Abstract
Purpose: :
To compare visual acuity with latencies and amplitudes of the visual evoked potential in patients presenting in a university eye clinic with reduced visual acuity of unknown cause.
Methods: :
One hundred and eighy-two successive patients examined in a university eye clinic with reduced visual acuity of unknown cause were referred for diagnostic recording of visual evoked potentials (VEP). Pattern VEP was performed on both eyes according to the ISCEV standards using monocular stimulation with three successive among the six checkerboard sizes: 9.5’, 19’, 39’, 1 17’, and 2 34’. The latency (msec) and the amplitude (microV) of the signal obtained with the mid occipital electrode (Oz) and a checkerboard size of 39’ were correlated to visual acuity in 323 eyes where visual acuity was above FC and could be represented as a decimal value.
Results: :
Visual acuity ranged between 0.01 and 1.25. There was found no significant correlation between visual acuity and neither the amplitude (p=0.91) nor the latency (p=0.95) of the VEP.
Conclusions: :
Neither the latencies nor the amplitudes of the visual evoked potential (VEP) correlate with visual acuity in patients with reduced visual acuity of unknown cause. This discrepancy may be due to functional visual loss in a substantial number of these patients.
Keywords: electrophysiology: clinical