ORIGINAL RESEARCH ARTICLE Effect of different stimulus configurations on the visual evoked potential (VEP) Naveen K. Yadav • Diana P. Ludlam • Kenneth J. Ciuffreda Received: 15 August 2011 / Accepted: 2 March 2012 Ó Springer-Verlag 2012 Abstract The purpose of this study was to assess changes in the response profile of the pattern visual evoked potential (VEP) using three stimulus config- urations simulating visual-field scotomas: central circular and central blank fields increasing incremen- tally in diameter from 1° to 15°, hemi-field, and quadrant patterns. Five visually normal adult subjects (ages 22–68 years) were tested binocularly at 1 m for each stimulus configuration on 5 separate days. A checkerboard test pattern (64 9 64 black-and-white checks, 85 % contrast, 64 cd/m 2 luminance, 20 s of stimulus duration, 2-Hz temporal frequency) was used. The group mean VEP amplitude increased in a linear manner with increase in the central circular diameter (y = 0.805x ? 2.00; r = 0.986) and decrease in cen- tral blank field diameter (y =-0.769x ? 16.22; r = 0.987). There was no significant change in latency in nearly all cases. The group mean coefficient of variability results indicated that the VEP amplitude was repeatable for the different stimulus configura- tions. The finding of VEP response linearity for the circular stimulus fields, and repeatability for all stimulus configurations, suggests that the clinician may be able to use the VEP technique with the suggested test patterns as a rapid and simple tool for objective assessment for several types of visual-field defects for a range of abnormal visual conditions and special populations. Keywords Visual evoked potential (VEP) Á VEP amplitude Á VEP latency Á Visual fields Á Linearity Á Repeatability Introduction Visual-field testing is used to assess the integrity and functionality of the retinal and early afferent visual pathways. For example, it is used to detect and monitor the progression of visual-field loss in a range of ocular and/or neurological diseases, such as glaucoma, macular degeneration, retinitis pigmentosa (RP), acquired brain injury (ABI), Parkinson’s disease, and Alzheimer’s disease [1, 2]. However, in many cases, assessment of the visual field is considered to be unreliable with poor repeatability [3, 4]. In addition, it is a subjective, time-consuming method. Due to these potential problems, conventional visual-field testing has often been called into question. Furthermore, special populations with cognitive impairment (e.g., ABI) frequently have difficulty performing well with conventional subjective approaches to visual-field testing [5]. These individuals may not understand the task and/or remember the instructions. In addition, they may have limitations due to attentional deficits N. K. Yadav (&) Á D. P. Ludlam Á K. J. Ciuffreda Department of Biological and Vision Sciences, SUNY State College of Optometry, 33 West 42nd Street, New York, NY 10036, USA e-mail: nyadav@sunyopt.edu 123 Doc Ophthalmol DOI 10.1007/s10633-012-9319-0