL in temporal peripapillary and nasal macular region could be observed. CONCLUSIONS: Chronic, progressive, long course of disease, combined with characteristic perpendicular bisector delimitation, bilateral nasal mGCCT atrophy and corresponding temporal hemianopsia is helpful to predict lesion of disease. mGCCT map is of equal importance with visual field test for diagnosis of lesion within optic chiasm. In cases with a chronic, short disease course, and accelerated attack, mGCCT could be swelling, but pRNFL could be thinner in temporal peripapillary and nasal macular region of single or both eyes, and visual field test is thus necessary in these cases.

Blunt forehead trauma and optic canal involvement: finite element analysis of anterior skull base and orbit on causes of vision impairment.

BACKGROUND: Clinical studies report on vision impairment after blunt frontal head trauma. A possible cause is damage to the optic nerve bundle within the optic canal due to microfractures of the anterior skull base leading to indirect traumatic optic neuropathy. METHODS: A finite element study simulating impact forces on the paramedian forehead in different grades was initiated. The set-up consisted of a high-resolution skull model with about 740 000 elements, a blunt impactor and was solved in a transient time-dependent simulation. Individual bone material parameters were calculated for each volume element to increase realism. RESULTS: Results showed stress propagation from the frontal impact towards the optic foramen and the chiasm even at low-force fist-like impacts. Higher impacts produced stress patterns corresponding to typical fracture patterns of the anterior skull base including the optic canal. Transient simulation discerned two stress peaks equalling oscillation. CONCLUSIONS: It can be concluded that even comparatively low stresses and oscillation in the optic foramen may cause micro damage undiscerned by CT or MRI explaining consecutive vision loss. Higher impacts lead to typical comminuted fractures, which may affect the integrity of the optic canal. Finite element simulation can be effectively used in studying head trauma and its clinical consequences.

Non-compressive disorders of the chiasm.

Chiasmal dysfunction produces a characteristic clinical picture, regardless of the mechanism. In most cases a compressive lesion is the cause. In occasional cases, however, no such extrinsic mass is found and other possible etiologies must be explored. In some of these cases, the pathologic process is identifiable with appropriate neuroimaging. For example, inflammation, infiltrative tumors, and radiation necrosis produce intrinsic chiasmal enhancement. Chiasmal ischemia may require specialized magnetic resonance (MR) sequences for diagnosis. Chiasmal hemorrhage, trauma and chiasmal herniation typically produce distinctive changes on noncontrasted imaging. In cases of metabolic insult, either toxic or hereditary, radiographic changes are typically absent. In each of these, the correct diagnosis can usually be made with a combination of clinical and radiographic features.

Hemifield slide from traumatic optic chiasmopathy.

A 56-year-old man suffered a high velocity linear acceleration closed head injury, resulting in skull fractures including bone dehiscence at the planum sphenoidale and tuberculum sellae. After regaining consciousness, he reported blurry vision and episodic diplopia. Visual field testing showed a bitemporal hemianopia. Ocular motility testing uncovered no misalignment. Brain MRI revealed post-traumatic encephalomalacia within the optic chiasm, resulting in the visual field defect and subsequent hemifield slide. Normally, cerebral processing of overlap between the visual fields prevents hemifield slide, which is caused by episodic loss of visual field overlap with subsequent slipping or sliding apart of images.

Isolated complete bitemporal hemianopia in traumatic chiasmal syndrome.

A 29-year-old man presented with a chief complaint of lateral blindness in the left eye at 4 months after an accidental fall. His best corrected visual acuity was 0.7 in the left eye and 1.0 in the right eye. Visual field test showed a complete bitemporal hemianopic defect without any neurologic symptoms. An orbital computed tomography scan with non-enhancement conducted at the time of the visit showed multiple frontal skull fractures and cerebromalacia a small fracture in the sphenoidal boneboth frontal lobes. No radiological abnormalities of the visual pathway were detected. Optical coherence showed reduced thickness in the retinal nerve fiber layer, primarily in the superior and inferior part of the left eye. To our knowledge, a complete bitemporal hemianopia without neurological deficits is extremely rare in traumatic chiasmal syndrome.

Differential retinal origins of separate anatomical channels for pattern and motion vision in rabbit.

The most conspicuous feature of the rabbit retina is the visual streak that extends along the horizontal azimuth from the nasal margin to the temporal limit of the retina. We believe the streak processes movement vision and that the temporal region (area centralis) is responsible for pattern perception. Both anatomical and behavioural experiments were used to test this hypothesis. Behavioural measures of pattern vision in normal and chiasma-sectioned rabbits revealed both to have the same visual acuity. Using OKN as a measure of movement vision, normal rabbits showed both a directional and velocity-tuned response. The chiasma-sectioned rabbits, with only uncrossed fibre projections remaining, showed a total loss of movement detection. The injection of HRP into the vitreal chamber of one eye in normal rabbits revealed extensive uptake throughout the contralateral thalamus. In the ipsilateral thalamus, there was uptake solely from the ipsilateral retinal projection to a restricted wafer of the lateral geniculate nucleus (LGN). The chiasma cut rabbits showed a very different distribution of HRP in the thalamus. The uptake was restricted to a thin wafer of the LGN, with no contralateral uptake. Thus, the thalamic projections from the retinal area centralis were strictly segregated from the thalamic target areas for the visual streak without any overlap. These findings provide strong evidence for separate retinal origins with anatomically separate pathways for pattern and movement vision in the rabbit.

Avaliação da camada de fibras nervosas da retina nas afecções neuroftalmológicas da via óptica anterior / Retinal nerve fiber evaluation in neuro-ophthalmic diseases of the anterior visual pathway

A avaliação da camada de fibras nervosas da retina tem grande importância no diagnóstico e acompanhamento de várias afecções da via óptica anterior. Nesta revisão, discutiremos os principais métodos de análise clínica e instrumental da camada de fibras nervosas da retina e revisamos os principais achados encontrados nas afecções da via óptica anterior incluindo lesões inflamatórias, isquêmicas, tóxicas, hereditárias, compressivas e traumáticas do nervo óptico, as lesões do quiasma óptico, as do trato óptico e aquelas do corpo geniculado lateral.

Retinal nerve fiber evaluation is important in the diagnosis and management of several diseases of the anterior visual pathway. In this report we review the clinical findings and the current techonologies avalilable to analyse the retinal nerve fiber layer. We furthermore review the main findings in several disease of the anterior visual pathways including inflammatory, ischemic, toxics, hereditary, compressive and traumatic optic neuropathies as well as lesion of the optic chiasm, optic tract and lateral geniculate body.

[The neuroophthalmic supplement to the NEI-VFQ: test statistics and validation with a cohort of patients with pre- and postchiasmatic damage]. / Das neuroophthalmologische Supplement des NEI-VFQ: Teststatistische Überprüfung und Validierung an einer Stichprobe prä- und postchiasmatisch geschädigter Patienten.

BACKGROUND: The National Eye Institute Visual Function Questionnaire (NEI-VFQ) is not sufficient to assess vision-related quality of life in patients with vision impairments caused by neuroophthalmic deficits. The neuroophthalmic supplement to the NEI-VFQ is currently only available in an English version. The supplement was translated into German and three items concerning visual field loss were added. MATERIAL AND METHODS: NEI-VFQ and supplement data were collected from 62 pre- and postchiasmatic patients with visual field defects and from 245 healthy reference persons. NEI-VFQ and supplement were psychometrically tested and validated. Relations between visual field variables and vision-related quality of life were assessed. RESULTS: The patient group showed diminished quality of life in 10 NEI-VFQ subscales and in eight supplement items when compared to age-matched healthy controls. Correlations between supplement and visual field diagnostic variables demonstrate moderate relations between visual field loss and deterioration of vision-related quality of life. A Cronbach's α of 0.81 for the supplement can be increased to 0.92 in combination with the NEI-VFQ, the sole application of the NEI-VFQ generates an alpha of 0.93 in this sample. A factor analysis reveals four factors that cover the 13 items capturing the following issues: 'severity/problems due to the visual field defect", "unusual eyelid appearances", "blurry vision/double vision" and "diverse vision of both eyes"; 72 % of the variance can be explained by these four factors. CONCLUSION: The German translation of the neuroophthalmic supplement to the NEI-VFQ captures additional vision-specific problems beyond the sole NEI-VFQ that are often reported by patients with vision impairments after brain damage. Although the relevance of some items can be questioned, nevertheless the supplement qualifies for an enhanced outline of subjective vision impairments that are not included in the previous NEI-VFQ.

Penetration and splitting of the optic apparatus by intrasaccular coils within an anterior communicating artery aneurysm.

Penetration of the optic apparatus by an anterior communicating artery (ACoA) aneurysm is unique. A 43-year-old woman with a history of visual disturbance due to a previous aneurismal rupture underwent surgical neck clipping for a recurred ACoA aneurysm, which had previously been treated using detachable coils. The operation confirmed that the recurred aneurysm and the packed coils had penetrated the chiasm and the right optic nerve (ON), which was distorted and thinned. The aneurismal neck was clipped and the coils were left in place because damage to the optic apparatus by penetration is usually irreversible. As the patient was semicomatous at the former admission due to subarachnoid hemorrhage (SAH), she became aware of the visual disturbance 2 weeks after ictus when she had improved enough to communicate. The visual disturbance was found to have gradually improved at her 1-year follow-up. The absence of visual symptoms before the SAH and gradual visual improvement after coiling, even after recurrence due to coil compaction, were considered more compatible with a chronic compensated compressive, penetrating lesion of the ON.

[Case of traumatic chiasmal syndrome].

BACKGROUND: Traumatic neuropathy of the optic chiasm is a rare finding which occurs after severe blunt head trauma. It is often accompanied by dysfunction of the pituitary gland and hypothalamus and called traumatic chiasmal syndrome. We report a patient with traumatic chiasmal syndrome caused by a severe traffic accident. CASE: A 25 year-old woman was referred for bitemporal visual field defects caused by a traffic accident two months before. Corrected visual acuity was 0.05 in the right eye and 1.2 in the left eye. Bilateral optic atrophy and relative afferent pupillary defect in the right eye were found. Magnetic resonance imaging revealed an enlarged optic chiasm. Computed tomography disclosed many fractures in the skull including the back wall of the sphenoid sinuses. She also suffered from diabetes insipidus and anosmia. CONCLUSION: Traumatic optic neuropathy of the optic chiasm is a rare condition which can be differentiated from neuropathy in the optic canal by considering the patterns of visual field defects and their accompanying signs.

Functional impairments caused by chiasma syndromes prior to and following transsphenoidal pituitary adenoma surgery.

PURPOSE: To describe the functional impairment caused by chiasma syndromes (CS) prior to and following transsphenoidal pituitary adenoma surgery. METHODS: Pertinent data of a successive series of patients operated transsphenoidally for the first time for pituitary adenoma were retrospectively analyzed. The degree of functional impairment caused by the impairment of vision was quantified according to the resulting degree of disability (DOD). A DOD of > or =30 is considered substantial. RESULTS: None of the 197 of 304 (64.9%) patients without preoperative chiasma syndrome (CS) experienced postoperative worsening of their visual acuity or their visual fields. Thus, no change of their vision-related DOD (V-DOD) did occur. One hundred and seven (35.1%) of the patients presented preoperatively with CS. Postoperatively, 42.9% of the CS remitted completely, 38.3% improved, 11.2% remained unchanged, and 7.4% worsened. Accordingly, the median V-DOD improved significantly from 30 (0; 100) to 0 (0; 100). The prevalence of patients with V-DOD > or =30 dropped significantly from 51.4% preoperatively to 16.4% postoperatively. Postoperatively, the median V-DOD improved significantly up to 3 months postoperatively. Thereafter, no further significant changes occurred. However, in patients with preoperative CS, the median V-DOD as well as the prevalence of patients with a V-DOD > or =30 remained postoperatively significantly higher compared to patients without preoperative CS. CONCLUSIONS: Visual impairments due to CS frequently caused substantial DOD preoperatively. Postoperatively, the median degree of V-DOD as well as the prevalence of substantial V-DOD improved significantly. However, in patients with preoperative CS, V-DOD remained postoperatively significantly higher than V-DOD of patients without preoperative CS.

Traumatic disruption of the optic chiasm.

A 27-year-old man developed a persistent bitemporal hemianopia after severe head trauma sustained in a high-speed motor vehicle accident. The initial brain MRI revealed hemorrhagic contusion of the optic chiasm. A brain MRI performed 4 weeks later demonstrated complete chiasmal transection, a phenomenon rarely documented with imaging.