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JP Kelly, AH Weiss; Pattern Vep and Visual Field Defects In Children With Optic Pathway Tumors . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1813.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine if a 3-channel VEP montage can predict visual field defects in children with compressive tumors of the visual pathways. Methods: Fifteen children (6 - 15 yrs age) demonstrated suprasellar tumors involving the optic nerve/chiasm, and tracts on MRI (10 chiasmal glioma, 4 craniopharyngioma). All patients (24 eyes) had Goldmann visual fields (GVF) and 5 had additional Humphrey visual fields (HVF). Visual acuity varied from 20/20 to 20/600. The VEP was recorded in 23 eyes from 14 patients. Active electrodes were at O3, Oz, and O4 referenced to Cz. VEP stimuli were check reversal (163', 84', 42', 18') and pattern onset-offset of a white/black and chromatic (L-M and S-cone) sinewave grating (0.5 or 2 c/deg). We examined the major positive peak near 100-160 msec (P100). Results: Perimetry identified hemianopic field defects in 18 of 24 eyes. The remaining 6 eyes had constricted fields by GVF testing. Five patients with both HVF and GVF, showed a hemianopic defect with HVF but a constricted field with GVF. Evidence of a hemispheric VEP asymmetry in the P100 amplitude was found for all eyes. The largest P100 peak was on the midline in 78% of the VEP recordings. Hemispheric asymmetries to check reversal stimuli were identified in 9 eyes, to white/black pattern onset in 14 eyes, and to chromatic pattern onset in 4 eyes. Paradoxical lateralization was evident in 10 eyes of 18 eyes with a hemianopic field defect. The magnitude of the VEP asymmetry in children with visual pathway tumors was limited by variably reduced amplitudes, abnormal waveforms and delayed latencies. Conclusion: The static visual field is more sensitive than the kinetic field in detecting hemianopic field defects in children. The VEP can be useful for the detection of a hemianopic field defect in children with optic pathway tumors, which is improved by using a combination of check reversal and achromatic grating onset stimulation.
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