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Visual evoked potential testing items depend on stimuli and recording parameters. There is great variation in flash visual evoked potential (FVEP), while the pattern visual evoked potential (PVEP) is stable. The later is taken as the main objective assessment of visual function indicators in clinical. Only when PVEP cannot be recorded or the waves are hard to be recognized, the FVEP will be a reference indicator. There is less clinical meaning to do FVEP testing alone. Recommended visual evoked potential and electroretinogram in combination will be more comprehensive response visual function.If it is necessary, electrooculogram, multifocal electroretinogram, pattern electroretinogram should apply to test together in some case. Multifocal visual evoked potential (mfVEP) were developed to record local field response, such as the early field change in glaucoma. The mfVEP is not a small version of the conventional visual evoked potential, since the generated source in both is different. The waves of mfVEP are related to the stimulation (spatial, temporary and contrast), recording channel (single, double or four), and method for signal extracting and signal nose ration. It is a potential objective assessment method for retinal ganglion cell or optic nerve and still needs further improvement. There will be variable and fluctuation in any visual electrophysiological testing results, the explanation for the results should be relay on complains, symptom, signs and other laboratory examination results.
6.7 Electro-ophthalmodiagnosis (Part of: 6 Clinical examination methods)