Multifocal VEP Difference between Early- and Late-onset Strabismus Amblyopia

Purpose: To measure and compare the multifocal visual evoked potentials (mfVEP) difference between early- and late-onset strabismus amblyopia. Methods: Eleven patients with early- and 11 with late-onset strabismus amblyopia with similar range of visual acuity and 11 normal control subjects were recorded with mfVEP. Results: There was no significant difference in latency or amplitude between amblyopic and fellow eyes for the early-onset amblyopic group, whereas in the late-onset amblyopic group, latencies were significantly prolonged and amplitudes were attenuated in the central region of visual field in the amblyopic eye. The responses in the central region of visual field in both amblyopic and fellow eyes of the early-onset amblyopic group were of longer latency and smaller amplitude than normal. In the late-onset group, the responses from amblyopic eye were of increased latency and decreased amplitude in the central visual field compared with normal, but either latency or amplitude from fellow eye did not differ from normal significantly. Conclusions: There is significant difference in the mfVEP characteristics of patients with early- and late-onset strabismus amblyopia.