scholarly journals Clinical Applications of the Photopic Negative Response to Optic Nerve and Retinal Diseases

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Shigeki Machida
Keyword(s):  
Optic Nerve ◽  
Ganglion Cells ◽  
Objective Assessment ◽  
Visual Sensitivity ◽  
Negative Response ◽  
Photopic Negative Response ◽  
Retinal Diseases ◽  
Automated Perimetry ◽  
Retinal Ganglion ◽  
Standard Automated Perimetry

The photopic negative response (PhNR) in response to a brief flash is a negative-going wave following the b-wave of the cone electroretinogram (ERG) that is driven by retinal ganglion cells (RGCs). The function of RGCs is objectively evaluated by analysing the PhNR. We reviewed articles regarding clinical use of the PhNR. The PhNR was well correlated with the visual sensitivity obtained by standard automated perimetry and morphometric parameters of the inner retina and optic nerve head in optic nerve and retinal diseases. Moreover, combining the PhNR with focal or multifocal ERG techniques enables the objective assessment of local function of RGCs. The PhNR is therefore likely to become established as an objective functional test for optic nerve and retinal diseases involving RGC injury.

scholarly journals Prediction of glaucoma severity using parameters from the electroretinogram

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marc Sarossy ◽  
Jonathan Crowston ◽  
Dinesh Kumar ◽  
Anne Weymouth ◽  
Zhichao Wu
Keyword(s):  
Linear Models ◽  
Ganglion Cells ◽  
Objective Assessment ◽  
Multivariate Adaptive Regression Splines ◽  
Photopic Negative Response ◽  
Automated Perimetry ◽  
Standard Automated Perimetry ◽  
Functional Changes ◽  
Significant Difference ◽  
Better Than

AbstractGlaucoma is an optic neuropathy that results in the progressive loss of retinal ganglion cells (RGCs), which are known to exhibit functional changes prior to cell loss. The electroretinogram (ERG) is a method that enables an objective assessment of retinal function, and the photopic negative response (PhNR) has conventionally been used to provide a measure of RGC function. This study sought to examine if additional parameters from the ERG (amplitudes of the a-, b-, i-wave, as well the trough between the b- and i-wave), a multivariate adaptive regression splines (MARS; a non-linear) model and achromatic stimuli could better predict glaucoma severity in 103 eyes of 55 individuals with glaucoma. Glaucoma severity was determined using standard automated perimetry and optical coherence tomography imaging. ERGs targeting the PhNR were recorded with a chromatic (red-on-blue) and achromatic (white-on-white) stimulus with the same luminance. Linear and MARS models were fitted to predict glaucoma severity using the PhNR only or all ERG markers, derived from chromatic and achromatic stimuli. Use of all ERG markers predicted glaucoma severity significantly better than the PhNR alone (P ≤ 0.02), and the MARS performed better than linear models when using all markers (P = 0.01), but there was no significant difference between the achromatic and chromatic stimulus models. This study shows that there is more information present in the photopic ERG beyond the conventional PhNR measure in characterizing RGC function.

The Photopic Negative Response evaluation in patients with Leber's hereditary optic neuropathy

2021 ◽  
pp. 216-219
Author(s):  
M.S. Shmelkova ◽  
◽  
N.L. Sheremet ◽  
I.A. Ronzina ◽  
N.A. Andreeva ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Retinal Ganglion Cells ◽  
Optic Neuropathy ◽  
Ganglion Cells ◽  
Negative Response ◽  
Photopic Negative Response ◽  
Control Group ◽  
Retinal Ganglion ◽  
Leber's Hereditary Optic Neuropathy ◽  
Hereditary Optic Neuropathy

Purpose. To assess the retinal ganglion cells function in patients with Leber's hereditary optic neuropathy (LHON) by registering the photopic negative response (PhNR) while the photopic electroretinography is performed. Material and methods. 14 patients with different LHON mutations and 9 healthy individuals were examined. A standard ophtalmological examination was performed, including visual fields, spectral optical coherence tomography, photopic electroretinography and PhNR tests. Results. Significant differences in the PhNR latency (68.4±4.01/64.28±5.37, p<0,01) and the PhNR amplitude (21.5±9.34/32.72±12.73, p<0,003) were revealed in patients with LHON and the control group. The study revealed significant differences between the PhNR latency (р<0.01) and the PhNR amplitude (р<0.008) in patients with visual acuity (VA) ≤ 0.1 and the control group, and between the PhNR amplitude in patients with VA≥0.13 and the control group (р<0.05). There were found significant correlations between the PhNR parameters and visual acuity, mean sensitivity, RNFL and GCC thickness. A strong positive correlation was found between the PhNR amplitude and the GCC thickness in patients with VA≥0.3. Conclusion. The PhNR parameters reflect the retinal ganglion cells function in patients with LHON and correlate with RNFL and GCC structural changes. Key words: Leber hereditary optic neuropathy, mitochondrial optical neuropathies, retinal ganglion cell, photopic negative response, PhNR.

scholarly journals Can Variability of Pattern ERG Signal Help to Detect Retinal Ganglion Cells Dysfunction in Glaucomatous Eyes?

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Alberto Mavilio ◽  
Francesca Scrimieri ◽  
Donato Errico
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Second Harmonic ◽  
Pattern Electroretinogram ◽  
Mean Deviation ◽  
Automated Perimetry ◽  
Pattern Erg ◽  
Retinal Ganglion ◽  
Standard Automated Perimetry ◽  
Fiber Layer

Objective. To evaluate variability of steady-state pattern electroretinogram (SS-PERG) signal in normal, suspected, and glaucomatous eyes.Methods. Twenty-one subjects with suspected glaucoma due to disc abnormalities (GS), 37 patients with early glaucoma (EG), and 24 normal control (NC) were tested with spectral-domain optical coherence tomography (SD-OCT), standard automated perimetry (SAP), and SS-PERG. Mean deviation (MD), pattern standard deviation (PSD), retinal nerve fiber layer (RNFL), and ganglionar complex cells (GCC) were evaluated. The SS-PERG was recorded five consecutive times and the amplitude and phase of second harmonic were measured. PERG amplitude and coefficient of variation of phase (CVphase) were recorded, and correlation with structural and functional parameters of disease, by means of one-way ANOVA and Pearson’s correlation, was analysed.Results. PERG amplitude was reduced, as expression of retinal ganglion cells (RGCs) dysfunction, in EG patients and GS subjects compared to NC patients (P<0.0001). CVphase was significantly increased in EG patients and GS subjects, compared to healthy (P<0.0001), and it was also correlated with PSD (P=0.0009), GCC (P=0.028), and RNFL (P=0.0078) only in EG patients.Conclusions. Increased intrasession variability of phase in suspected glaucomatous eyes may be a sign of RGCs dysfunction.

scholarly journals Exploratory Study of the Association between the Severity of Idiopathic Intracranial Hypertension and Electroretinogram Photopic Negative Response Amplitude Obtained Using a Handheld Device

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 437
Author(s):  
Antony Raharja ◽  
Shaun M. Leo ◽  
Isabelle Chow ◽  
Mathura Indusegaran ◽  
Christopher J. Hammond ◽  
...  
Keyword(s):  
Intracranial Hypertension ◽  
Disease Severity ◽  
Idiopathic Intracranial Hypertension ◽  
Retinal Nerve Fibre Layer ◽  
Negative Response ◽  
Photopic Negative Response ◽  
Mean Deviation ◽  
Automated Perimetry ◽  
Standard Automated Perimetry ◽  
Handheld Device

The photopic negative response (PhNR) is a negative component of the photopic flash electroretinogram that follows the b-wave and is thought to arise from the retinal ganglion cells. Reduction in its amplitude in idiopathic intracranial hypertension (IIH) has been previously documented using formal electroretinography. This study explored the use of a handheld device (RETeval, LKC technologies, USA) in 72 IIH patients of varying stages and severity (and seven controls) and investigated associations between PhNR parameters and disease severity. PhNR amplitudes at 72ms (P72) and p-ratio (ratio to b-wave peak value) differed significantly across groups, with a trend towards smaller amplitudes in those with severe IIH, defined as papilloedema with Modified Frisén Scale (MFS) ≥ 3, retinal nerve fibre layer (RNFL) ≥ 150μm or atrophic papilloedema (p = 0.0048 and p = 0.018 for P72 and p-ratio, respectively). PhNR parameters did not correlate with MFS, RNFL thickness, standard automated perimetry mean deviation or macular ganglion cell layer volume. This study suggests that PhNR measurement using a handheld device is feasible and could potentially augment the assessment of disease severity in IIH. The clinical utility of PhNR monitoring in IIH patients requires further investigation.

scholarly journals Clinical electrophysiology of the optic nerve and retinal ganglion cells

Eye ◽  
2021 ◽  
Author(s):  
Oliver R. Marmoy ◽  
Suresh Viswanathan
Keyword(s):  
Optic Nerve ◽  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Retinal Ganglion Cell ◽  
Cell Function ◽  
Ganglion Cells ◽  
Pattern Electroretinogram ◽  
Photopic Negative Response ◽  
Clinical Electrophysiology ◽  
Retinal Ganglion

AbstractClinical electrophysiological assessment of optic nerve and retinal ganglion cell function can be performed using the Pattern Electroretinogram (PERG), Visual Evoked Potential (VEP) and the Photopic Negative Response (PhNR) amongst other more specialised techniques. In this review, we describe these electrophysiological techniques and their application in diseases affecting the optic nerve and retinal ganglion cells with the exception of glaucoma. The disease groups discussed include hereditary, compressive, toxic/nutritional, traumatic, vascular, inflammatory and intracranial causes for optic nerve or retinal ganglion cell dysfunction. The benefits of objective, electrophysiological measurement of the retinal ganglion cells and optic nerve are discussed, as are their applications in clinical diagnosis of disease, determining prognosis, monitoring progression and response to novel therapies.

Melatonin As a Modulator of Degenerative and Regenerative Signaling Pathways in Injured Retinal Ganglion Cells

2019 ◽  
Vol 25 (28) ◽  
pp. 3057-3073 ◽  
Author(s):  
Kobra B. Juybari ◽  
Azam Hosseinzadeh ◽  
Habib Ghaznavi ◽  
Mahboobeh Kamali ◽  
Ahad Sedaghat ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Mitochondrial Dysfunction ◽  
Signaling Pathways ◽  
Retinal Ganglion Cells ◽  
Molecular Mechanisms ◽  
Nitrosative Stress ◽  
Ganglion Cells ◽  
Axon Growth ◽  
Nerve Fibers ◽  
Retinal Ganglion

Optic neuropathies refer to the dysfunction or degeneration of optic nerve fibers caused by any reasons including ischemia, inflammation, trauma, tumor, mitochondrial dysfunction, toxins, nutritional deficiency, inheritance, etc. Post-mitotic CNS neurons, including retinal ganglion cells (RGCs) intrinsically have a limited capacity for axon growth after either trauma or disease, leading to irreversible vision loss. In recent years, an increasing number of laboratory evidence has evaluated optic nerve injuries, focusing on molecular signaling pathways involved in RGC death. Trophic factor deprivation (TFD), inflammation, oxidative stress, mitochondrial dysfunction, glutamate-induced excitotoxicity, ischemia, hypoxia, etc. have been recognized as important molecular mechanisms leading to RGC apoptosis. Understanding these obstacles provides a better view to find out new strategies against retinal cell damage. Melatonin, as a wide-spectrum antioxidant and powerful freeradical scavenger, has the ability to protect RGCs or other cells against a variety of deleterious conditions such as oxidative/nitrosative stress, hypoxia/ischemia, inflammatory processes, and apoptosis. In this review, we primarily highlight the molecular regenerative and degenerative mechanisms involved in RGC survival/death and then summarize the possible protective effects of melatonin in the process of RGC death in some ocular diseases including optic neuropathies. Based on the information provided in this review, melatonin may act as a promising agent to reduce RGC death in various retinal pathologic conditions.

scholarly journals Photoreceptive retinal ganglion cells control the information rate of the optic nerve

2018 ◽  
Vol 115 (50) ◽  
pp. E11817-E11826 ◽  
Author(s):  
Nina Milosavljevic ◽  
Riccardo Storchi ◽  
Cyril G. Eleftheriou ◽  
Andrea Colins ◽  
Rasmus S. Petersen ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Retinal Ganglion Cells ◽  
Information Flow ◽  
Information Transfer ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Ambient Light ◽  
Visual Responses ◽  
Light Irradiance ◽  
The Brain

Information transfer in the brain relies upon energetically expensive spiking activity of neurons. Rates of information flow should therefore be carefully optimized, but mechanisms to control this parameter are poorly understood. We address this deficit in the visual system, where ambient light (irradiance) is predictive of the amount of information reaching the eye and ask whether a neural measure of irradiance can therefore be used to proactively control information flow along the optic nerve. We first show that firing rates for the retina’s output neurons [retinal ganglion cells (RGCs)] scale with irradiance and are positively correlated with rates of information and the gain of visual responses. Irradiance modulates firing in the absence of any other visual signal confirming that this is a genuine response to changing ambient light. Irradiance-driven changes in firing are observed across the population of RGCs (including in both ON and OFF units) but are disrupted in mice lacking melanopsin [the photopigment of irradiance-coding intrinsically photosensitive RGCs (ipRGCs)] and can be induced under steady light exposure by chemogenetic activation of ipRGCs. Artificially elevating firing by chemogenetic excitation of ipRGCs is sufficient to increase information flow by increasing the gain of visual responses, indicating that enhanced firing is a cause of increased information transfer at higher irradiance. Our results establish a retinal circuitry driving changes in RGC firing as an active response to alterations in ambient light to adjust the amount of visual information transmitted to the brain.

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