Assessment of visual disability using visual evoked potentials

Abstract

BackgroundThe purpose of this study is to validate the use of visual evoked potential (VEP) to objectively quantify visual acuity in normal and amblyopic patients, and determine if it is possible to predict visual acuity in disability assessment to register visual pathway lesions.MethodsA retrospective chart review was conducted of patients diagnosed with normal vision, unilateral amblyopia, optic neuritis, and visual disability who visited the university medical center for registration from March 2007 to October 2009. The study included 20 normal subjects (20 right eyes: 10 females, 10 males, ages 9–42 years), 18 unilateral amblyopic patients (18 amblyopic eyes, ages 19–36 years), 19 optic neuritis patients (19 eyes: ages 9–71 years), and 10 patients with visual disability having visual pathway lesions. Amplitude and latencies were analyzed and correlations with visual acuity (logMAR) were derived from 20 normal and 18 amblyopic subjects. Correlation of VEP amplitude and visual acuity (logMAR) of 19 optic neuritis patients confirmed relationships between visual acuity and amplitude. We calculated the objective visual acuity (logMAR) of 16 eyes from 10 patients to diagnose the presence or absence of visual disability using relations derived from 20 normal and 18 amblyopic eyes.ResultsLinear regression analyses between amplitude of pattern visual evoked potentials and visual acuity (logMAR) of 38 eyes from normal (right eyes) and amblyopic (amblyopic eyes) subjects were significant [y = −0.072x + 1.22, x: VEP amplitude, y: visual acuity (logMAR)]. There were no significant differences between visual acuity prediction values, which substituted amplitude values of 19 eyes with optic neuritis into function. We calculated the objective visual acuity of 16 eyes of 10 patients to diagnose the presence or absence of visual disability using relations of y = −0.072x + 1.22 (−0.072). This resulted in a prediction reference of visual acuity associated with malingering vs. real disability in a range >5.77 μV. The results could be useful, especially in cases of no obvious pale disc with trauma.ConclusionsVisual acuity quantification using absolute value of amplitude in pattern visual evoked potentials was useful in confirming subjective visual acuity for cutoff values >5.77 μV in disability evaluation to discriminate the malingering from real disability.

Pattern and Sweep Visual Evoked Potential in the Objective Determination of Visual Acuity

“…The VEP is a sensitive test used to evaluate the optic nerve functions and is valuable in diagnosing optic nerve diseases such as demyelinating disease, optic neuritis, and optic neuropathy. In addition, it can be used to measure visual function by transmitting the ganglion cell response, which is formed by the flash or pattern stimulus, to the occipital cortex [1][2][3][4][5][6].…”

“…The reproducibility of the pVEP in a given same case is relatively high. In addition, the waveform, amplitude, and latency variations are low, when performed with standardized methods in normal individuals [1][2][3][4][5][6][7].…”

“…In a study conducted in the office setting, the authors concluded that the pVEP test recorded in different sizes could be used safely in cases of functional loss of vision. Jeon et al (12) performed a pVEP test to identify the degree of visual disability and reported that the pVEP was useful for confirming VA [12].…”

“…Until now, a number of tests for the measurement of VA have been developed. In the ophthalmology practice, electrophysiological tests can be used to measure the VA in infants, in non-cooperative cases, and in cases where the refraction is unable to be assessed due to media opacity and in the functional visual loss [1][2][3][4][5][6][7][8][9]. In addition, electrophysiological tests are the main tools of objective measurement of the vision in medico-legal conditions for clinicians [10].…”

Pattern-reversal visual evoked potentials as a diagnostic tool for ocular malingering

“…The visual evoked potential (VEP) test has been used to evaluate functionality of the visual pathway, and the pattern-re versal (PR)-VEP has been used as an objective assessment of VA. Previous studies have used the PR-VEP to objectively assess the visual pathway by comparing the results achieved with normative amplitude and latency values (11) . The present study investigated the contributions of pattern-reversal transient VEPs to diagnose malingering in patients treated at a university hospital in Brazil.…”