MULTIMODAL IMAGING OF IGG4-RELATED PAPILLITIS AND RETINAL DISEASE.

PURPOSE: To report a case of IgG4-related ophthalmic disease, which presented with papillitis and subretinal deposits. METHODS: Observational case report with multimodal imaging. RESULTS: A 52-year-old man with a history of persistent lymphadenopathy presented with decreased vision in his left eye. Funduscopic examination demonstrated cuticular drusen in both eyes and florid edema of the left optic nerve, along with scattered circumscribed grey-yellow subretinal deposits that were distinct from the cuticular drusen. Swept-source optical coherence tomography demonstrated a hyper-reflective subretinal material corresponding to the grey-yellow subretinal deposits on clinical examination along with diffuse outer retinal disruption. Fundus autofluorescence revealed scattered hypoautofluorescence corresponding to cuticular drusen and also larger patches of hypoautofluorescence corresponding to the grey-yellow subretinal deposits. Fluorescein angiography demonstrated hypofluorescence corresponding to the large subretinal deposits and leakage at the optic nerve. Lymph node biopsy demonstrated IgG4-positive plasma cells and elevated serum IgG4 levels leading to a diagnosis of IgG4-related ophthalmic disease. The patient was treated with oral prednisone with subsequent resolution of the optic nerve edema. CONCLUSION: We describe multimodal imaging of unique retinal and optic nerve findings associated with IgG4-related ophthalmic disease. Our report broadens the spectrum of ocular involvement associated with IgG4-related disease.

Vision Testing in the Evaluation of Concussion.

Traumatic brain injury results from an acute impact to the head causing brain dysfunction. Concussion is a form of mild traumatic brain injury. There are significant short- and long-term sequelae of concussion, and early diagnosis and management are key to recovery. Visual system symptoms and signs are common following concussion and have been shown to be a useful feature of concussion testing. Neuro-ophthalmic findings include abnormalities in the pupillary light reflex, accommodation, convergence, extraocular motility, steroacuity, as well as pursuit and saccades. Concussion generally occurs out of the medical setting, and access to a trained examiner or equipment to assist in diagnosis is limited. For this reason, much research is focused on developing a concussion test that is practical and reliable, and technology is likely to play an important role in this. Ultimately, no single test is a substitute for clinical judgment and multifaceted testing.

Sensitivity and specificity of short-duration transient visual evoked potentials (SD-tVEP) in discriminating normal from glaucomatous eyes.

PURPOSE: To evaluate the ability of the short-duration transient visual evoked potential (SD-tVEP) to discriminate between healthy eyes and eyes with early to advanced glaucomatous visual field loss. METHODS: We tested 30 eyes of 30 healthy controls and 45 eyes of 35 glaucoma patients. Normal eyes had 20/30 or better visual acuity and normal 24-2 Swedish interactive thresholding algorithm (SITA) Standard visual fields. Glaucoma was staged as mild (mean deviation, MD > -6.0 dB), moderate (MD between -6.0 and -12.0 dB), and severe (MD < -12.0 dB). There were 15 eyes in each group. SD-tVEPs were recorded using the Diopsys NOVA-LX System. Each eye was stimulated with a low (Lc) and a high (Hc) Michelson contrast checkerboard pattern. Each test resulted in an Lc and an Hc SD-tVEP response. Each response was evaluated for overall waveform quality, P100 latency, and P100 amplitude referenced to the N75. The sensitivity, specificity, negative predictor value (NPV), and positive predictor value (PPV) were calculated. RESULTS: Lc latency showed the highest accuracy for discrimination using receiver operating characteristic curves for high and low contrast parameters. The analysis for all subjects resulted in a 91.1% sensitivity, 93.3% specificity, 95.3% PPV, and an 87.5% NPV. Evaluating the mean Lc latency of the mild, moderate, and severe glaucoma patients against controls showed discrimination consistent with the glaucoma severity. CONCLUSIONS: Short-duration transient VEP objectively identified decreased visual function and discriminated between healthy and glaucomatous eyes, and also showed good differentiation between healthy eyes and those with early visual field loss. VEP may be useful for early diagnosis of glaucoma.

Receptive field structure varies with layer in the primary visual cortex.

Here we ask whether visual response pattern varies with position in the cortical microcircuit by comparing the structure of receptive fields recorded from the different layers of the cat's primary visual cortex. We used whole-cell recording in vivo to show the spatial distribution of visually evoked excitatory and inhibitory inputs and to stain individual neurons. We quantified the distribution of 'On' and 'Off' responses and the presence of spatially opponent excitation and inhibition within the receptive field. The thalamorecipient layers (4 and upper 6) were dominated by simple cells, as defined by two criteria: they had separated On and Off subregions, and they had push-pull responses (in a given subregion, stimuli of the opposite contrast evoked responses of the opposite sign). Other types of response profile correlated with laminar location as well. Thus, connections unique to each visual cortical layer are likely to serve distinct functions.

Functionally distinct inhibitory neurons at the first stage of visual cortical processing.

Here we explore inhibitory circuits at the thalamocortical stage of processing in layer 4 of the cat's visual cortex, focusing on the anatomy and physiology of the interneurons themselves. Our immediate aim was to explore the inhibitory mechanisms that contribute to orientation selectivity, perhaps the most dramatic response property to emerge across the thalamocortical synapse. The broader goal was to understand how inhibitory circuits operate. Using whole-cell recording in cats in vivo, we found that layer 4 contains two populations of inhibitory cells defined by receptive field class--simple and complex. The simple cells were selective for stimulus orientation, whereas the complex cells were not. Our observations help to explain how neurons become sensitive to stimulus orientation and maintain that selectivity as stimulus contrast changes. Overall, the work suggests that different sources of inhibition, either selective for specific features or broadly tuned, interact to provide appropriate representations of elements within the environment.

Synaptic physiology of the flow of information in the cat's visual cortex in vivo.

Each stage of the striate cortical circuit extracts novel information about the visual environment. We asked if this analytic process reflected laminar variations in synaptic physiology by making whole-cell recording with dye-filled electrodes from the cat's visual cortex and thalamus; the stimuli were flashed spots. Thalamic afferents terminate in layer 4, which contains two types of cell, simple and complex, distinguished by the spatial structure of the receptive field. Previously, we had found that the postsynaptic and spike responses of simple cells reliably followed the time course of flash-evoked thalamic activity. Here we report that complex cells in layer 4 (or cells intermediate between simple and complex) similarly reprised thalamic activity (response/trial, 99 +/- 1.9 %; response duration 159 +/- 57 ms; latency 25 +/- 4 ms; average +/- standard deviation; n = 7). Thus, all cells in layer 4 share a common synaptic physiology that allows secure integration of thalamic input. By contrast, at the second cortical stage (layer 2+3), where layer 4 directs its output, postsynaptic responses did not track simple patterns of antecedent activity. Typical responses to the static stimulus were intermittent and brief (response/trial, 31 +/- 40 %; response duration 72 +/- 60 ms, latency 39 +/- 7 ms; n = 11). Only richer stimuli like those including motion evoked reliable responses. All told, the second level of cortical processing differs markedly from the first. At that later stage, ascending information seems strongly gated by connections between cortical neurons. Inputs must be combined in newly specified patterns to influence intracortical stages of processing.