Flash Visual Evoked Potentials Research Articles

The clinical efficacy of preoperative flash visual evoked potential (VEP) for mature cataracts without a response to pattern VEP.

This study aims to assess the effectiveness of the preoperative flash visual evoked potential (VEP) test in predicting postoperative visual acuity for monocular mature cataract cases when compared to the contralateral normal eye. The study included 60 patients, each with a monocular mature cataract diagnosis, who underwent preoperative flash VEP testing showing no pattern VEP response. Subsequently, phacoemulsification was performed. The relationship between the flash VEP test latency values (P1, N2, P2) and amplitude value (N2-P2), and the degree of visual acuity recovery 3 months post-cataract surgery, was evaluated using the LogMAR scale. Furthermore, a linear regression analysis was conducted to explore the connection between preoperative flash VEP components and postoperative visual acuity. The average age of the patients was 65.4 ± 13.6 years, with a range of 43 to 87 years. The study included 36 males and 24 females. A significant disparity in visual acuity was observed between the preoperative and 3-month postoperative stages (p < 0.001). The preoperative flash VEP test for mature cataracts revealed significant delays in P1, N2, and P2 latency, as well as a reduction in N2-P2 amplitude potential when compared to the contralateral normal eye (p < 0.001). Notably, delayed P2 latency and reduced N2-P2 amplitude potential were particularly indicative of poor visual acuity prognosis after cataract surgery in the multiple regression analysis (p < 0.05). The N2-P2 amplitude potential was the important value that exhibited statistically significant results, with an area under the curve (AUC) of 80% sensitivity and 88% specificity, using a cutoff value of 6.07 μV. In cases of monocular mature cataract, a reduction in N2-P2 amplitude potential compared to the contralateral normal eye emerged as the most reliable predictor of postoperative visual prognosis following cataract surgery.

SSFVEP as a potential electrophysiological examination for evaluating visual function of fundus diseases with vitreous hemorrhages: a clinical study

To investigate the sensitivity and potential application of steady-state flash visual evoked potentials (SSFVEP) in assessing the visual function of fundus diseases with vitreous hemorrhage. 18 patients diagnosed with monocular vitreous hemorrhages in the fundus were examined the flash visual evoked potentials (FVEP) and SSFVEP in both eyes. The difference in the P2-wave amplitude of FVEP and the average amplitude of SSFVEP waveform between the diseased eyes and those without vitreous hemorrhage were statistically compared. There was no significant difference in the waveform of FVEP between both eyes. The amplitude of P2-wave from FVEP of the diseased eye was slightly lower than that without vitreous hemorrhage. However, the difference was not statistically significant (P = 0.111). The waveform of SSFVEP in the eye without vitreous hemorrhage showed a towering shape, while that of the diseased eye was flat. The average amplitude of SSFVEP in the diseased eye was statistically lower than that without vitreous hemorrhage (P = 0.036). The difference ratio of SSFVEP amplitude between both eyes was significantly greater than that of FVEP amplitude (P = 0.028). In some fundus diseases with vitreous hemorrhage, SSFVEP had a higher sensitivity than FVEP, providing a novel potential application for visual function assessment.

BDNF and cAMP are neuroprotective in a porcine model of traumatic optic neuropathy.

Traumatic optic neuropathy (TON) is a devastating condition that can occur after blunt or penetrating trauma to the head, leading to visual impairment or blindness. Despite these debilitating effects, no clinically available therapeutic targets neuroprotection or promotes axon regeneration in this or any optic neuropathy. Limited data in large-animal models are a major obstacle to advancing treatments toward clinical therapeutics. To address this issue, we refined a surgical model of TON in Yucatan minipigs. First, we validated the model by demonstrating visual impairment by flash visual-evoked potential and retinal ganglion cell degeneration and death. Next, we developed and optimized a delivery method and nontoxic dosing of intravitreal brain-derived neurotrophic factor (BDNF) and cAMP. Finally, we showed that intravitreal injection of BDNF and cAMP rescued visual function and protected against retinal ganglion cell death and optic nerve axon degeneration. Together these data in a preclinical large-animal model advance our understanding of and ability to model TON and further identify and develop candidate clinical therapeutics.

The role of electrophysiology tests and multimodal imaging in evaluation of nystagmus

Purpose This work aimed to highlight the role of electrophysiology testing and multimodal imaging in evaluation of nystagmus. Patients and methods This is a retrospective multi-centered analytic study that recruited patients with nystagmus from the outpatient clinics referred to the electrophysiology units of the hospitals of the University of Minia, Ain Shams, Banha, and Cairo, Egypt. The study included 60 (120 eyes) patients. The performed investigations included full-field electroretinography (ffERG), pattern electroretinography, flash visual evoked potential (FVEP), pattern visual evoked potential, optical coherence tomography (OCT), OCT-angiography (OCT-A), and fundus autofluorescence (FAF), whenever possible. Results There were no or minimal detectable fundus changes in 78 (65%) eyes, of which 40 (33.3%) eyes showed severe loss of photopic responses on ffERG, with Bull’s eye pattern observed on FAF and loss of foveal photoreceptors in OCT, while 18 (12.5%) eyes showed reduced photopic and scotopic responses in ffERG with loss of foveal photoreceptors and thinned parafovea in OCT, 14 (11.7%) eyes showed average photopic and scotopic responses with different stages of foveal hypoplasia in OCT and OCT-A, and six (5%) eyes showed normal results in tests assessing the function and structure of the macula and optic nerve, including ERG, FVEP, and OCT. On the other hand, macular or optic nerve abnormalities were observed in 42 (35%) eyes, of which 20 (16.7%) eyes showed significant loss of photopic responses in ffERG and abnormal fovea in OCT and FAF tests, 10 (8.3%) eyes showed loss of photopic and scotopic responses in ffERG and abnormal results in the OCT and FAF, four (3.3%) eyes had normal results in ERG and FVEP, but showed fovea hypoplasia in OCT, and eight (6.7%) eyes had normal photopic and scotopic responses by ffERG, but with abnormal visual evoked potential responses and thinning of the nerve fiber layer in the OCT. Conclusion Electrophysiological tests and multimodal imaging are crucial to diagnosing the underlying causes of nystagmus, especially in patients with normal fundus.

Visually evoked potentials in Neuro‐Ophthalmology

The first major development in the visually evoked potentials (VEP) was the move from flash to pattern stimulation in the 1970's. The neurophysiological basis of the responses to flash and to pattern stimuli will be reviewed to explain the superiority of the pattern VEP. The following questions will be considered: Why were the early findings in multiple sclerosis so influential? In what situations does the pVEP continue to be useful clinically, with particular emphasis on the classification of optic neuritis? Should VEP and ERG always be carried out in combination? When is flash VEP useful? Is there a role for a chromatic VEP?

First results of long-term follow-up of children in Russia after gene therapy for hereditary retinal dystrophies associated with biallelic mutations in the RPE65 gene

Purpose: to evaluate the results of gene therapy by the recombinant adeno-associated viral vector voretigene neparvovec (VN) in children with follow-up periods of 1, 3, 6, and 12 months.Material and methods. The study included 6 children (12 eyes) aged 5 to 15 with a confirmed biallelic mutation in the RPE65 gene, treated with VN (Luxturna, USA). Treatment efficacy was assessed by surveying which included questions on spatial orientation under various types of illumination, Goldman perimetry, microperimetry, best corrected visual acuity (BCVA), electroretinogram (ERG), and visual evoked potentials (VEP). To assess the structure of the retina, the central retinal thickness (CRT) was evaluated by optical coherence tomography.Results. All children showed subjective changes in visual perception, including improved orientation in the dark and twilight, and improved contrast. In one case, the child with initially low visual acuity showed improved visual fixation. In 4 patients out of 6 (8 eyes), an expansion of the visual fields was noted, including 2 cases who displayed significant expansion thereof. In 2 patients (4 eyes), the visual fields were not narrowed and remained so throughout the entire observation period. Mean light sensitivity of the retina in 3 patients and fixation indices in 1 patient improved significantly as shown by microperimetry. BCVA remained stable throughout the study or changed insignificantly. Initially, ERG could not be detected in 8 eyes, but after an VN injection, 6 eyes demonstrated a partial recovery at different times — from 1 to 12 months. An increase in the amplitude of the P1 component to pattern VEP and P2 component to flash VEP was observed in all patients, which indicates an enhanced activity in the projection of the visual cortex after the restoration of the visual cycle. No significant changes were revealed in CRT (p = 0.9). Complications and adverse events were noted in 9 eyes (75 %): chorioretinal dystrophy at the injection site in 3 patients (5 eyes), multifocal nummular dystrophy in 2 patients (4 eyes), local episcleritis in 1 eye, transient increase in intraocular pressure in 2 patients (3 eyes).Conclusion. The results of a one-year post VN treatment follow-up of Russian patients with RPE65-associated inherited retinal disease demonstrate stabilization and improvement of visual functions, which is especially important for otherwise incurable patients with a progressive course of the disease.

Silicone oil insulation effects on flash electroretinogram and visual evoked potential in patients with retinal detachment

BackgroundSilicone oil is used as endotamponade following vitreoretinal surgery to maintain the retina reattached when indicated. This study investigates the hypothesis that silicone oil causes insulation effects on the retina by affecting its response to light. MethodsElectrophysiological responses to a flash stimulus were recorded using full-field electroretinography (ERG) and visual evoked potentials (VEP). Recordings were performed in 9 patients who underwent surgery for retinal detachment, before (1–2 days) and after (2–3 weeks) silicone oil removal (SOR) in both the study and the control eye. Flash ERG and VEP recordings were performed according to the ISCEV standard protocol. ResultsStatistically significant differences were found in the study eye in the amplitudes of the ERG responses and their corresponding ratios, i.e. the amplitude after SOR over the amplitude before SOR, in all conditions tested. No differences were observed in the control eye. The mean ratio of photopic ERG response was 3.4 ± 2.4 for the study and 1.0 ± 0.3 for the control eye (p<0.001). The mean ratio of ERG flicker response was 3.1 ± 2.4 and 1.0 ± 0.3, respectively (p = 0.003). Scotopic flash ERG ratio was 5.0 ± 4.4 for the study and 1.3 ± 0.6 for the control eye (p = 0.012). No differences were observed for the amplitude and latency of flash VEP response after SOR. ConclusionsSilicone oil causes a reduction in flash ERG responses; no effect was found on flash VEP responses. ERGs in eyes filled with silicone oil should not be considered representative of retinal functionality, in contrast to VEPs, which are not affected by silicone oil presence.

The clinical research on the effect of hydrogen-rich water on primary retinitis pigmentosa

ObjectiveTo investigate the feasibility and effectiveness of hydrogen in the treatment of retinitis pigmentosa (RP) patients through the drinking of hydrogen-rich water (HRW). MethodsRP patients clinically diagnosed in our hospital were selected and given HRW for drinking at 400–500 ml twice a day for four consecutive weeks. Changes in best corrected visual acuity (BCVA), intraocular pressure, the retinal thickness, and choroidal thickness, as well as the amplitude and peak time of visual electrophysiological examinations before and after HRW drinking were observed. Data were statistically analyzed. ResultsIn total, 24 eyes of 13 patients with RP (3 males and 10 females aged–27-65 years old, were enrolled in the study. The BCVA after HRW drinking was 0.34 ± 0.25, which was statistically improved compared with that before (P < 0.05). There were no significant differences in intraocular pressure, retinal lhickness, or choroidal thickness before and after HRW drinking (all P > 0.05). The amplitudes of the b-wave in Dark-adaptation 0.01 response, a and b waves in Dark-adaptation 3.0 response, the Dark-adaptation Ops total wave, a and b waves in Light-adaptation 3.0 response, and the Light-adaptation Flicker response of electroretinogram (ERG) were significantly higher than those before HRW drinking (all P < 0.05). The corresponding peak times iwere mproved to some extent compared to those before HRW consumption (all P < 0.05). Six patients with RP (11 eyes) had a BCVAm ore than 20/200. The amplitude and peak time of the P100 -ave from the 1°p attern visual evoked potentials (PVEP) were not significantly different from those before HRW drinking (P > 0.05), while the data from the 15′ PVEP were statistically different (P < 0.05). Seven patients with RP (13 eyes) had a BCVA less than. 20/200 No significant differences were found in the amplitude and peak time of the P2 wave from the 1.0 Hz flash visual evoked potentials (FVEP) and the amplitude from the 12 Hz FVEP compared with those before HRW drinking (all P > 0.05). ConclusionShort-term HRW drinking slightly improved visual function in patients with primary RP, whereas no significant improvement was found in the thickness of the retina and choroid.

Activation of p38 MAPK hinders the reactivation of visual cortical plasticity in adult amblyopic mice

ObjectiveTo investigate the impact of p38 mitogen-activated protein kinase (MAPK) signaling on reactivating visual cortical plasticity in adult amblyopic mice. Materials and methodsReverse suture (RS), environment enrichment (EE), and combined with left intracerebroventricular injection of p38 MAPK inhibitor (SB203580, SB) or p38 MAPK agonist (dehydrocorydaline hydrochloride, DHC) were utilized to treat adult amblyopic mice with monocular deprivation (MD). The visual water task, visual cliff test, and Flash visual-evoked potential were used to measure the visual function. Then, Golgi staining and transmission electron microscopy were used to assess the reactivation of structural plasticity in adult amblyopic mice. Western blot and immunohistochemistry detected the expression of ATF2, PSD-95, p38 MAPK, and phospho-p38 MAPK in the left visual cortex. ResultsNo statistically significant difference was observed in the visual function in each pre-intervention group. Compared to pre-intervention, the visual acuity of deprived eyes was improved significantly, the impairment of visual depth perception was alleviated, and the P wave amplitude and C/I ratio were increased in the EE + RS, the EE + RS + SB, and the EE + RS + DMSO groups, but no significant difference was detected in the EE + RS + DHC group. Compared to EE + RS + DHC group, the density of dendritic spines was significantly higher, the synaptic density of the left visual cortex increased significantly, the length of the active synaptic zone increased, and the thickness of post-synaptic density (PSD) thickened in the left visual cortex of EE + RS, EE + RS + SB, and EE + RS + DMSO groups. And that, the protein expression of p-p38 MAPK increased while that of PSD-95 and ATF2 decreased significantly in the left visual cortex of the EE + RS + DHC group mice. ConclusionRS and EE intervention improved the visual function and synaptic plasticity of the visual cortex in adult amblyopic mice. However, activating p38 MAPK hinders the recovery of visual function by upregulating the phosphorylation of p38 MAPK and decreasing the ATF2 protein expression.

P.141 The value of using flash visual evoked potentials monitoring during minimally invasive endoscopic meningioma resection: a retrospective chart review

Background: Endoscopic endonasal surgeries performed in areas involving the visual pathway are associated with postoperative visual dysfunction. We previously demonstrated that continued eye monitoring during surgery by flash visual evoked potential (FVEP) represents a good method to prevent/reduce visual deficit post-surgery. We wondered whether FVEP monitoring may be more beneficial in patients with meningioma, strongly associated with postoperative visual loss.The aim was to explore the visual capacity in patients subjected to meningioma resection at The Ottawa Hospital. Methods: A retrospective chart review of patients who underwent minimally invasive endoscopic skull base surgery and FVEP monitoring for meningioma resection (July 2018 to present) was conducted. Only patients with available pre- (up to 3 months) and post-surgery (1-9 months) visual evaluation were analyzed. Results: 40 eyes were included (20 patients). The median age was 61 years (range:43-84) and 90% of patients were female. The LogMAR visual acuity was not significantly modified post-surgery (from +0.25 to +0.21; p=0.7). Color vision (# errors reading Ishihara/16-plates) was not modified post-surgery (from 2.6 to 3.2; p=0.6). Visual field (Humphrey, 32-2) was not significantly modified post-surgery (from 78.1% to 81.9%; p=0.7). Conclusions: The prevention of visual pathway injury during surgery by FVEP monitoring prevents visual deficits after endoscopic meningioma resection.

Interleukin-17A modulates retinal inflammation by regulating microglial activation via the p38 MAPK pathway in experimental glaucoma neuropathy.

As a prototypical member of the IL-17 family, interleukin-17A (IL-17A) has received increasing attentions for its potent proinflammatory role as well as potential to be a key therapeutic target in human autoimmune inflammatory diseases; however, its roles in other pathological scenarios like neuroinflammations are not fully elucidated yet but appear essentially correlating and promising. Glaucoma is the leading cause of irreversible blindness with complicated pathogenesis still to be understood, where neuroinflammation was reported to be critically involved in its both initiation and progression. Whether IL-17A takes part in the pathogenesis of glaucoma through interfering neuroinflammation due to its potent proinflammatory effect is still unknown. In the present study, we investigated the role of IL-17A in the pathological process of glaucoma neuropathy as well as its relationship with the predominant immune inflammation mediator microglia in retina, trying to elucidate the underlying mechanisms from the view of inflammation modulation. In our study, RNA sequencing was performed for the retinas of chronic ocular hypertension (COH) and control mice. Western blot, RT-PCR, immunofluorescence, and ELISA were used to evaluate the microglial activation and proinflammatory cytokines release at conditioned levels of IL-17A, along with assessment of optic nerve integrity including retinal ganglion cells (RGCs) counting, axonal neurofilament quantification, and flash visual-evoked potential (F-VEP) examination. And the possibly involved signaling pathways were screened out to go through further validation in scenarios with conditioned IL-17A. Subsequently, IL-17A was found to be significantly upregulated in COH retina. Furthermore, suppression of IL-17A effectively diminished the loss of RGCs, improved axonal quality, and F-VEP performance in COH mice. Mechanistically, IL-17A promoted microglial activation and proinflammatory cytokines release along with enhanced phenotypic conversion of activated microglia to M2-type in early stage and to M1-type in late stage in glaucomatous retinas. Microglia elimination decreased the proinflammatory factors secretion, enhanced the RGCs survival and axonal quality mediated by IL-17A. Furthermore, IL-17A-induced the overactivation of microglia in glaucomatous condition was alleviated after blocking the p38 MAPK pathway. Taken together, IL-17A is involved in the regulation of retinal immune response and RGCs cell death in experimental glaucoma by essentially promoting retinal microglial activation via p38 MAPK signaling pathway. IL-17A dynamically regulates the phenotypic conversion of retinal microglia in experimental glaucoma partly depending on the duration of elevated intraocular pressure. Suppression of IL-17A contributes to alleviate glaucoma neuropathy and exhibits promising potential as an innovative target for therapeutic strategy in glaucoma.

879 Monitoring Flash Visual Evoked Potentials During Endoscopic Skull Base Surgery Reduces the Risk of Visual Pathway Injury

INTRODUCTION: Minimally invasive endoscopic endonasal skull base surgery offer safer and more effective access to the skull base to remove benign and malignant tumors. However, endoscopic skull base surgery around the visual pathway may increase the risk of injury of the visual pathway. Monitoring of flash visual evoked potentials (FVEPs) during surgery may detect a possible injury to the visual pathway, allowing the surgeon to take corrective measures during surgery to reverse or minimize it. METHODS: We identified patients with chiasmatic or pre-chiasmatic lesions who underwent minimally invasive endoscopic skull base surgery. Patients were subjected to eye exam (color vision, visual acuity, and visual field evaluation) within 3 months before surgery, and within 6-12 weeks and 6-9 months after surgery to explore short- and long-term surgical outcomes on eyesight. During surgery, FVEPs were recorded from electrodes placed in the scalp overlying the visual cortex after flashing red light stimulation (Cadwell LED stimulating goggles), as reported previously. We examined the relationship between FVEPs amplitude change and visual outcome on these patients. RESULTS: 102 patients have been enrolled in this retrospective study. The median age at admission was 57 years (range: 22-86 years) and 68.4% of the patients were female. Most of the patients had either pituitary adenoma (64.7%) or skull base meningioma (23.5%). Preliminary eye evaluations (pre- and post-surgery) showed that the patients did not develop short- or long-term eyesight impairments. CONCLUSIONS: Our study provides a new method for rapidly acquiring reproducible FVEP waves for which allows for timely reporting significant FVEP changes resulting in prompt signal action. Thus, monitoring FVEPs during endoscopic endonasal skull base surgery reduces the risk of visual pathway injury.

Function Evaluation of Diabetic Vitreous Hemorrhage After Vitrectomy

Purpose: The aim of this study is to evaluate electrophysiological changes before and after pars plana vitrectomy for diabetic vitreous hemorrhage Subject &amp; Method: This study included 30 eyes of 30 patients with diabetic vitreous hemorrhage undergoing pars plana vitrectomy. All subjects underwent complete ophthalmological examination, Ultrasonography, Visual evoked potential, Electroretinography before and after vitrectomy (at 1 week &amp;3 months) Results: There was a statistically significant improvement in the Uncorrected Visual Acuity (UCVA) and the Best Corrected Visual Acuity (BCVA) along the study period (p &lt;0.001). There was statistically significant improvement in the mean latency and mean amplitude of Flash VEP There was a statistically significant increase in the mean amplitude of all ERG parameters at 3 months postoperative. Conclusion: Electrophysiological test is an important tool in detection improvement of retinal function after vitrectomy

Prognosticators for Visual Outcome in Indirect Traumatic Optic Neuropathy: A Prospective Cohort Study.

Introduction Traumatic optic neuropathy (TON), with indirect TON as its more prevalent form, is a dreadful cause of severe visual dysfunctions. The condition is known to have a contentious treatment plan and poor visual sequelae; hence, the assessment of prognostic signs becomes valuable. Prospective studies evaluating important predictors of visual recovery after traumatic optic nerve injury can particularly be helpful in a longitudinal observation. The possible roles of clinical variables need to be assessed. Absent visual evoked potential (VEP) records as a crucial finding associated with TON has reportedly valuable prognostic significance. This also needs to be explored. Hence, the study sought to determine the role of prognosticators in the visual outcome of the patients, with a focus on evaluating the role of VEPs in the severity and prognosis of indirect TON. Methods A prospective observational study involving 40 patients with indirect TON was conducted. Ocular, neuro-ophthalmological, radiological, and neurophysiological variables, including flash VEP, were investigated at their initial visit and followed up until the end of six months. Final visual acuity was the primary outcome variable studied. Paired t-test was used to perform the comparison between the flash VEP variables for normal and affected eyes at the initial visit. Pearson correlation coefficient was computed for obtaining the association of initial visual acuity and flash VEP variables with the outcome variable. Relative risk was calculated and analysed for the prognosticators in univariate analysis. Statistical significance was defined as p < 0.05. Results Statistically significant variations in mean P100 latency, N75-P100, and P100-N145 amplitudes compared between normal and affected eyes in the patients at the initial visit were obtained (p < 0.0001; paired t-test). Pearson correlation coefficient for initial visual acuity and flash VEP variable as independent variables and final visual acuity as the dependent variable were statistically significant (p < 0.05). The relative risks for prognosticators with a statistically significant range of confidence intervals were poor initial visual acuity, greater relative afferent pupillary defect (RAPD) grades, deranged flash VEP variables (absent VEP, reduction in amplitude ratio (>50%), and increased interocular latency differences), loss of consciousness during injury, age greater than 40 years, and lack of improvement after 48 hours of steroid treatment. Conclusion The identified negative prognosticators may be helpful in deciding the kind of therapeutic approach and predicting the visual outcome in patients with indirect TON.

Investigation of the Protective Effect of Extracellular Vesicle miR-124 on Retinal Ganglion Cells Using a Photolabile Paper-Based Chip.

Photolabile paper-based chips were developed to isolate extracellular vesicles (EVs) from small-volume samples (less than 30 µL), such as vitreous humor. Putative neuroprotective effects of EVs' microRNAs were investigated by using the paper chip and a rodent model with nonarteritic anterior ischemic optic neuropathy (rNAION). rNAION was established using laser-induced photoactivation of rose bengal administered intravenously. On days 0, 0.25, 1, 3, and 7 after rNAION induction, CD63-positive EV microRNAs (CD63+-EV miRNAs) in vitreous humor samples were enriched using the paper chip and assessed using microarray and quantitative RT-PCR analyses. The viability and visual function of retinal ganglion cells (RGCs) were further assessed by measuring photopic flash visual evoked potentials (FVEPs). We identified 38 different variations of CD63+-EV miRNAs with more than twofold altered expressions. Among them, M1-related miRNA, mR-31a-5p, and M2-related miRNA, miR-125a-5p, miR-182, miR-181a-5p, and miR-124-3, were capable of coordinating anti-inflammatory reactions during rNAION because of their capacity to activate macrophages. In particular, miR-124, having the most dramatic alteration of gene expression, was synthesized and injected intravitreally. Compared to controls, rats that received miR-124 had shown increased RGC survivability and improved visual function. Our research team has developed a paper-based chip capable of capturing EVs that can be released after UV exposure. The quantity and quality of EV-miRNAs extracted are adequate for microarray and quantitative RT-PCR analyses. Animal studies suggest that miR-124 may play a neuroprotective role in the natural recovery of rNAION and holds the potential to be a novel treatment option.

The classification of flash visual evoked potential based on deep learning

BackgroundVisual electrophysiology is an objective visual function examination widely used in clinical work and medical identification that can objectively evaluate visual function and locate lesions according to waveform changes. However, in visual electrophysiological examinations, the flash visual evoked potential (FVEP) varies greatly among individuals, resulting in different waveforms in different normal subjects. Moreover, most of the FVEP wave labelling is performed automatically by a machine, and manually corrected by professional clinical technicians. These labels may have biases due to the individual variations in subjects, incomplete clinical examination data, different professional skills, personal habits and other factors. Through the retrospective study of big data, an artificial intelligence algorithm is used to maintain high generalization abilities in complex situations and improve the accuracy of prescreening.MethodsA novel multi-input neural network based on convolution and confidence branching (MCAC-Net) for retinitis pigmentosa RP recognition and out-of-distribution detection is proposed. The MCAC-Net with global and local feature extraction is designed for the FVEP signal that has different local and global information, and a confidence branch is added for out-of-distribution sample detection. For the proposed manual features,a new input layer is added.ResultsThe model is verified by a clinically collected FVEP dataset, and an accuracy of 90.7% is achieved in the classification task and 93.3% in the out-of-distribution detection task.ConclusionWe built a deep learning-based FVEP classification algorithm that promises to be an excellent tool for screening RP diseases by using FVEP signals.

Impact of keratoprosthesis implantation on retinal and visual pathway function assessed by electrophysiological testing.

To investigate the impact of Boston Type I Keratoprosthesis (BI-Kpro) implantation on retinal and visual pathway function, respectively, assessed by full-field electroretinography (ERG) and visually evoked potentials (VEPs). This is a prospective interventional longitudinal study, and patients with BI-Kpro implantation were assessed preoperatively and at 3 and 12months after surgery. ERG, flash, and pattern-reversal VEPs (15' and 60' checks) along with visual acuity (VA) were performed. A total of 13 patients (24 to 88years of age) were included. Mean baseline VA (logMAR) improved from 2.30 to 1.04 at 3months and to 1.00 at 12months. Flash VEPs were normal in 6 (46%) patients and in 10 (77%) patients at the 12-month follow-up. PVEP was non-detectable in all patients preoperatively for both check sizes. For 15' check size, 6 (46%) patients showed responses after 3 and 12months except for 1 patient with normal responses at 12months with the remaining non-detectable. For 60' checks, 11 (85%) patients had responses 3months after surgery with only 9 (70%) showing responses at 12months. Abnormal full-field ERGs were found in all patients preoperatively. Amplitude improvement was found in 10 (77%) patients from baseline to 3months and in 8 (62%) patients from the 3- to the 12-month follow-up. In this small cohort of patients with BI-Kpro implantation, a remarkable improvement on visual function quantitatively assessed by electrophysiological testing was found in the majority of cases. Visual electrophysiological testing can contribute to objectively assess functional outcomes in this population.

Neuroprotective Effects of Erinacine A on an Experimental Model of Traumatic Optic Neuropathy.

Erinacine A (EA), a natural neuroprotectant, is isolated from a Chinese herbal medicine, Hericium erinaceus. The aim of this study was to investigate the neuroprotective effects of EA in a rat model of traumatic optic neuropathy. The optic nerves (ONs) of adult male Wistar rats were crushed using a standardized method and divided into three experimental groups: phosphate-buffered saline (PBS control)-treated group, standard EA dose-treated group (2.64 mg/kg in 0.5 mL of PBS), and double EA dose-treated group (5.28 mg/kg in 0.5 mL of PBS). After ON crush, each group was fed orally every day for 14 days before being euthanized. The visual function, retinal ganglion cell (RGC) density, and RGC apoptosis were determined using flash visual-evoked potentials (fVEP) analysis, retrograde Fluoro-Gold labelling, and TdT-dUTP nick end-labelling (TUNEL) assay, respectively. Macrophage infiltration of ON was detected by immunostaining (immunohistochemistry) for ED1. The protein levels of phosphor-receptor-interacting serine/threonine-protein kinase1 (pRIP1), caspase 8 (Cas8), cleaved caspase 3 (cCas3), tumour necrosis factor (TNF)-α, tumour necrosis factor receptor1 (TNFR1), interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), nuclear factor erythroid 2-related factor 2 (Nrf2), haem oxygenase-1 (HO-1), and superoxide dismutase 1 (SOD1) were evaluated by Western blotting. When comparing the standard EA dose-treated group and the double EA dose-treated group with the PBS-treated group, fVEP analysis showed that the amplitudes of P1-N2 in the standard EA dose group and the double EA dose-treated group were 1.8 and 2.4-fold, respectively, higher than that in the PBS-treated group (p &lt; 0.05). The density of RGC in the standard EA dose-treated group and the double EA dose-treated group were 2.3 and 3.7-fold, respectively, higher than that in the PBS-treated group (p &lt; 0.05). The TUNEL assay showed that the standard EA dose-treated group and the double EA dose-treated group had significantly reduced numbers of apoptotic RGC by 10.0 and 15.6-fold, respectively, compared with the PBS-treated group (p &lt; 0.05). The numbers of macrophages on ON were reduced by 1.8 and 2.2-fold in the standard EA dose-treated group and the double EA dose-treated group, respectively (p &lt; 0.01). On the retinal samples, the levels of pRIP, Cas8, cCas3, TNF-α, TNFR1, IL-1β, and iNOS were decreased, whereas those of Nrf2, HO-1, and SOD1 were increased in both EA-treated groups compared to those in the PBS-treated group (p &lt; 0.05). EA treatment has neuroprotective effects on an experimental model of traumatic optic neuropathy by suppressing apoptosis, neuroinflammation, and oxidative stress to protect the RGCs from death as well as preserving the visual function.

Spontaneous regression of tumor in a girl with optic pathway glioma with diencephalic syndrome.

Spontaneous regression of tumor in a girl with optic pathway glioma with diencephalic syndrome.

Defects and asymmetries in the visual pathway of non-human primates with natural strabismus and amblyopia.

Strabismus and amblyopia are common ophthalmologic developmental diseases caused by abnormal visual experiences. However, the underlying pathogenesis and visual defects are still not fully understood. Most studies have used experimental interference to establish disease-associated animal models, while ignoring the natural pathophysiological mechanisms. This study was designed to investigate whether natural strabismus and amblyopia are associated with abnormal neurological defects. We screened one natural strabismic monkey ( Macaca fascicularis) and one natural amblyopic monkey from hundreds of monkeys, and retrospectively analyzed one human strabismus case. Neuroimaging, behavioral, neurophysiological, neurostructural, and genovariation features were systematically evaluated using magnetic resonance imaging (MRI), behavioral tasks, flash visual evoked potentials (FVEP), electroretinogram (ERG), optical coherence tomography (OCT), and whole-genome sequencing (WGS), respectively. Results showed that the strabismic patient and natural strabismic and amblyopic monkeys exhibited similar abnormal asymmetries in brain structure, i.e., ipsilateral impaired right hemisphere. Visual behavior, visual function, retinal structure, and fundus of the monkeys were impaired. Aberrant asymmetry in binocular visual function and structure between the strabismic and amblyopic monkeys was closely related, with greater impairment of the left visual pathway. Several similar known mutant genes for strabismus and amblyopia were also identified. In conclusion, natural strabismus and amblyopia are accompanied by abnormal asymmetries of the visual system, especially visual neurophysiological and neurostructural defects. Our results suggest that future therapeutic and mechanistic studies should consider defects and asymmetries throughout the entire visual system.