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Aplasia of the optic nerve and disk.

To clarify the nature of aplasia of the optic nerve and disk, a rare congenital anomaly defined as absence of the optic nerve and disk, retinal ganglion cells, and retinal blood vessels, we evaluated all the cases with this designation in the files. Thirteen cases demonstrated that optic nerve aplasia typically occurs uniocularly in an otherwise healthy person. There was no sexual or racial predilection, or any evidence of an inherited factor. We believe typical aplasia of the optic nerve results from abnormal invagination of the ventral fissure and that the multiple associated ocular anomalies may also be attributed in part to this same mechanism. Two cases were atypical: they were bilateral, there was an associated hydrocephalus in one case and a possible familial history in the other, they apparently had a different pathogenesis from the typical cases, and possibly represent an extreme form of hypoplasia of the optic nerve.

Adolescent↗

Ocular manifestations of drug abuse.

Abuse of drugs, including some used clinically and others with no legal or clinical use, can cause ocular injury and disease. Ocular manifestations of drug abuse may be due to the substances themselves, to invasive methods of administration, or to injury suffered during states of altered consciousness. Grouping the drugs into five categories (opiates, marijuana, stimulants, depressants and hallucinogens), the authors describe the pharmacologic, congenital, toxic, infectious, embolic, and psychological ocular manifestations of their abuse.

Acquired Immunodeficiency Syndrome↗

Transcranial Doppler sonography in carotid-cavernous fistulas: analysis of five cases.

Transcranial doppler sonography was performed transorbitally in five patients clinically diagnosed as unilateral carotid-cavernous fistula. Dural arteriovenous malformation related-shunts were detected in all the patients. In the normal eyes, the only doppler signals observed at an insonation depth of 45 to 55 mm were those of the ophthalmic artery. In the affected eyes, abnormal doppler signals with relatively higher flow velocity and lower resistance were observed. In three of the cases, these abnormal signals showed a flow directed anteriorly or away from the cavernous sinus, consistent with changes in the ophthalmic veins caused by the presence of the shunts. In two cases, however, the observed flows were directed posteriorly, the normal direction of these veins. The possible explanations for this discrepancy are discussed in relation with angiographic findings. The use of transcranial doppler might provide a better understanding about hemodynamic changes in carotid cavernous fistulas.

Aged↗

Role of visuo-vestibular interaction in pathological ocular oscillation: new model and control system analysis.

Control system engineering is a relatively newer field of engineering which is directly applicable to performance analysis of neuronal networks. Visuo-vestibular interaction (VVI) represents a neuronal control system which has most benefited from such analysis. In this paper, we present a new model of VVI derived from our previously reported model by adding cortical pursuit feedback. Mathematical analysis of abnormal eye oscillations and stability analysis of the VVI system provided us with a plausible hypothesis that the pathological ocular oscillations seen in oculopalatal myoclonus and see-saw nystagmus are indeed due to an unstable VVI control system. The former is due to degeneration of the inferior olivary nucleus resulting in loss of cerebellar learning effects, while the latter is due to disruption of the pathway conveying retinal error signals.

Animals↗

Variable phenotype related to a novel PAX 6 mutation (IVS4+5G>C) in a family presenting congenital nystagmus and foveal hypoplasia.

PURPOSE: Several ocular defects have been identified as a consequence of the PAX6 gene mutations. With regard to the implication of this gene in unusual phenotypes, we report a family presenting with congenital nystagmus, foveal hypoplasia, and iris hypoplasia or atypical coloboma. DESIGN: Observational case report. METHODS: The entire transcribed region of the PAX6 gene was submitted to mutation search at the DNA and mRNA levels in five affected members of a French family in test with 82 normal subjects. RESULTS: A novel heterozygous PAX6 gene splice mutation (IVS4 + 5G>C) was identified. The mutation is located in IVS4 within the consensus donor splice site. A mutant mRNA lacking exon 4 as the sole defect was evidenced. The resultant protein was predicted to contain a cryptic ATG initiation codon in exon 3 and a slightly altered paired-domain in an open reading frame extended by 13 amino acids. CONCLUSIONS: The association of anterior segment anomalies and foveal hypoplasia with one of the slightest alterations of the PAX6 protein described to date confirms the association of variant phenotypes with hypomorphic alleles. Mutation screening of the PAX6 gene could be useful in elucidating the origin of complex ocular malformations.

Adult↗

Structural neural networks subserving oculomotor function in first-episode schizophrenia.

BACKGROUND: Smooth pursuit and antisaccade abnormalities are well documented in schizophrenia, but their neuropathological correlates remain unclear. METHODS: In this study, we used statistical parametric mapping to investigate the relationship between oculomotor abnormalities and brain structure in a sample of first-episode schizophrenia patients (n = 27). In addition to conventional volumetric magnetic resonance imaging, we also used magnetization transfer ratio, a technique that allows more precise tissue characterization. RESULTS: We found that smooth pursuit abnormalities were associated with reduced magnetization transfer ratio in several regions, predominantly in the right prefrontal cortex. Antisaccade errors correlated with gray matter volume in the right medial superior frontal cortex as measured by conventional magnetic resonance imaging but not with magnetization transfer ratio. CONCLUSIONS: These preliminary results demonstrate that specific structural abnormalities are associated with abnormal eye movements in schizophrenia.

Adolescent↗

Modifications of the retina neuronal populations of the heterozygous mutant small eye mouse, the Sey(Dey).

We analyzed the modifications of the retinal neurons in a heterozygous mutant small eye mouse, the Sey(Dey). This mouse presents a mutation in chromosome 2 which affects the gene Pax6 and other nearby genes, such as the Wt1 gene and the gene of the Reticulocalbin. The eyes of these animals do not have lenses and their retinas present important morphological alterations: in the anterior portion they are joined to the cornea, they are found detached from the pigment epithelium, they present folds that form rosettes in some zones and alteration of the lamination can be observed. The partial loss of the genes affected does not prevent the formation of the different layers of the retina, but does affect its thickness, principally of the plexiform layers; moreover, the internal limiting membrane is found disorganized. All the neuronal populations are present in the retina of these animals and express the same neurochemical markers as the control animals, but the number of Pax6(+) cells is notably reduced. In these retinas a marked disorganization of the distribution of the dendrites and axons is observed and a notable reduction in the axons of ganglion cells. These results suggest that, although it does not appear determinant in the differentiation of the distinct neuronal types of the retina, the partial lack of genes of the heterozygotes +/Sey(Dey) provokes important morphological and neurochemical modifications in the cytoarchitecture of the retina.

Animals↗

Otolaryngologic manifestations of PHACE syndrome.

Two case reports of PHACE syndrome (posterior fossa malformations (P), hemangiomas (H), arterial anomalies (A), coarctation of the aorta and cardiac defects (C), and eye abnormalities (E)) are presented. Clinical characteristics consisted of cutaneous and airway hemangiomas, aortic coarctation, and left superior vena cava in one child and cutaneous and airway hemangiomas, sternal clefting, and supraumbilical raphe in the other child. Treatment modalities included systemic and intralesional steroids for cutaneous and airway hemangiomas, submucosal resection and laryngotracheal reconstruction for airway hemangiomas, repair of aortic coarctation, and laser treatment of cutaneous hemangiomas. PHACE syndrome poses a significant potential for airway compromise from hemangiomas, which may require multimodality treatment.

Abnormalities, Multiple↗

Ophthalmic manifestations of Wolf-Hirschhorn syndrome.

PURPOSE: Wolf-Hirschhorn syndrome is caused by partial deletion of the short arm of chromosome 4 (4p-). Common features include developmental delay, microcephaly, seizures, craniofacial anomalies, mental retardation, and cardiac defects. This article further describes the ocular manifestations of this rare disorder. METHODS: Charts of patients with 4p- from the University of Arkansas (n = 3) and the University of Minnesota (n = 7) were reviewed. Diagnosis was made by a geneticist and was confirmed by karyotype. Cytogenetic reports were available for review in eight patients. RESULTS: Ten patients (six females and four males) aged 4 months to 11 years were included. Ophthalmic findings included exodeviation (9/10), nasolacrimal obstruction (6/10), shallow orbits (3/10), epicanthal folds (3/10), foveal hypoplasia (3/10), upper lid coloboma (2/10), optic disk anomalies (2/10), downslanting palpebral fissures (2/10), microcornea (2/10), hypertelorism (1/10), nystagmus (1/10), and chorioretinal coloboma (1/10). Eight patients with 4p- had break points ranging from band 4p14 to 4p16.3. CONCLUSIONS: This study expands on previous reports of the ophthalmic phenotype in 4p- and includes the additional findings of foveal hypoplasia, nystagmus, shallow orbits, epicanthal folds, and upper lid colobomas. Ophthalmic findings in 4p- are variable, likely related to the size of the deletion.

Abnormalities, Multiple↗