Visual evoked potentials (VEPs) can provide important diagnostic information regarding the functional integrity of the visual system. This document updates the ISCEV standard for clinical VEP testing and supersedes the 2009 standard. The main changes in this revision are the acknowledgment that pattern stimuli can be produced using a variety of technologies with an emphasis on the need for manufacturers to ensure that there is no luminance change during pattern reversal or pattern onset/offset. The document is also edited to bring the VEP standard into closer harmony with other ISCEV standards. The ISCEV standard VEP is based on a subset of stimulus and recording conditions that provide core clinical information and can be performed by most clinical electrophysiology laboratories throughout the world. These are: (1) Pattern-reversal VEPs elicited by checkerboard stimuli with large 1 degree (°) and small 0.25° checks. (2) Pattern onset/offset VEPs elicited by checkerboard stimuli with large 1° and small 0.25° checks. (3) Flash VEPs elicited by a flash (brief luminance increment) which subtends a visual field of at least 20°. The ISCEV standard VEP protocols are defined for a single recording channel with a midline occipital active electrode. These protocols are intended for assessment of the eye and/or optic nerves anterior to the optic chiasm. Extended, multi-channel protocols are required to evaluate postchiasmal lesions.

Visual evoked potentials (VEPs) can provide important diagnostic information regarding the functional integrity of the visual system. This document updates the ISCEV standard for clinical VEP testing and supersedes the 2004 standard. The major change in this revision is that test parameters have been made more precise to achieve better consistency of results within and between test centers. The ISCEV standard VEP protocols are defined for a single recording channel with a midline occipital active electrode. These protocols are intended for assessment of prechiasmal function; additional electrode sites are recommended for evaluation of chiasmal and postchiasmal function. ISCEV has selected a subset of stimulus and recording conditions that provide core clinical information and can be performed by most clinical electrophysiology laboratories throughout the world. These are: 1. Pattern-reversal VEPs elicited by checkerboard stimuli with large 1°(i.e., 60 min of arc; min) and small 0.25° (15 min In memory of Vaegan (1943Vaegan ( -2009: friend, dedicated ISCEV member, and member of this VEP standardization committee.

This document presents the current (2004) standard\ud for the visual evoked potential (VEP). The VEP\ud is an evoked electrophysiological potential that can\ud be extracted, using signal averaging, from the electroencephalographic\ud activity recorded at the scalp. The\ud VEP can provide important diagnostic information\ud regarding the functional integrity of the visual system.\ud The current standard presents basic responses\ud elicited by three commonly used stimulus conditions\ud using a single, midline recording channel with\ud an occipital, active electrode. Because chiasmal and\ud retrochiasmal diseases may be missed using a single\ud channel, three channels using the midline and two\ud lateral active electrodes are suggested when one goes\ud beyond the standard and tests patients for chiasmal\ud and retrochiasmal dysfunction.\ud Pattern reversal is the preferred technique for most\ud clinical purposes. The results of pattern reversal\ud stimuli are less variable in waveform and timing\ud than the results elicited by other stimuli. The pattern\ud onset/offset technique can be useful in the detection of\ud malingering and in patients with nystagmus, and the\ud flash VEP is particularly useful when optical factors\ud or poor cooperation make the use of pattern stimulation\ud inappropriate. The intent of this standard is that\ud at least one of these techniques should be included\ud in every clinical VEP recording session so that all\ud laboratories will have a common core of information\ud that can be shared or compared

PURPOSE. Multi-species biofilms associated with contact lens cases and lenses can predispose individuals to contact lensrelated inflammatory complications. Our study used cultureindependent methods to assess the relationship between the severity of contact lens-related disease and bacteria residing in biofilms of contact lens cases and lenses.METHODS. Contact lens cases and lenses from 28 patients referred to the West Virginia University Eye Institute and diagnosed as having mild keratitis, keratitis with focal infiltrates, or corneal ulcers were processed and evaluated for bacterial composition based on 16S ribosomal RNA gene sequencing. Cases and lenses from nine asymptomatic contact lens wearers were processed in a manner similar to controls. Relationships between disease severity, bacterial types, and bacterial diversity were evaluated statistically.RESULTS. Disease severity and presenting visual acuity correlated with an increase in the diversity of bacterial types isolated from contact lens cases. A significant difference also was observed in the number of bacterial types associated with the three clinical groups. Achromobacter, Stenotrophomonas, and Delftia were prevalent in all disease groups, and Achromobacter and Stenotrophomonas were present in one asymptomatic control. Scanning electron microscopy revealed that Achromobacter and Stenotrophomonas formed a biofilm on the surface of contact lenses.CONCLUSIONS. Culture-independent methods identified an association between disease severity and bacterial diversity in biofilms isolated from cases and lenses of patients with contact lens-related corneal disease. Achromobacter, Stenotrophomonas, and Delftia were predominant bacteria identified in our study, drawing attention to their emerging role in contact lensrelated disease. (Invest Ophthalmol Vis Sci. 2012;53:3896-3905)

Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7-12 years and 18-35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia.