Pattern Visual Evoked Potentials Research Articles

Effects of environmental enrichment on GLUT expression in the visual cortex of amblyopic rats

ObjectiveTo investigate the potential changes of glucose metabolism and glucose transporter protein (GLUT) in the visual cortex of formally deprived amblyopic rats, as well as the effects of enriched environments on the levels of nerve conduction and glucose metabolism in the visual cortex of amblyopic rats. Methods36 rats were randomly divided into three groups: CON + SE (n = 12), MD + SE (n = 12) and MD + EE (n = 12). The right eyelids of both MD + SE and MD + EE groups were sutured. After successful modelling, the MD + EE group was maintained in an enriched environment, and the other two groups were kept in the same environment. Pattern visual evoked potentials (PVEP) was used to confirm models' effect, glucose metabolism was analyzed by Micro-PET/CT (18F-FDG), and the protein as well as mRNA expression levels of GLUT were detected by Western Blot and quantitative RT-PCR (quantitative Reverse Transcription-Polymerase Chain Reaction) analyses, site of GLUT expression by immunofluorescence (IF). ResultsAfter suture modelling, both the MD + EE and MD + SE groups objective visual nerve conduction function decreased, the glucose metabolism in the visual cortex was markedly lower. After the enriched environment intervention, it recovered in the MD + EE group. The expression levels of GLUT1 and GLUT3 were increased in the MD + EE group in comparison with the MD + SE group. GLUT1 was primarily expressed on astrocytes and endothelial cells, but GLUT3 was mainly expressed on neurons. ConclusionEnrichment of the environment exhibited a therapeutic effect on amblyopia, which could be related to the enhancement of glucose metabolism and GLUT expression in the visual cortex.

Bone Marrow-derived Mesenchymal Stem Cell Therapy in Retinitis Pigmentosa.

To determine the effectiveness of bone marrow-derived mesenchymal stem cell therapy on visual acuity and visual field in patients with retinitis pigmentosa. Stem cell treatment in retinitis pigmentosa provides improvement in visual acuity and visual field. Forty-seven eyes of 27 patients diagnosed with retinitis pigmentosa were included in our study. Allogeneic bone marrow-derived mesenchymal stem cells were administered by deep subtenon injection. Complete routine ophthalmological examinations, optical coherence tomography (Zeiss, Cirrus HD-OCT) measurements, and visual field (Humphrey perimetry, 30-2) tests were performed on all patients before the treatment and on the 1st, 3rd, and 6th month after treatment. The best corrected visual acuities of the patients were determined by the Snellen chart and converted to logMAR. Visual evoked potential (VEP) and electroretinogram (ERG) examinations of the patients before the treatment and on the 6th month after the treatment were performed (Metrovision) data were compared. Visual acuities were 0.74 ± 0.49 logMAR before treatment and 0.61 ± 0.46 logMAR after treatment. Visual acuity had a statistically significant increase (p < 0.001). The visual field deviation was found to be -27.16 ± 5.77 dB before treatment and -26.59 ± 5.96 dB after treatment (p = 0.005). The ganglion cell layer was 46.26 ± 12.87 μm before treatment and 52.47 ± 12.26 μm after treatment (p = 0.003). There was a significant improvement in Pattern VEP 120º P100 amplitude compared to that before the treatment (4.43 ± 2.42 μV) and that after the treatment (5.09 ± 2.86 μV) (p = 0.013). ERG latency measurements were 18.33 ± 15.39 μV before treatment and 20.87 ± 18.64 μV after treatment for scotopic 0.01 (p = 0.02). ERG latency measurements for scotopic 3.0 were 20.75 ± 26.31 μV before treatment and 23.10 ± 28.60 μV after treatment (p = 0.014). Retinitis pigmentosa is a progressive, inherited disease that can result in severe vision loss. In retinitis pigmentosa, the application of bone marrow-derived mesenchymal stem cells by deep subtenon injection has positive effects on visual function. No systemic or ophthalmic side effects were detected in the patients during the 6-month follow-up period.

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.

Brain mechanism of acupuncture for children with anisometropic amblyopia: a resting functional magnetic resonance imaging study based on voxel-mirrored homotopic connectivity.

To explore the brain mechanism of acupuncture for children with anisometropic amblyopia using the voxel-mirror homotopic connectivity (VMHC) analysis method of resting functional magnetic resonance imaging (rs-fMRI) technology based on clinical effectiveness. Eighty children with anisometropic monocular amblyopia were randomly divided into two groups: control (40 cases, 1 case of shedding) and acupuncture (40 cases, 1 case of shedding) groups. The control group was treated with glasses, red flash, grating, and visual stimulations, with each procedure conducted for 5min per time. Based on routine treatment, the acupuncture group underwent acupuncture of "regulating qi and unblocking meridians to bright eyes", Jingming (BL1), Cuanzhu (BL2), Guangming (GB37), Fengchi (GB20) acupoints were taken on both sides, with the needle kept for 30min each time. Both groups were treated once every other day, three times per week, for a total of 4wk. After the treatment, the overall curative effect of the two groups and the latency and amplitude changes of P100 wave of pattern visual-evoked potential were counted. At the same time, nine children with left eye amblyopia were randomly selected from the two groups and were scanned with rs-fMRI before and after treatment. The differences in the brain regions between the two groups were compared and analyzed with VMHC. Chi-square test showed a notable difference in the total efficiency rate between the acupuncture (94.87%) and control groups (79.49%). Regarding the P100 wave latency and amplitude, the acupuncture group had significantly shorter latency and higher amplitude of P100 wave than the control group. Moreover, the VMHC values of the bilateral temporal lobe, superior temporal gyrus, and middle temporal gyrus were notably increased in the acupuncture group after treatment. Acupuncture combined with conventional treatment can significantly improve the corrected visual acuity and optic nerve conduction in children with anisometropic amblyopia. Compared with the conventional treatment, the regulation of acupuncture on the functional activities of the relevant brain areas in the anterior cerebellum may be an effective acupuncture mechanism for anisometropic amblyopia.

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.

Poster Session II: Alternating orientation of the chromatic pattern VEP improves signal even in the absence of contrast adaptation.

The visual evoked potential (VEP) to chromatic pattern reversal is greatly reduced compared to VEPs to pattern onsets. Chromatic pattern onsets produce large and stereotypical waveforms that reliably differ from standard achromatic pattern reversal VEP waveforms used in clinical applications. Rapid contrast adaptation for sustained chromatic but not transient achromatic mechanisms has been suggested as one explanation for these observations. Here we first examined changes in the magnitude of response during recordings to reversing and onset grating patterns that preferentially modulate the L-M, S, and achromatic pathways. Given the evidence for both chromatic and achromatic orientation-selective mechanisms, we then hypothesized that contrast adaptation may be reduced by changing the orientation of the pattern for each reversal or onset. VEPs were recorded for 60 s with 2 onsets/reversals per second using both fixed and alternating (horizontal/vertical) orientations. FFT amplitudes for 6-second windows did not reveal evidence of adaptation for chromatic or achromatic onsets or reversal patterns over the 60-second recording period. Despite this, alternating pattern orientation increased the signal for all chromatic but not achromatic conditions. Although alternating the orientation for reversals increased the signal, the onset responses were still larger, even for non-alternating orientations. Mechanisms other than contrast adaptation must be invoked to explain the results.

Evaluation of Fundus Function in Mature Cataract Patients by Visual Electrophysiology

Purpose. To explore the value of visual electrophysiology in evaluating the fundus function of mature cataract patients. Methods. 124 mature cataract patients (153 eyes) were examined before cataract surgery; the examinations included best corrected visual acuity (BCVA), pattern visual evoked potential (PVEP), full-field electroretinogram (ffERG), and multifocal electroretinogram (mfERG). According to the postoperative fundus conditions, the subjects were divided into two groups: the no fundus disease group and the fundus disease group. Approximately one month after the operation, BCVA was measured, and visual electrophysiology was performed on subjects who had a stable fundus condition and had not received treatment for fundus disease. Results. One month after cataract surgery, BCVA ≤ 0.3 logMAR was found in 60 eyes (96.8%) without fundus disease and 59 eyes (64.8%) with fundus disease. Compared with the group without fundus disease, the preoperative electrophysiological examination of the group with fundus disease showed that the amplitude of ffERG waves and the amplitude density of the P1 wave in the 2nd to 5th rings of mfERG were decreased (all P  &lt; 0.05). ffERG and mfERG can be used for differential diagnosis of fundus disease (all P  &lt; 0.05), while PVEP has no significant diagnostic value for fundus disease (all P  &gt; 0.05). In the group without fundus disease, the amplitude of the PVEP 15′ P100 wave and the amplitude of dark-adapted (DA) 0.01 b-wave, DA 3.0 a-wave, and DA 10.0 a-wave were negatively correlated with postoperative logMAR BCVA (all P  &lt; 0.05). In the group with fundus disease, the amplitude of PVEP and ffERG and the amplitude density of mfERG were negatively correlated with postoperative logMAR BCVA (all P  &lt; 0.05). In the eyes of cortical cataracts, some parameters of PVEP, ffERG, and mfERG were significantly different before and after surgery. In the eyes of nuclear cataracts, some parameters of ffERG and mfERG were significantly different before and after surgery. In the eyes of posterior subcapsular cataracts, some parameters of PVEP and ffERG were significantly different before and after surgery. Conclusions. ffERG and mfERG can be used to detect fundus disease in mature cataract patients. The preoperative visual electrophysiological examination has high clinical value in predicting postoperative vision of mature cataract patients with fundus disease. Different types of cataracts have different effects on electrophysiological examination results. When interpreting the electrophysiological report, it is necessary to consider the existence of cataracts. This trial is registered with 2019-K068.

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.

Pattern visual evoked potential and foveal sensitivity in amblyopia.

Amblyopic eyes show impaired visual functions such as poor visual acuity and reduced foveal sensitivity. The purpose of this study was to determine the association between foveal threshold and visual evoked potentials (VEP) in strabismic and anisometropic amblyopia. Forty-five subjects (age range: 7-28years, 43.3% female) including 15 strabismic and 15 anisometropic amblyopes, and 15 age-similar control subjectsparticipated in this study. Each subject had pattern visual evoked potentialsand foveal threshold recorded in each eye using RetiScan (Roland Consult, Germany) and Humphrey Visual Field Analyzer II (HFA II; Carl Zeiss Meditec Inc., Dublin, CA), respectively. These outcomes were comparedamong the amblyopic eyes, their fellow eyes, and the control eyes. Compared to the amblyopic eyes (Mean ± SD: 33.4 ± 3.48dB), the foveal threshold was higher in fellow eyes (37.0 ± 2.04dB, p = 0.0002) and incontrol eyes (38.7 ± 0.96dB, p < 0.0001). Strabismic amblyopes had a lower foveal threshold than anisometropic amblyopes (31.8 ± 3.86 vs. 35.0 ± 2.17dB, p = 0.005). Relative to the P100 peak time in fellow eyes (1°checks:116.1 ± 9.00ms; 0.25°checks:118.8 ± 5.67ms), amblyopic eyes had delayed P100 peak times for both 1° (122.7 ± 11.4ms, p < 0.0001) and 0.25° (130.4 ± 11.2ms, p < 0.0001) check sizes. There were also significant differences in P100 peak time between amblyopic and control eyes (1°:122.7 ± 11.4 vs.112.4 ± 5.01ms, p = 0.15; 0.25°:130.4 ± 11.2 vs.113.9 ± 5.71ms, p < 0.0001) and between fellow and control eyes (0.25°:118.8 ± 5.67 vs.113.9 ± 5.71ms, p = 0.009). Amblyopic eyes exhibited lower N75-P100 amplitudes than fellow eyes (1°:12.6 ± 7.96 vs.15.9 ± 8.82µV, p = 0.01; 0.25°:10.6 ± 6.11 vs. 15.8 ± 10.6µV, p = 0.001) and control eyes (0.25°: p = 0.0008). Foveal threshold correlated negatively with P100 peak time (1°: r = -0.45, p = 0.002 and 0.25°: r = -0.58, p < 0.0001) and positively with N75-P100 amplitude responses (1°: r = 0.42, p = 0.004 and 0.25°: r = 0.52, p = 0.002). Amblyopic eyes showed reduced pattern VEP amplitudes and delayed peak times with significant associations with the foveal sensitivity. However, the VEP measures overlapped extensively between amblyopic and control eyes with no apparent criterion value for optimal discrimination, suggesting that foveal sensitivity might be a better discriminator of amblyopia than pattern VEP.

Expression of early growth responsive gene-1 in the lateral geniculate body of kittens with amblyopia caused by monocular form deprivation.

The expression of early growth responsive gene-1 (Egr-1) in the lateral geniculate body in the normal kittens and those affected with amblyopia caused by monocular visual deprivation was compared to explore the potential significance of Egr-1 in the pathogenesis of amblyopia. A total of 30 healthy kittens were equally and randomly divided into the control (n = 15) and the deprivation group (n = 15). The kittens were raised in natural light and the right eyes of the deprived kittens were covered with a black opaque covering. Pattern visual evoked potential (PVEP) was measured before and 1, 3, and 5 weeks after covering. Five kittens from each group were randomly selected and euthanized with 2% sodium pentobarbital (100 mg/kg) during the 1st, 3rd and 5th week after covering. The expression of Egr-1 in the lateral geniculate body in the two groups was compared by performing immunohistochemistry and in situ hybridization. After three weeks of covering, PVEP detection indicated that the P100 wave latency in the deprivation group was significantly higher than that in the control group (P < 0.05), whereas the amplitude decreased markedly (P < 0.05). The number of the positive cells (P < 0.05) and mean optical density (P < 0.05) of Egr-1 protein expression in the lateral geniculate body of the deprivation group were found to be substantially lower in comparison to the normal group, as well as the number (P < 0.05) and mean optical density of Egr-1 mRNA-positive cells (P < 0.05). However, with increase of age, positive expression of Egr-1 in the control group showed an upward trend (P < 0.05), but this trend was not noted in the deprivation group (P > 0.05). Monocular form deprivation can lead to substantially decreased expressions of Egr-1 protein and mRNA in the lateral geniculate body, which in turn can affect the normal expression of neuronal functions in the lateral geniculate body, thereby promoting the occurrence and development of amblyopia.

Diagnostic Capability of Isolated-Check Visual Evoked Potential for Early to Moderate Primary Open-Angle Glaucoma.

This study aimed to evaluate the diagnostic capability of isolated-check visual evoked potential (icVEP) for primary open-angle glaucoma (POAG) via comparison with visual field (VF) tests and pattern visual evoked potential (PVEP). This cross-sectional study enrolled 68 subjects, including 33 POAG patients and 35 controls. All subjects underwent a complete ophthalmic examination, including icVEP, PVEP, and VF tests. The diagnostic performance, the area under the receiver operating characteristic curve (AUC), the integrated discrimination index (IDI), and the net reclassification index (NRI) were calculated. The clinical benefits of the three tests were compared via decision curve analysis (DCA) of the signal-to-noise ratio (SNR) from icVEP, the P100 latency and amplitude of 1° and 0.25° checks from the PVEP, pattern standard deviation (PSD), and mean deviation (MD) from the VF test. The SNR, MD and PSD, PVEP P100 latency of 0.25° checks, and P100 amplitude (both 1° and 0.25° checks) showed significant differences between the POAG and control groups (* p < 0.05), except for the P100 latency of 1° checks. Regarding diagnostic ability, the three tests, AUC, IDI, and NRI, showed no significant difference (p > 0.05). The DCA showed that the clinical benefits of icVEP (SNR) were comparable to those of VF (MD and PSD) and better than those of PVEP (P100 latency and amplitude). In addition, no significant difference was found in the consistency analysis of the qualitative comparison between the icVEP, VF, and PVEP (McNemar p > 0.05). In this study, icVEP showed a diagnostic ability for early to moderate POAG patients comparable to VF and PVEP. IcVEP might be applied as a supplementary psychophysical examination method in addition to VF examinations for special POAG populations who have difficulty cooperating with the VF examination.

Effects of Smoking on Pattern Visual Evoked Potentials

Aim: The aim of the study is to get a better understanding of the side effects of smoking by evaluating the effect of recently elevated smoking rate on Visual Evoked Potentials (VEP) and to determine whether it is necessary to use different normals when evaluating the VEP measurements of smoking patients. Material and Methods: The patients who have applied to our ophthalmology and neurology outpatient clinics during 2021-2022 are included to the study. Detailed ophthalmologic examination of the patients as well as their VEP test is completed followed by a dilated fundus examination assessment. The patients with normal results are included to the study. The smoking rate is calculated on pack/year basis. Pattern VEP (PVEP) recording is performed based on Keypoint (Dantec, Denmark) and International Society for Clinical Electrophysiology of Vision (ISCEV) criteria. Data obtained through the study are analyzed by SPSS 21.0 version software. Countable variables with normal distribution between two independent groups are analyzed with Independent Sample T test whereas variables without normal distribution are analyzed with Mann Whitney U test. Chi-square test is used for comparing categorical variables. Results: 71 patients were included to the study where 33 of them were placed in smoking group and 38 in non-smoking group (control group). Smoking group had a yearly cigarette package consumption of 5.20±8.93 (0.2-40). VEP latency and amplitude changes were compared and according to the obtained results; there was P100 latency prolongation in between left and right eye of the patients in the control group and smoking group but it did not have any statistical significance (p=0.910 and p=0.697 respectively). There was no statistically significant difference in either left nor right eye in terms of smoking and P100 and N70 latencies (p=0.707, p=0.838, p=0.717 and p=0.621 respectively). Similarly, there was no significant correlation between yearly package consumption and P100 and N70 latencies and amplitudes of left and right eyes (p=0.503, p=0.410, p=0.776 and p=0.940 respectively). Conclusion: No significant effect of smoking is found on VEP values thus leading us to believe that the same normal intervals can be used in the evaluation of VEP results of both smoking and non-smoking patients.

Assessment of amblyopic children undergoing occlusion therapy by pattern visual evoked potentials and contrast sensitivity tests.

Background: Amblyopia is a case where one or less commonly, both eyes have impaired visual performance, even with the best optical correction and no visible disease of the visual system. Objectives: To assess contrast sensitivity tests (CST) and pattern visual evoked potentials (PVEP) results in amblyopic children who have already started occlusion therapy for durations ranging from 6 to 12 months. Methods: This cross-sectional study was conducted on 200 eyes of 50 patients with monocular amblyopia and 50 age and sex matched controls. Both patients and controls underwent ophthalmological assessment, PVEP, and CST. Results: There was no statistically significant difference in the results of P100 latencies of qualitative PVEP in amblyopic eyes compared to non-amblyopic eyes and control eyes, while the qualitative CST showed a highly statistically significant difference, being affected in 98% of amblyopic eyes compared to unaffected eyes (4%) and control eyes (4%). The maximum contrast level and minimal contrast level of quantitative CST were significantly lower in amblyopic eyes compared to non-amblyopic and control eyes. The cutoff value of maximal contrast level at mean frequencies of 2.5 ± 0.9 Hz, and a range of (1.1-4.1) for amblyopic eyes is ≤21 dB, while the cutoff value of minimal contrast level at mean frequencies of 13.4 ± 2.6 Hz, and a range of (6.7-18) for amblyopic eyes is ≤12 dB. Conclusion: Detection of amblyopia by CST is a noninvasive and easy procedure, which represents a promising tool to support the diagnosis of amblyopia.

P100 Wave Latency and Amplitude in Visual Evoked Potential Records in Different Visual Quadrants of Normal Individuals.

Assessment of the pattern visual evoked potential (PVEP) responses in different areas of visual fields in individuals with normal vision. This study was conducted on 80 eyes of normal subjects aged 18-35 years. All participants underwent refraction and visual acuity examination. Visual evoked potential (VEP) responses were recorded in different areas of field. The repeated measure test was used to compare the P100 latency and amplitude of PVEP among different areas. The repeated measures analysis of variance showed a statistically significant difference among different areas in terms of amplitude and latency of P100 (P = 0.002 and P 0.001, respectively). According to the results, the highest and lowest amplitude of P100 was observed in inferior-nasal and superior areas, respectively. The highest and lowest latency of P100 was related to the temporal and inferior-nasal areas, respectively. This study partially revealed the details of local PVEP distribution in the visual field and there was a significant difference in the amplitude and latency of PVEP wave in different areas of the visual field.

Factors affecting the severity and prognosis of visual damage in inhalational methanol poisoning.

Inhalational methanol poisoning could cause severe damage to visual function. This study analyzed the prognosis of the correlation between the visual function and the relevant risk factors. In this retrospective study, 14 patients had confirmed inhalational methanol poisoning, resulting in visual impairment in both eyes. The following tests were performed: laboratory tests, best corrected visual acuity (BCVA), intraocular pressure, slit lamp, fundus photography, visual field (VF), pattern visual evoked potential (P-VEP), flash electroretinogram (F-ERG), optical coherence tomography (OCT), and orbital or cranial magnetic resonance imaging (MRI). With active treatment, visual function improved to varying degrees in all 14 cases (28 eyes) in this study. The BCVA of 21 eyes declined to no light perception at the onset; 16 eyes showed different degrees of improvement after treatment, with the final BCVA (LogMar) mainly ranging from 2 to 3, and vision acuity stabilized after the 5th month. The VF pattern in the acute phase was mostly blind. Other VF patterns included the central visual island, large paracentral scotomas, hemipleural VF defects, and the temporal visual island. Retinal nerve fiber layer (RNFL) thickening was observed commonly in the acute phase (146.8 ± 33.2 μm), which subsided in the 1st month, showed dramatic thinning at the 3rd month, and then stabilized in the 5th month after onset. MRI showed that the main sites involved were optic nerve impairment, the optic disk, and retrobulbar segments. The basal ganglia region was the site most involved in the central nervous system (CNS). Inhalational methanol poisoning could lead to severe impairment of visual function, and the prognosis of visual acuity (VA) was highly relevant to the risk factors of duration of toxic exposure, delayed admission, and degree of acidosis.

Clinical Spectrum of Indirect Traumatic Optic Neuropathy in South Indian Subjects Observational Study

Purpose: To report the aetiology, visual outcome, and clinical features of indirect traumatic Optic Neuropathy (TON) patients from the tertiary eye care center in South India. Methods: It is a retrospective and observational study. Details of age, gender, number of days of presentation after injury, Snellen visual acuity at presentation and last follow-up, visual evoked potentials, visual field findings using the Humphrey visual field analyser, associated ocular complications, and mode and time of treatment were obtained from the medical records of all indirect TON patients. Results: Indirect TON patients are mainly young males (94%) and road traffic accident (RTA) (65%) is the main cause of TON, followed by falls (19%) and sport-related activities (11%). Visual acuity loss was severe in more than 50% of the subjects and only 16%% of the patients showed improvement in visual acuity greater than one line. Pattern visual evoked potentials and visual fields are recordable only in 15% of the subjects. Commonly associated ocular complications in indirect TON patients were orbital fracture (43%), lid tear (16%), sub-conjunctival haemorrhage (13.5%), and angle recession (13.5%). Three out of four patients who received methylprednisolone and oral steroids within a week showed an improvement in visual acuity of greater than three lines, while just one patient out of four who received the same medication after a week improved visual acuity of three lines. Conclusion: RTA (road traffic accidents) is the most common cause of indirect TON and mainly young males were the affected individuals. IVMP along with oral steroids within a week, would help TON patients for reasonable visual recovery. Presenting Visual acuity of &gt; 6/600 and recordable pattern VEPs would be the prognostic factors for good visual outcomes in indirect TON patients.

Pattern visual evoked potentials show an inferior-superior topographic shift through maturation in childhood.

The pattern-reversal visual evoked potential (prVEP) is an established routine clinical test. Its objectivity is particularly valuable for assessing visual pathway function in children. International standards specify at a minimum that an active electrode is placed on the occiput at Oz, but we find an additional inferior electrode at the inion (Iz) provides larger and more sensitive prVEPs in young persons. This study assesses the significance and age-dependence of these observations. PrVEPs were recorded from 1487 patients considered ophthalmologically normal aged <20years old, to a range of check widths including International Society for Clinical Electrophysiology of Vision (ISCEV)standard large (50') and small (12.5') check widths. P100 peak-time and amplitude from both electrode sites were analysed. A subset of 256 children were studied longitudinallybyfitting logistic regression models including a random effect on subjects. PrVEPs were largest over the Iz electrode for the majority of infants and children. This transitioned with age to become equal or smaller at Oz as a function of check width. For ISCEV standard large and small check widths, transition periods were ∼8 and ∼12years of age, respectively. We estimated abnormal result classifications of 3.7% with use of an Oz electrode alone, which decreases to 0.0-0.5% when adding or using an Iz electrode. The inferior dominance of prVEP topography in children may be explained by age-related anatomical changes altering the cortical dipole, combined with physiological maturation of the neural generators of the prVEP. We recommend the Iz electrode is used routinely in recording of prVEPs in children. KEY POINTS: Pattern visual evoked potentials (PVEPs) are an established clinical test which provide objective assessment of visual pathway function. These are particularly valuable in providing objective information of vision in children. International standards specify the active recording electrode should be placed at the mid-occiput (Oz), but we find that pattern-reversal visual evoked potential amplitudes are larger for a lower placed electrode (Iz) in young persons. This was assessed in 1487 patients who had simultaneous PVEP recording at both electrode positions, and it was found that the majority of PVEPs in children were larger over the Iz electrode. The developmental differences in PVEP distribution transitioned to be equal between Iz and Oz with increasing age as a function of check width, at ∼8 and ∼12years old for large and small check widths, respectively. These differences will improve diagnostic accuracy of paediatric PVEPs. We hypothesise these changes reflect developmental anatomical and neurophysiological changes altering the PVEP dipole.

Visual evoked potential changes following Botox administration in patients with blepharospasm.

To examine visual evoked potential (VEP) changes following botulinum toxin type A (BTA) administration in patients with blepharospasm. Patients diagnosed with blepharospasm receiving BTA administration were included in the study. Three groups, a control group and two study groups (patients examined 14days after BTA administration-Study Group 1, and patients examined 28days after BTA administration-Study Group 2) were evaluated. Dilated fundus examinations were performed following detailed ophthalmological examinations and VEP tests. Keypoint (Dantec, Denmark) and ISCEV criteria were adopted for pattern VEP (PVEP) recording. BTA was applied in the form of local injections at a total 15-30 units, at 2.5-5 units per injection. A mean 19.4 ± 3.2 units of BTA was used for each eye. N70 (ms), P100 (ms), and P100 (uV) values were statistically significantly lower in both study groups following drug administrations compared to the control group (p < 0.001 for all). Significant positive correlation was observed between increased P100 amplitudes and age in the control group (p = 0.008, r = 0.200). Significant negative correlation was observed between the BTA units used and decreased P100 amplitudes in both study groups 1 and 2 following drug administrations (p = 0.017, r = - 0.180 and p = 0.043, r = - 0.153, respectively). VEP may be an important method in the diagnosis and follow-up of blepharospasm and in determining the success of drug administration and additional therapeutic requirements.

Visual pathway function in untreated individuals with major depression.

Major depression (MD) is the one of the most debilitating diseases, affecting millions of people all around the world. To establish visual pathway function in untreated individuals with MD. In 29 untreated, newly diagnosed, ophthalmologically asymptomatic individuals (58 eyes) with MD (mean age: 47.3 years) and in 29 (58 eyes) of age-, sexand refractive error-matched healthy controls (mean age: 46.8 years), the following examinations were performed: 1) best corrected distance visual acuity (BCDVA); 2) intraocular pressure (IOP); 3) and 4) biomicroscopy of anterior and posterior segment of eye; 5) macular structure (SD-OCT-Zeiss); and 6) pattern visual evoked potentials (PVEPs) measurements according to the International Society for Clinical Electrophysiology of Vision (ISCEV) standard (ISCEV-standard PVEPs). An analysis of correlation between the parameters of PVEPs and the depression severity (Hamilton Depression Rating Scale (HAMD)) was performed. To estimate the diagnostic power of PVEPs test, a receiver operating characteristics (ROC) curve was used. Data were analyzed with the significance level of p < 0.05. In the study group and in healthy control, the clinical results and macular structure were normal and not different. In the MD group, in PVEPs test (check size: 1°4'and 0°16'), a significant decrease of amplitudes of P100 (AP100), associated with prolonged P100 peak time (PTP100; check size: 0°16', p < 0.004) were detected. The most frequent abnormality in PVEPs examination in the MD group was AP100 reduction (in 69% of individuals) detected using stimulation check size 0°16'. The statistically significant positive correlation between PTP100 (check size: 0°16') and HAMD score was found in severe MD (p = 0.03). The analysis of ROC curve revealed the highest sensitivity of 0.759 and specificity of 1.0 for AP100 (0°16'). The area under the curve (AUC) was 0.841 (p < 0.001). In individuals with newly diagnosed, ophthalmologically asymptomatic and untreated MD, a dysfunction of visual pathway is present without other signs of ocular pathology. The visual pathway dysfunction measured with ISCEV PVEPs has a potential value to be an objective biomarker of MD.

ARC/Arg3.1 expression in the lateral geniculate body of monocular form deprivation amblyopic kittens

PurposeThe present study compared the expression of activity-regulated cytoskeleton-associated protein (ARC/Arg3.1) in the lateral geniculate body between form deprivation amblyopia kittens and normal kittens to examine the significance of ARC/Arg3.1 in the lateral geniculate body in the pathogenesis of amblyopia.MethodsTwenty kittens were randomly divided into an experimental group (n = 10) and a control group (n = 10). Black opaque covering cloth was used to cover the right eye of kittens in the experimental group. Pattern visual evoked potentials (PVEP) were detected weekly in all kittens. The expression of the ARC/Arg3.1 gene was detected by immunohistochemistry and in situ hybridization, and apoptosis of lateral geniculate body cells was detected by TUNEL.ResultsPVEP detection showed that at the age of 5 and 7 weeks, the latency of P100 in the right eye of the experimental group was higher than that of the other three groups (P < 0.05), and the amplitude of P100 was lower than that of the other three groups (P < 0.05). The expression of ARC/Arg3.1 protein (P < 0.05) and mRNA (P < 0.05) in the lateral geniculate body of the experimental group was significantly lower than that of the control group. The level of neuronal apoptosis in the experimental group was higher than that in the control group (P < 0.05). The expression of the ARC/Arg3.1 gene was negatively correlated with the apoptosis level of lateral geniculate body neurons.ConclusionsThe expression of ARC/Arg3.1 is associated with monocular form deprivation amblyopia and apoptosis of lateral geniculate body cells.