BACKGROUND AND OBJECTIVE

A parachiasmal lesion is defined as a mass or growth arising from structures around or near the chiasm. Ophthalmologic signs and symptoms may be observed in such condition, such as blurring of vision, visual field defects, and binocular double vision. The primary objective of this study was to describe the presenting ophthalmologic signs and symptoms of parachiasmal lesions among patients consulting at a single institution in the Philippines.

This was a single-center, retrospective, cohort study. Medical records of patients with parachiasmal lesions seen in the Neuro-Ophthalmology clinic of a tertiary Philippine hospital from January 2014 to December 2019 were reviewed. Clinical profile, neuro-ophthalmologic presentation, diagnosis, management, and visual outcomes were summarized by descriptive statistics.

One hundred thirty-three (133) patient records satisfied the study criteria. Most common presenting symptoms were blurring of vision. headache, and loss of vision. Visual acuity at initial visit ranged from 20/20 to no light perception. A relative afferent pupillary defect was present in half of the study population. Almost half presented with normal-looking discs or disc pallor. Bitemporal hemianopia is the most common visual field defect pattern seen in both confrontation and automated visual field testing. Histopathology was significantly associated with visual outcome.

Parachiasmal lesion should be suspected in patients who complain of unilateral blurring of vision, and those who present with normal or pale optic discs. Pituitary adenoma is the most common radiologic and histopathologic diagnosis. Visual outcome after intervention has improved or remained stable in two-thirds of patients; visual recovery is multi-factorial, which is influenced by duration, surgery, and histopathology.

INTRODUCTION: Visual impairment and obesity remain the major public health issues among school-age students in rural areas of China. Obesity is an underlying risk of vision problems. This study aimed to assess the association between visual impairment and body mass index (BMI) among school-age students in rural northwest China. METHODS: This study included 39,385 students from the 4 th to 9 th grade in rural northwest China. From 2018 to 2020, students underwent an assessment of visual acuity (VA) and completed a questionnaire on family demographics, and height and weight measurements. Multiple logistic regression analyses were used to analyse the data. RESULTS: The association between visual impairment and BMI groups was significant in the study population ( P = 0.002) and in different groups (at the different educational, provincial and national levels) ( P < 0.001, separately). Multiple logistic regression analyses revealed a positive relationship between visual impairment and obesity in the study population, including those attending primary school, Han students and the residents of Ningxia autonomous region. CONCLUSION The association between visual impairment and obesity was significant among school-age students in rural northwest China. There should be implementation of policies to address the problem about visual impairment and obesity among school-age students in rural areas.
Humans ; China/epidemiology* ; Body Mass Index ; Male ; Female ; Rural Population ; Vision Disorders/complications* ; Child ; Adolescent ; Students ; Surveys and Questionnaires ; Logistic Models ; Obesity/complications* ; Visual Acuity ; Cross-Sectional Studies

Objective:To investigate the potential characteristic manifestations and application value of the Dynamic Visual Acuity Test（DVAT） in vestibular migraine（VM）. Methods:A total of 50 VM patients（case group） and 50 healthy subjects（control group） diagnosed at the Department of Otorhinolaryngology Head and Neck Surgery, First Hospital of Shanxi Medical University between November 1, 2023, and December 31, 2024, were enrolled. The case group underwent DVAT, video head impulse test（vHIT）, caloric test, and Dizziness Handicap Inventory（DHI） assessment, whereas the control group only received DVAT. Group-based analyses were conducted to examine the effect of age on Dynamic Visual Acuity Loss（DVALoss）, as well as the correlations of DVALoss with vestibular function tests and DHI scores. Results:DVALoss in the case group was significantly higher than that in the control group（P<0.001）. In both groups, age was significantly and positively correlated with DVALoss（P<0.001）. Within the case group, DVALoss was strongly and positively correlated with DHI scores（r=0.807, P<0.001）; it was negatively correlated with the vestibulo-ocular reflex（VOR） gain in vHIT, though without clinical significance, and showed no significant association with the caloric test. Age and DVALoss collectively accounted for 71.3% of the variance in DHI scores（R²=0.713）, with age exerting a relatively minor actual impact. Conclusion:DVAT can sensitively identify the core functional impairments of VM. DVALoss, as a direct functional reflection of the pathological mechanism of VM, is strongly correlated with DHI scores. Incorporating DVALoss into standardized assessments may provide an objective basis for the diagnosis and management of VM.
Humans ; Migraine Disorders/diagnosis* ; Visual Acuity ; Case-Control Studies ; Head Impulse Test ; Vestibular Function Tests ; Female ; Male ; Adult ; Vestibular Diseases/physiopathology* ; Middle Aged ; Caloric Tests

OBJECTIVES: To compare the efficacy of toric implantable collamer lens (Toric-ICL) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia correction in patients with moderate to high myopia complicated with astigmatism. METHODS: We retrospectively collected data from 64 patients (aged 18-42 years) with moderate to high myopia complicated with astigmatism (128 eyes) undergoing either Toric-ICL (28 patients/56 eyes) or FS-LASIK (36 patients/72 eyes) at our department between January, 2019 and December, 2020. The changes of uncorrected distance visual acuity (UCVA), spherical equivalent (SE), mean astigmatism correction index (CI), corneal endothelial cell density (ECD) and intraocular pressure (IOP) following the procedures were compared between the two groups. RESULTS: In FS-LASIK group, all the eyes (72/72) achieved an UCVA≥1.0, similar to the rate in Toric-ICL group (55/56 eyes; P=0.2374). The postoperative SE was also comparable between FS-LASIK and Toric-ICL groups [0.43±0.06 D (range: -1.0 to 1.50 D) vs 0.38±0.05 D (range: -0.75 to 1.00 D); P=0.56]. The mean astigmatism CI was significantly higher in FS-LASIK group than in Toric-ICL group (0.8561 vs 0.7176; P<0.0001), and 88.89% of the eyes in FS-LASIK group and 69.64% in Toric-ICL group had postoperative astigmatism ≤0.50 D. No significant changes were observed in postoperative corneal ECD in FS-LASIK group, whereas ECD decreased significantly after the procedure in Toric-ICL group (P=0.0057). The patients undergoing Toric-ICL exhibited no significant changes of postoperative IOP, but the patients receiving FS-LASIK had significantly reduced IOP after the procedure (P<0.001). CONCLUSIONS Although the patients included in Toric-ICL group had higher myopia and astigmatism, Toric-ICL still showed better predictability and efficacy for astigmatic correction in Toric-ICL group. Toric-ICL is an effective and safe equivalent of FS-LASIK for correcting moderate myopia but can be more advantageous for correcting high myopia with astigmatism.
Humans ; Astigmatism/complications* ; Myopia/complications* ; Keratomileusis, Laser In Situ/methods* ; Retrospective Studies ; Adult ; Visual Acuity ; Adolescent ; Young Adult ; Treatment Outcome ; Male ; Lens Implantation, Intraocular/methods* ; Female ; Phakic Intraocular Lenses ; Intraocular Pressure

Neural activities differentiating bodies versus non-body stimuli have been identified in the occipitotemporal cortex of both humans and nonhuman primates. However, the neural mechanisms of coding the similarity of different individuals' bodies of the same species to support their categorical representations remain unclear. Using electroencephalography (EEG) and magnetoencephalography (MEG), we investigated the temporal and spatial characteristics of neural processes shared by different individual body silhouettes of the same species by quantifying the repetition suppression of neural responses to human and animal (chimpanzee, dog, and bird) body silhouettes showing different postures. Our EEG results revealed significant repetition suppression of the amplitudes of early frontal/central activity at 180-220 ms (P2) and late occipitoparietal activity at 220-320 ms (P270) in response to animal (but not human) body silhouettes of the same species. Our MEG results further localized the repetition suppression effect related to animal body silhouettes in the left supramarginal gyrus and left frontal cortex at 200-440 ms after stimulus onset. Our findings suggest two neural processes that are involved in spontaneous categorical representations of animal body silhouettes as a cognitive basis of human-animal interactions.
Humans ; Animals ; Male ; Electroencephalography ; Magnetoencephalography ; Female ; Young Adult ; Adult ; Pattern Recognition, Visual/physiology* ; Brain Mapping ; Photic Stimulation ; Brain/physiology* ; Dogs

Previous studies have found associations between color discrimination deficits and cognitive impairments besides aging. However, investigations into the microstructural pathology of brain white matter (WM) associated with these deficits remain limited. This study aimed to examine the microstructural characteristics of WM in the non-demented population with abnormal color discrimination, utilizing Neurite Orientation Dispersion and Density Imaging (NODDI), and to explore their correlations with cognitive functions and cognition-related plasma biomarkers. The tract-based spatial statistic analysis revealed significant differences in specific brain regions between the abnormal color discrimination group and the healthy controls, characterized by increased isotropic volume fraction and decreased neurite density index and orientation dispersion index. Further analysis of region-of-interest parameters revealed that the isotropic volume fraction in the bilateral anterior thalamic radiation, superior longitudinal fasciculus, cingulum, and forceps minor was significantly correlated with poorer performance on neuropsychological assessments and to varying degrees various cognition-related plasma biomarkers. These findings provide neuroimaging evidence that WM microstructural abnormalities in non-demented individuals with abnormal color discrimination are associated with cognitive dysfunction, potentially serving as early markers for cognitive decline.
Humans ; White Matter/pathology* ; Male ; Female ; Cognitive Dysfunction/physiopathology* ; Middle Aged ; Aged ; Color Perception/physiology* ; Brain/pathology* ; Neuropsychological Tests ; Diffusion Tensor Imaging

The dorsal and ventral visual streams have been considered to play distinct roles in visual processing for action: the dorsal stream is assumed to support real-time actions, while the ventral stream facilitates memory-guided actions. However, recent evidence suggests a more integrated function of these streams. We investigated the neural dynamics and functional connectivity between them during memory-guided actions using intracranial EEG. We tracked neural activity in the inferior parietal lobule in the dorsal stream, and the ventral temporal cortex in the ventral stream as well as the hippocampus during a delayed action task involving object identity and location memory. We found increased alpha power in both streams during the delay, indicating their role in maintaining spatial visual information. In addition, we recorded increased alpha power in the hippocampus during the delay, but only when both object identity and location needed to be remembered. We also recorded an increase in theta band phase synchronization between the inferior parietal lobule and ventral temporal cortex and between the inferior parietal lobule and hippocampus during the encoding and delay. Granger causality analysis indicated dynamic and frequency-specific directional interactions among the inferior parietal lobule, ventral temporal cortex, and hippocampus that varied across task phases. Our study provides unique electrophysiological evidence for close interactions between dorsal and ventral streams, supporting an integrated processing model in which both streams contribute to memory-guided actions.
Humans ; Male ; Female ; Adult ; Young Adult ; Hippocampus/physiology* ; Memory/physiology* ; Parietal Lobe/physiology* ; Temporal Lobe/physiology* ; Visual Perception/physiology* ; Electrocorticography ; Visual Pathways/physiology* ; Electroencephalography

Previous studies have identified two group-level processes, neural representations of interracial between-group difference and intraracial within-group similarity, that contribute to the racial categorization of faces. What remains unclear is how the brain tracks race-related information that varies across different faces as an individual-level neural process involved in race perception. In three studies, we recorded functional MRI signals when Chinese adults performed different tasks on morphed faces in which proportions of pixels contributing to perceived racial identity (Asian vs White) and expression (pain vs neutral) varied independently. We found that, during a pain expression judgment task, tracking other-race and same-race-related information in perceived faces recruited the ventral occipitotemporal cortices and medial prefrontal/anterior temporal cortices, respectively. However, neural tracking of race-related information tended to be weakened during explicit race judgments on perceived faces. During a donation task, the medial prefrontal activity also tracked race-related information that distinguished between two perceived faces for altruistic decision-making and encoded the Euclidean distance between the two faces that predicted decision-making speeds. Our findings revealed task-dependent neural mechanisms underlying the tracking of race-related information during face perception and altruistic decision-making.
Adult ; Female ; Humans ; Male ; Young Adult ; Brain/diagnostic imaging* ; Brain Mapping ; Decision Making/physiology* ; Facial Recognition/physiology* ; Judgment/physiology* ; Magnetic Resonance Imaging ; Photic Stimulation ; Racial Groups ; Social Perception ; East Asian People

The thalamic reticular nucleus (TRN) plays a crucial role in regulating sensory encoding, even at the earliest stages of visual processing, as evidenced by numerous studies. Orientation selectivity, a vital neural response, is essential for detecting objects through edge perception. Here, we demonstrate that somatostatin (SOM)-expressing and parvalbumin (PV)-expressing neurons in the TRN project to the dorsal lateral geniculate nucleus and modulate orientation selectivity and the capacity for visual information processing in the primary visual cortex (V1). These findings show that SOM-positive and PV-positive neurons in the TRN are powerful modulators of visual information encoding in V1, revealing a novel role for this thalamic nucleus in influencing visual processing.
Animals ; Somatostatin/metabolism* ; Parvalbumins/metabolism* ; Neurons/physiology* ; Thalamic Nuclei/physiology* ; Visual Pathways/physiology* ; Mice ; Mice, Inbred C57BL ; Visual Perception/physiology* ; Male ; Mice, Transgenic ; Visual Cortex/physiology* ; Primary Visual Cortex/cytology*

Direct electrical stimulation of the human cortex can produce subjective visual sensations, yet these sensations are unstable. The underlying mechanisms may stem from differences in electrophysiological activity within the distributed network outside the stimulated site. To address this problem, we recruited 69 patients who experienced visual sensations during invasive electrical stimulation while intracranial electroencephalography (iEEG) data were recorded. We found significantly flattened power spectral slopes in distributed regions involving different brain networks and decreased integrated information during elicited visual sensations compared with the non-sensation condition. Further analysis based on minimum information partitions revealed that the reconfigured network interactions primarily involved the inferior frontal cortex, posterior superior temporal sulcus, and temporoparietal junction. The flattened power spectral slope in the inferior frontal gyrus was also correlated with integrated information. Taken together, this study indicates that the altered electrophysiological signatures provide insights into the neural mechanisms underlying subjective visual sensations.
Humans ; Male ; Female ; Adult ; Visual Perception/physiology* ; Electric Stimulation ; Middle Aged ; Young Adult ; Electrocorticography ; Electroencephalography ; Brain Mapping