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.

Even though retinal images of objects change their locations following each eye movement, we perceive a stable and continuous world. One possible mechanism by which the brain achieves such visual stability is to construct a craniotopic coordinate by integrating retinal and extraretinal information. There have been several proposals on how this may be done, including eye-position modulation (gain fields) of retinotopic receptive fields (RFs) and craniotopic RFs. In the present study, we investigated coordinate systems used by RFs in the lateral intraparietal (LIP) cortex and frontal eye fields (FEF) and compared the two areas. We mapped the two-dimensional RFs of neurons in detail under two eye fixations and analyzed how the RF of a given neuron changes with eye position to determine its coordinate representation. The same recording and analysis procedures were applied to the two brain areas. We found that, in both areas, RFs were distributed from retinotopic to craniotopic representations. There was no significant difference between the distributions in the LIP and FEF. Only a small fraction of neurons was fully craniotopic, whereas most neurons were between the retinotopic and craniotopic representations. The distributions were strongly biased toward the retinotopic side but with significant craniotopic shifts. These results suggest that there is only weak evidence for craniotopic RFs in the LIP and FEF, and that transformation from retinotopic to craniotopic coordinates in these areas must rely on other factors such as gain fields.
Animals ; Macaca ; Visual Fields ; Frontal Lobe/physiology* ; Eye Movements ; Brain

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. Methods: 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. Results: 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. Conclusion 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.
visual fields ; retrospective studies ; Philippines ; pituitary neoplasm ; visual acuity

OBJECTIVES: To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury. METHODS: Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential (VEP) and multifocal visual evolved potential (mfVEP) measurements, craniocerebral CT/MRI, and retinal optical coherence tomography (OCT) were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively. RESULTS: The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder (RAPD) and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway. CONCLUSIONS Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.
Humans ; Optic Chiasm/pathology* ; Visual Pathways/pathology* ; Visual Fields ; Evoked Potentials, Visual ; Random Amplified Polymorphic DNA Technique ; Hemianopsia/complications* ; Vision Disorders/pathology* ; Optic Nerve Injuries/diagnostic imaging* ; Brain Injuries, Traumatic/diagnostic imaging*

Introduction: To determine the structure-function correlations of glaucoma in Filipinos using the average peripapillary retinal nerve fiber layer (RNFL) thickness and rim area (RA) of the spectral-domain optical coherence tomography (SD-OCT) and mean defect (MD), pattern standard deviation (PSD), and visual field (VF) clusters of standard automated perimetry (SAP) Methods: Consecutive tests consisting of SD-OCT, SAP, and disc photos were reviewed and selected based on abnormalities in VFs or OCTs or both. Each set of tests was classified as to VF defect type and severity. Mean threshold of VF clusters, MD, and PSD were correlated with average and sectoral RNFL thicknesses and RA. Results: One hundred eighty-six (168) eyes of 121 patients with mean age of 60.2 ± 14.7 years had an average MD, PSD, RNFL thickness, RA of -9.5 ± 8.5 dB, 5.4 ± 3.3 dB, 75.9 ± 15.9 μm, and 0.9 ± 0.4 mm2, respectively. Among VF tests, 23.1% were normal, 16.5% had early, 9.1% moderate, 12.4% advanced, and 8.3% severe glaucoma damage. Most common VF defect types were central islands, combined, and paracentral (16.5%, 14.4%, and 12.2%, respectively). The most commonly affected RNFL segments were inferior, followed by superior, and combined superior and inferior (51.2%, 47.1, and 34%, respectively). Among the OCT parameters, RNFL thickness and RA were strongly correlated (p<0.0001). Between the VF and OCT parameters, the strongest correlation was between the clusters of superior VF defects and the 6-8 o’clock RNFL thinning, followed by the inferior VF defects and the 12-1 o’clock RNFL thinning. Inferior RNFL thinning was strongly correlated with MD and PSD. Conclusion Among Filipino glaucomatous eyes monitored with SD-OCT and SAP, correlation was strongest between the superior VF defects and the infero-temporal RNFL thinning.
Visual Fields ; Tomography, Optical Coherence ; Glaucoma

Active exploratory behaviors have often been associated with theta oscillations in rodents, while theta oscillations during active exploration in non-human primates are still not well understood. We recorded neural activities in the frontal eye field (FEF) and V4 simultaneously when monkeys performed a free-gaze visual search task. Saccades were strongly phase-locked to theta oscillations of V4 and FEF local field potentials, and the phase-locking was dependent on saccade direction. The spiking probability of V4 and FEF units was significantly modulated by the theta phase in addition to the time-locked modulation associated with the evoked response. V4 and FEF units showed significantly stronger responses following saccades initiated at their preferred phases. Granger causality and ridge regression analysis showed modulatory effects of theta oscillations on saccade timing. Together, our study suggests phase-locking of saccades to the theta modulation of neural activity in visual and oculomotor cortical areas, in addition to the theta phase locking caused by saccade-triggered responses.
Animals ; Frontal Lobe/physiology* ; Macaca mulatta ; Neurons/physiology* ; Saccades ; Theta Rhythm ; Visual Fields

PURPOSE: To investigate correlations between macular retinal ganglion cell (RGC) layer thickness and best-corrected visual acuity (BCVA) and visual field parameters in patients with bilateral temporal optic atrophy.METHODS: Thirty eyes of 15 patients with bilateral temporal optic atrophy and 30 eyes of 15 normal subjects that were age- and sex-matched were included in the study. We measured the thicknesses of the RGC layers of posterior poles using optical coherence tomography volume scanning. The RGC layer was divided into nine zones based on the Early Treatment of Diabetic Retinopathy Study baseline. Possible correlations of the RGC layer with the BCVA and visual field parameters were determined.RESULTS: The RGC layer thickness was significantly thinner in all patients compared to those in the control group (p = 0.001). The RGC layer thicknesses in the inner superior, inner temporal, inner inferior, and inner nasal areas were significantly correlated with the BCVA (r = −0.650, r = −0.626, r = −0.616, and r = −0.636, respectively; p = 0.000). The RGC layer thicknesses in the outer superior, outer temporal, outer inferior, and outer nasal areas were significantly correlated with the mean deviation of the visual field test (r = 0.470, r = 0.349, r = 0.496, and r = 0.469, respectively; p < 0.05).CONCLUSIONS: In patients with bilateral temporal optic atrophy, the RGC layer thickness in the medial region was correlated with the BCVA, and the RGC layer thickness in the lateral region was correlated with the mean deviation of the visual field test.
Diabetic Retinopathy ; Humans ; Optic Atrophy ; Retinal Ganglion Cells ; Retinaldehyde ; Tomography, Optical Coherence ; Vision Disorders ; Visual Acuity ; Visual Field Tests ; Visual Fields

PURPOSE: To investigate the effect of a visual field (VF) test on intraocular pressure (IOP) and relevant parameters in a normal group and an open-angle glaucoma group, and to determine the appropriate time of IOP measurements.METHODS: The IOP was measured by a rebound tonometer before and after a VF test for the normal, normal-tension glaucoma, and high-tension glaucoma groups, and IOP differences after the VF tests were compared among groups. Parameters including age, sex, axial length, central corneal thickness, IOP before the VF test, the VF index, mean deviation, VF test duration, and usage of IOP lowering medications were investigated, and the correlations of these parameters with IOP changes after VF tests were determined using linear regression analyses.RESULTS: A total of 232 participants (232 eyes) included 55 normal subjects, 131 normal-tension glaucoma patients, and 46 high-tension glaucoma patients. The IOP differences after VF tests were not statistically significant in the normal and high-tension glaucoma groups, and the difference was 0.31 mmHg in the normal-tension glaucoma group (p = 0.013). Multivariate regression analyses revealed that axial length (p = 0.005) and IOP before the VF test (p < 0.001) were relevant factors in the total number of patients, and the axial length (p = 0.017), IOP before the VF test (p = 0.001), and duration (p = 0.029) were found to be significantly associated with IOP differences in the normal-tension glaucoma group.CONCLUSIONS: The IOP changes after VF tests using the rebound tonometer were significant in the normal-tension glaucoma group, but were within an acceptable range. The IOP value measured after a VF test is clinically valid in clinical practice.
Glaucoma ; Glaucoma, Open-Angle ; Humans ; Intraocular Pressure ; Linear Models ; Low Tension Glaucoma ; Visual Field Tests ; Visual Fields

PURPOSE: To report a case of non-glaucomatous retinal nerve fiber layer (RNFL) defect associated with paravascular inner retinal defect (PIRD) in a patient with idiopathic epiretinal membrane (ERM).CASE SUMMARY: A 70-year-old male who was diagnosed with ERM in his right eye and pseudoexfoliative glaucoma in his left eye visited our clinic. His intraocular pressure was 14 mmHg in both eyes while using topical hypotensive medications in both eyes. His right eye showed no glaucomatous change of the optic disc head, and also no glaucomatous visual field defect on standard automated perimetry. Red-free fundus photography and swept-source optical coherence tomography showed an ERM and wedge-shaped RNFL defect starting from the PIRD, not the optic disc head. He was diagnosed with non-glaucomatous RNFL defect in the right eye and was told to stop using topical hypotensive medication for the right eye. After 2 years of discontinuing the medication, the IOP was within the normal range, the RNFL defect showed no progression, and the visual field remained stationary.CONCLUSIONS: A non-glaucomatous RNFL defect can develop in association with PIRD in patients with idiopathic ERM. Examinations for PIRD as well as evaluation of the optic disc head are therefore necessary in patients with ERM and RNFL defect.
Aged ; Epiretinal Membrane ; Glaucoma ; Head ; Humans ; Intraocular Pressure ; Male ; Nerve Fibers ; Photography ; Reference Values ; Retinaldehyde ; Tomography, Optical Coherence ; Visual Field Tests ; Visual Fields

visual field (VF) changes were compared among the groups.RESULTS: Three groups were included: stable, progressive peripapillary RNFL thinning without macular GCIPL involvement, and progressive thinning of both the peripapillary RNFL and macular GCIPL. The third group, those with progressive peripapillary RNFL and macular GCIPL thinning, showed more progressive peripapillary RNFL thinning in the inferotemporal area and VF progression in the parafoveal area. Conversely, the 12 and 6 o'clock areas were the most common locations of progressive peripapillary RNFL thinning in the group without macular GCIPL involvement.CONCLUSIONS: Structural progression patterns of glaucoma can be categorized into three groups. The location of progressive peripapillary RNFL thinning is associated with progressive macular GCIPL thinning and pattern of VF changes in the affected area. Our results indicate that the use of only macular GCIPL analysis is inadequate for analyzing the structural progression of glaucoma.]]>
Cluster Analysis ; Ganglion Cysts ; Glaucoma ; Glaucoma, Open-Angle ; Machine Learning ; Nerve Fibers ; Retinaldehyde ; Tomography, Optical Coherence ; Visual Fields