Organizing Section: Visual Neuroscience Program Number: 4879 Poster Board Number: B0268 Presentation Time: 3:45 PM–5:30 PM Flash and Pattern ERG Findings in Schizophrenia and Their Relationships to Visual Function

Program Number: 4879 Poster Board Number: B0268 Presentation Time: 3:45 PM–5:30 PM Flash and Pattern ERG Findings in Schizophrenia and Their Relationships to Visual Function Steven Silverstein1, Docia Demmin1, Roché Matthew1, Quentin Davis2, Frank Taranto3, Aaina Menon1. 1Psychiatry, Rutgers University, Piscataway, NJ; 2LKC Technologies, Inc., Gaithersburg, MD; 3Diopsys, Inc., Pine Brook, NJ. Purpose: In this ongoing study we are using flash and pattern electroretinography (fERG and pERG) to clarify the contributions of retinal signaling abnormalities to previously reported changes in contrast sensitivity, visual acuity, and contour integration in people with schizophrenia. Methods: Data were collected on 24 patients and 25 age-matched healthy controls. fERG data were collected under both lightand dark-adapted conditions, using a range of flash intensities, backgrounds, and temporal frequencies. The primary fERG variables of interest were a-wave activity (reflecting photoreceptor response), b-wave activity (reflecting primarily bipolar cell activity) and the photopic negative response (PhNR) (reflecting ganglion cell activity). The primary pERG variables of interest were magnitude, magnitude D, and the magnitude D/magnitude ratio for low and high contrast stimuli. Results: On photopic fERG tests, schizophrenia patients demonstrated significantly weaker photoreceptor response when a flash was presented against an unlit background (p<.05), and during a steady-state flicker test (p<.005). On scotopic tests, the rate of response gain per unit of intensity increase was significantly weaker for patients than controls (group x condition interaction p=.001). In both lightand dark-adapted conditions, patients demonstrated weaker signaling of bipolar cells (ps < .005). The schizophrenia group was also characterized by a weaker PhNR (p<.05). Multiple tests’ aand bwave amplitudes were related to behavioral contrast sensitivity impairments in the schizophrenia group (ps < .05 or .001), but not to visual acuity or contour integration. The groups did not differ significantly on pERG variables. For patients only, significant relationships were observed between poorer contour integration and reduced pERG amplitudes and longer latencies (all ps either < .05 or .001). For controls only, higher pERG values were related to better near and far visual acuity (ps < .05 or .01). Conclusions: These data suggest that both reduced signaling of photoreceptor and bipolar cells, as well as attenuated response gain, are associated with schizophrenia. Both rod and cone responses appear to be affected, and these changes may be related to the contrast sensitivity reduction in this group. The issue of ganglion cell function in schizophrenia is less clear, but its relationships to contour integration warrant further study. Commercial Relationships: Steven Silverstein, None; Docia Demmin, None; Roché Matthew, None; Quentin Davis, LKC Technologies, Inc. (E); Frank Taranto, Diopsys, Inc. (E); Aaina Menon, None Program Number: 4880 Poster Board Number: B0269 Presentation Time: 3:45 PM–5:30 PM Pattern ERG as an objective measure of contrast senitivity function Rustum Karanjia3, 1, Jack J. Tian4, 3, Kirsten Anderson3, 4, Anne G. Irvine4, Kenneth L. Lu3, 4, Stuart G. Coupland1, 2, Alfredo A. Sadun4, 3. 1Ophthalmology, University of Ottawa, Ottawa, ON, Canada; 2Ottawa Hospital Research Institute, Ottawa, ON, Canada; 3Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA; 4Doheny Eye Institute, Los Angeles, CA. Purpose: Contrast sensitivity is difficult to objectively quantify. The pattern ERG (pERG) is an objective measure of retinal ganglion cell functionality. The purpose of this study is to determine if pERG can be used to objectively measure contrast sensitivity function at different spatial frequencies in healthy eyes. Methods: The right eye of 5 normal subjects with a mean age of 25 years were tested for this study. All subjects had no ocular disease, and had best corrected visual acuity of at least 20/20. The pERGs were recorded using an ISCEV compliant Espion E3 system (Diagnosys LLC, Lowel MA). Each subject had pERG testing at 7 different spatial frequencies (0.125, 0.25, 0.5, 0.75, 1, 2, and 5 cycles-per-degree (CPD)). At each CPD, subjects were tested across 7 black-and-white contrast intensities including 100%, 95%, 90%, 85%, 80%, 75% and 70% contrast. Each individual subjects’ data was then averaged to produce a single N95 amplitude value for each combination of contrast intensity and CPD. The contrast intensity at which the N95 amplitude of the response was half that at 100% contrast was determined for each data series. Results: There was a linear decrease in the N95 amplitude as contrast intensity decreased, across all CPD/spatial frequency trials for all subjects. The half maximal N95 amplitude occurred at increasing contrast intensities between 0.125 and 0.25 CPD and subsequently decreased until 5 CPD for all subjects. Conclusions: For healthy eyes, the half maximal N95 response produces an inverted “U”-shaped curve of increasing, followed by decreasing contrast sensitivity function at increasing spatial frequencies. This curve is similar to the inverted “U”-shaped curve of contrast sensitivity function produced using subjective methods of contrast detection. This can be a useful tool for objectively measuring contrast sensitivity function. Commercial Relationships: Rustum Karanjia; Jack J. Tian, None; Kirsten Anderson, None; Anne G. Irvine, None; Kenneth L. Lu, None; Stuart G. Coupland, None; Alfredo A. Sadun, None Support: RPB, IFOND, LHON.org