Retinal Input to Macaque Superior Colliculus Derives from Branching Axons Projecting to the Lateral Geniculate Nucleus.

The superior colliculus receives a direct projection from retinal ganglion cells. In primates, it remains unknown if the same ganglion cells also supply the lateral geniculate nucleus. To address this issue, a double-label experiment was performed in two male macaques.

Revised Diagnosis From Histiocytic Neoplasm to Optic Chiasm Glioblastoma After Genetic Analysis.

A 46-year-old man presented with left eye blurring. Automated visual field testing showed an incongruous right hemianopia, with sparing of the lower temporal quadrant in the right eye. MRI revealed foci of gadolinium enhancement in the optic chiasm and optic tracts.

Permanent transduction of retinal ganglion cells by rAAV2-retro.

Adeno-associated virus (AAV) is widely used as a vector for delivery of gene therapy. Long term therapeutic benefit depends on perpetual expression of the wild-type gene after transduction of host cells by AAV. To address this issue in a mass population of identified single cells, 4 rats received an injection of a 1:1 mixture of rAAV2-retro-hSyn-EGFP and rAAV2-retro-hSyn-mCherry into each superior colliculus.

Postoperative magnetic resonance imaging of the inferior oblique muscle.

No previous imaging study has described the appearance of the inferior oblique muscle after surgery. It is unknown whether findings signifying prior myectomy or recession are recognizable on magnetic resonance (MR) imaging and how they might differ for the two procedures. After myectomy via a temporal approach, the cauterized muscle stump retracts into the medial orbit.

Quotidian Profile of Vergence Angle in Ambulatory Subjects Monitored With Wearable Eye Tracking Glasses.

Purpose: Wearable eye trackers record gaze position as ambulatory subjects navigate their environment. Tobii Pro Glasses 3 were tested to assess their accuracy and precision in the measurement of vergence angle.

Methods: Four subjects wore the eye tracking glasses, with their head stabilized, while fixating at a series of distances corresponding to vergence demands of: 0.

Ambulatory Monitoring With Eye Tracking Glasses to Assess the Severity of Intermittent Exotropia.

Purpose: To explore the utility of eye tracking glasses in patients with intermittent exotropia as a means for quantifying the occurrence of exotropia, defined as the percentage of time that the eyes are misaligned.

Design: Prospective observational study.

Methods: Eye tracking glasses were used to obtain 68 recordings in 44 ambulatory patients with a history of intermittent exotropia.

Decussating axons segregate within the anterior core of the primate optic chiasm.

Background: The axons of ganglion cells in the nasal retina decussate at the optic chiasm. It is unclear why tumours cause more injury to crossing nasal fibres, thereby giving rise to temporal visual field loss in each eye. To address this issue, the course of fibres through the optic chiasm was examined following injection of a different fluorescent tracer into each eye of a monkey.

somatic mosaicism in a patient with bilateral optic nerve sheath meningiomas: illustrative case.

Background: In the past decade, next-generation sequencing has spurred significant progress in the understanding of cytogenetic alterations that occur in meningiomas. Eighty percent of adult meningiomas harbor pathogenic somatic variants involving , , , , , or Somatic variants in associated with meningiomas usually localize to the gene's WD40 domains but are mutually exclusive to germline mutations, which cause a distinctive autosomal dominant syndrome.

Observations: This case involved a 15-year-old girl with bilateral optic nerve sheath meningiomas, diffuse meningiomatosis, and syndromic features, including craniosynostosis, brain anomalies, syndactyly, brachydactyly, epicanthus, and patent ductus arteriosus.

Massive periorbital edema following hematopoietic stem cell transplantation.

Purpose: To describe a case of severe, bilateral periorbital edema after hematopoietic stem cell transplantation.

Observations: A three-year old girl with metastatic neuroblastoma underwent the second of two tandem autologous peripheral blood stem cell transplants, complicated by engraftment syndrome. On post-engraftment day 11, she developed acute onset of severe periorbital edema.

Fundus imaging of retinal ganglion cells transduced by retrograde transport of rAAV2-retro.

Access of adeno-associated virus (AAV) to ganglion cells following intravitreal injection for gene therapy is impeded by the internal limiting membrane of the retina. As an alternative, one could transduce ganglion cells via retrograde transport after virus injection into a retinal target nucleus. It is unknown if recombinant AAV2-retro (rAAV2-retro), a variant of AAV2 developed specifically for retrograde transport, is capable of transducing retinal ganglion cells.

Columnar and Laminar Segregation of Retinal Input to the Primate Superior Colliculus Revealed by Anterograde Tracer Injection Into Each Eye.

Purpose: After the lateral geniculate nucleus, the superior colliculus is the richest target of retinal projections in primates. Hubel et al. used tritium autoradiography to show that axon terminals emanating from one eye form irregular columns in the stratum griseum superficiale.

Dichoptic visual field mapping of suppression in exotropia with homonymous hemianopia.

Background: The purpose of this study was to investigate which portions of the visual scene are perceived by each eye in an exotropic subject with acquired hemianopia. The pattern of suppression is predictable from knowledge of how suppression scotomas are organized in exotropic subjects with intact visual fields.

Methods: Dichoptic perimetry was performed by having a subject wear red/blue goggles while fixating a cross that was either red or blue.

Interocular suppression in primary visual cortex in strabismus: impact of staggering the presentation of stimuli to the eyes.

Diplopia (double vision) in strabismus is prevented by suppression of the image emanating from one eye. In a recent study conducted in two macaques raised with exotropia (an outward ocular deviation) but having normal acuity in each eye, simultaneous display of stimuli to each eye did not induce suppression in V1 neurons. Puzzled by this negative result, we have modified our protocol to display stimuli in a staggered sequence, rather than simultaneously.

Congenital Visual Field Loss from a Schizencephalic Cleft Damaging Meyer's Loop.

A healthy, asymptomatic woman was referred after incidental discovery of a right superior incongruous hemianopia. Magnetic resonance imaging disclosed a schizencephalic cleft passing through Meyer's loop of the left optic radiation. The lesion may have resulted from a focal vascular accident or disruption of cortical neurogenesis during gestation.

Damage to the Superior Retinae After 30 Gy Whole-Brain Radiation.

Purpose: The most common treatment protocol for whole-brain radiation therapy (WBRT) is 30 Gy in 10 fractions. This regimen entails a low risk of radiation retinopathy, with fewer than a dozen reported cases. We describe a case of radiation retinopathy that was confined to the superior retinae.

The Mechanism of Macular Sparing.

Patients with homonymous hemianopia sometimes show preservation of the central visual fields, ranging up to 10°. This phenomenon, known as macular sparing, has sparked perpetual controversy. Two main theories have been offered to explain it.

Interocular Suppression in Primary Visual Cortex in Strabismus.

People with strabismus acquired during childhood do not experience diplopia (double vision). To investigate how perception of the duplicate image is suppressed, we raised two male monkeys with alternating exotropia by disinserting the medial rectus muscle in each eye at age four weeks. Once the animals were mature, they were brought to the laboratory and trained to fixate a small spot while recordings were made in primary visual cortex (V1).

Bilateral Occlusion Reduces the Ocular Deviation in Intermittent Exotropia.

Purpose: The most common form of strabismus, intermittent exotropia, is thought to become manifest when the drive to fuse is overcome by excessive divergent muscle tone. This principle is tested by examining the alignment of the eyes in the absence of vision. We compare the ocular deviation in patients with intermittent exotropia under conditions of monocular versus binocular occlusion.

Wilbrand's Knee: To Be or Not to Be a Knee?

Wilbrand's knee of the optic chiasm refers to crossing fibers from one optic nerve that stray for a short distance into the opposite optic nerve before joining the optic tract. This loop of aberrant axons, although small, has generated much controversy. In a previous study, labeling of the optic pathway in normal monkeys with a radioactive tracer revealed no Wilbrand's knee.

Long-term labeling of microelectrode tracks with fluorescent latex microspheres.

Background: After physiological recordings are performed in behaving animals, it is valuable to identify microelectrode tracks in histological sections so that neuronal responses can be correlated with brain anatomy. However, no good method currently exists for long-term labeling, so that microelectrode tracks can be recovered months or even years after recording sessions.

New Method: Penetrations were made into the brains of mice with microelectrodes coated with fluorescent dyes packaged into 0.

Saccade Strategy in Alternating Exotropia.

Patient with exotropia frequently alternate fixation, looking at something with one eye and then switching their attention to acquire a new target with the other eye. Which eye informs the brain about the location of the new target? To address this issue, we presented targets dichoptically to 16 exotropes that were visible to the fixating eye, the deviated eye, or to both eyes. We then compared the subjects' choice of eye for target acquisition with the organization of their suppression scotomas.

Vertical Optokinetic Stimulation Induces Diagonal Eye Movements in Patients with Idiopathic Infantile Nystagmus.

Purpose: In patients with early ocular misalignment and nystagmus, vertical optokinetic stimulation reportedly increases the horizontal component of the nystagmus present during fixation, resulting in diagonal eye movements. We tested patients with infantile nystagmus syndrome but normal ocular alignment to determine if this crosstalk depends on strabismus.

Methods: Eye movements were recorded in seven patients with infantile nystagmus.

Papilledema from gain-of-function mutations in the STAT3 gene.

Background: Signal Transducer and Activator of Transcription 3 (STAT3) gain-of-function germline mutations are associated with diverse clinical manifestations, including autoimmune cytopenia, lymphadenopathy, immunodeficiency, endocrinopathy, and enteropathy. We describe a new feature: raised intracranial pressure with papilledema.

Materials And Methods: Report of two cases.