Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/14051
Title: The detection of small relative simulated field defects using multifocal VEPs
Authors: Chan, HHL 
Chu, HW
Ng, YF
Tam, WK
Young, SM
Lam, CH
Cheung, AL
Keywords: Multifocal VEP (mfVEP)
Retinal eccentricity
Simulated field defect
Visual field
Issue Date: 2005
Publisher: Wiley-Blackwell
Source: Ophthalmic and physiological optics, 2005, v. 25, no. 3, p. 224-232 How to cite?
Journal: Ophthalmic and physiological optics 
Abstract: Introduction: The multifocal visual-evoked potential (mfVEP) has been widely used in the study of diseases of the visual system. However, the sensitivity of the mfVEP in the objective detection of relative field defects has not been determined. This study investigates variations in mfVEP responses while simulating relative field defects by using different luminous transmission masks [neutral density (ND) filters] on the stimulus pattern. Methods: Simulated relative field defects with four different luminous transmissions were obtained by using 0.2, 0.4, 0.6, and 0.8 ND filters, 5 degrees in size, at two different retinal eccentricities (10 and 16 degrees) on a standard mfVEP dartboard stimulus. Eleven normal subjects were recruited for mfVEP measurements. The response amplitudes and latencies of the N1 and P1 of the mfVEP, with and without small simulated relative field defects, were compared. Results: The mfVEP amplitudes of N1 and P1 decreased substantially when 0.6 and 0.8 ND filters were introduced. The effects were similar at both the 10- and 16-degree eccentricities but there was no change in latency with simulated field defects at either location. Conclusions: The mfVEP can detect a simulated relative field defect 5 degrees in size starting with 0.6 log unit reduction in luminance at both 10-degree and 16-degree eccentricities. This illustrates that the sensitivity of the mfVEP measurement is nearly comparable with that of the Humphrey Visual Field Analyser.
URI: http://hdl.handle.net/10397/14051
ISSN: 0275-5408
EISSN: 1475-1313
DOI: 10.1111/j.1475-1313.2005.00273.x
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