Clinical application of critical flicker fusion frequency in non-arteritic anterior ischemic optic neuropathy / 中华眼底病杂志

Objective:To investigate the application of critical flicker fusion frequency (CFF) in non-arteritic anterior ischemic optic neuropathy (NAION).Methods:A cross-sectional study. From January 2021 to September 2021, a total of 58 NAION patients (105 eyes) (NAION group) and 33 cases (63 eyes) in the healthy control (HC) group were included from Department of Ophthalmology of First Medical Center, PLA General Hospital. Patients underwent best-corrected visual acuity (BCVA), optical coherence tomography (OCT), visual field, CFF and flash visual evoked potential (F-VEP) examinations. BCVA examination was performed using a Snellen decimal visual acuity chart and was converted to logarithm of the minimum angle of resolution visual acuity. In the affected eyes group, there were 56 cases (72 eyes), 31 cases (43 eyes) male and 25 cases (29 eyes) female, with an average age of 49.28±11.42 years old. And the affected eyes were divided into 4 groups: <1, 1-<3, 3-<6 and >6 months according to the time interval from onset to CFF examination, which were 20(27.8%), 26 (36.1%), 17 (23.6%) and 9 (12.5%) eyes, respectively. According to the BCVA ≥0.5, 0.1-0.5, <0.1 in CFF examination, the affected eyes were divided into a mild, moderate, and severe degree, 33 (45.8%), 32(44.4%) and 7 (9.8%) eyes, respectively. Sixty-three eyes of 33 cases were in the HC group. There were 17 cases(31 eyes) males and 16 cases (32 eyes) females, with an average age of 35.18±10.96 years. Hand-held CFF detector type 2 (Japan, NEITZ company) was used for the CFF examination. The thickness of peripheral retinal nerve fiber layer (pRNFL), macular inner limiting membrane retinal pigment epithelium (mILM-RPE), F-VEP peak time and peak value and mean visual field defect (MD) values were recorded within 1 week of CFF examination. The CFF value of the above subgroups was analyzed in order using one-way ANOVA. Pearson correlation analysis was used for the correlation between CFF and F-VEP peak time, peak value, BCVA and MD. The correlations between BCVA, visual field, F-VEP, and CFF were analyzed.Results:The trichromatic values of red, green and yellow in NAION affected eyes were 22.56±10.30, 24.10±11.51, 24.81±11.41 Hz, respectively, which was significantly reduced compared with the HC group ( t=-10.53,-11.11,-11.36; P<0.05). There was no significant difference in CFF-red, green, and yellow values at different time points after the onset of the disease ( F=2.075, 1.893, 2.073; P>0.05). Compared CFF-red, green, and yellow values in NAION-affected eyes with different degrees, the difference was statistically significant ( F=31.579, 27.332, 32.055; P<0.05). The results of correlation analysis showed that the peak time of F-VEP ( r=-0.362, -0.379,-0.357; P<0.05), BCVA ( r=-0.705,-0.695,-0.714; P<0.05), and which was negatively correlated with CFF three color. MD and CFF were positively correlated ( r=0.486, 0.435, 0.450; P<0.05). Conclusion:The CFF value of the affected eye is decreased significantly in NAION-affected eyes, and CFF is more sensitive than F-VEP in reflecting visual impairment, and has a good correlation with visual function and latency of F-VEP.

A recuperação da memória operacional visual não é afetada por flicker cromático / The retrieval from visual working memory is not affected by chromatic flicker / La recuperación de la memoria operativa visual no es afectada por el flicker cromático

Nós investigamos o efeito da informação visual irrelevante (IVI) na recuperação da informação na memória de trabalho. Os participantes realizaram uma tarefa de reconhecimento visual. Em metade das provas, uma dica retroativa espacial foi apresentada no intervalo de retenção. A IVI, um flicker cromático, com frequências de 1,0 Hz, 7,3 Hz e 15,3 Hz, foi apresentada no intervalo entre dica e teste. A dica melhorou a acurácia e a rapidez na tarefa de reconhecimento. O flicker não afetou o desempenho. A dica retroativa pode permitir a recuperação da informação para um estado ativo e pode tê-la protegido da interferência do flicker.

We investigated the effect of irrelevant visual information (IVI) on retrieving information from working memory. Participants performed a visual recognition task. In half of the trials, a retroactive spatial cue was presented in the retention interval. The IVI, a chromatic flicker, with frequencies of 1.0 Hz, 7.3 Hz, and 15.3 Hz, was presented in the interval between cue and test. The cue improved the accuracy and speed of the recognition task. The flicker did not affect performance. The retroactive cue may allow the retrieval of information to an active state and may have protected it from the flicker interference.

Nosotros investigamos el efecto de la información visual irrelevante (IVI) en la recuperación de información de la memoria operativa. Los participantes realizaron una tarea de reconocimiento visual. En mitad de las pruebas, se presentó una pista espacial retroactiva en el intervalo de retención. El IVI, un flicker cromático, con frecuencias de 1,0 Hz, 7,3 Hz y 15,3 Hz, se presentó en el intervalo entre pista y prueba. La pista mejoró la precisión y la velocidad de la tarea de reconocimiento. El flicker no afectó el performance. La pista puede permitir la recuperación de la información a un estado activo y puede haberla protegido de la interferencia del flicker.

Macular Pigment Optical Density in the Korean Population: a Cross Sectional Study

50 years) showed lower MPOD than younger (30–49 years) subjects. But, in the healthy population, the estimated MPOD values exhibited a decreasing trend with age, but there were no significant differences according to age, after excluding patients with AMD. MPOD was significantly lower in patients with AMD than in aged healthy controls. Furthermore, hypertension, dyslipidemia, and smoking were identified as risk factors for AMD.CONCLUSION: MPOD measured with MPSII® reflects the MP density in healthy individuals and patients with dry AMD. Aging was not significantly associated with low MPOD in healthy population, but the presence of dry AMD was significantly associated with low MPOD. Then, low MPOD may be a risk factor for development of dry AMD. Furthermore, routine screening with MPS II® for ages 50 and older is thought to help detect early low MPOD and identify individuals who should take supplements.

Effects of the Photovoltaic Distributed Generation on Electricity Distribution System Voltage - Updated Review

ABSTRACT Concerns about the environment and a growing demand for electricity have led to the intensive search for renewable energy sources. Photovoltaic solar energy, in the form of distributed generation, has shown a very high growth rate to an extent that in some regions it will be adopted on a large scale, thus being responsible for the supply of a significant portion of the load of this region. Some factors have favored the adoption of distributed generation: the drop in the price of solar panels and inverters, as well as its easy installation and maintenance. However, the large-scale adoption of solar distributed generation brings new challenges to the power distribution system. Network voltage control is an example. In conventional systems, voltage control is a properly addressed problem, but in networks with the presence of distributed generation, where at certain times of the day reverse energy flows can be observed, more detailed studies on voltage behavior are necessary concerning the power quality. This article makes an analysis of relevant studies on the effects that the insertion of photovoltaic distributed generation can cause in the voltage of the electric power distribution system under the optics of two phenomena: the fluctuation and the voltage ripple.

Comparative study on common diagnostic methods for covert hepatic encephalopathy / 中华消化杂志

Objective To evaluate clinical application value of critical flicker frequency (CFF),psychometric hepatic encephalopathy score (PHES) and Stroop test in the diagnosis of covert hepatic encephalopathy (CHE).Methods A total of 110 patients with decompensated liver cirrhosis and 54 individuals without liver diseases were enrolled as control group.According to PHES＜-4 points as reference threshold for CHE,the threshold of CFF and time of Stroop test for CHE diagnosis was caculated.Positive results of at least two of PHES,CFF and Stroop tests was considered as the gold standard for CHE diagnosis,and then the value of these three methods in CHE diagnosis was evaluated.Student's t test and receiver operating characteristic curve (ROC) were used for statistical analysis.Results Among the 110 patients with liver cirrhosis,40 patients had no hepatic encephalopathy (HE0),52 patients had CHE,and 18 patients had grade 2 hepatic encephalopathy (HE2).The CFF value and total time of Stroop test of control group were (43.70±1.92) Hz and (201.17±20.65) s,respectively.The CFF value of HE0 group was (41.40 ± 1.85) Hz,which was higher than that of CHE group ((38.33 ± 2.32) Hz),and the difference was statistically significant (t=-7.116,P＜0.01).The total time of Stroop test of HE0 group was (197.91±26.68) s,which was shorter than that of CHE group ((253.24± 33.33) s),and the difference was statistically significant (t=8.936,P＜0.01).When PHES＜-4 points was considered as a reference threshold of CHE,the threshold of CFF for CHE diagnosis was 39 Hz,the sensitivity was 94.9％ and the specificity was 73.1％,the area under the curve (AUC) was 0.879.The threshold of the total time of Stroop test for CHE diagnosis was 233.80 s,the sensitivity was 83.3 ％ and the specificity was 71.1％,the AUC was 0.803.The completion time of the number connection test (NCT)-A,NCT-B and digit symbol test (DST),which were there of five subtests of PHES,of CHE group were (80.27±36.05) s,(124.18±55.96) s and (25.03±8.23) s,respectively,compared with those of HE0 patients ((56.68±18.82) s,(80.00±25.58) s and (34.68±8.75) s,respectively),the differences were statistically significant (t =3.691,4.108 and-4.780;all P＜0.01).Compared with the results of combined PHES and Stroop test in the diagnosis of HE0,CHE and HE2,the consistency rates of CFF＜39 Hz as threshold for diagnosis were 95.0％,61.5％ and 100.0％,respectively.Conclusions NCT-A,NCT-B and DST three subtests of PHES have higher efficiency in CHE diagnosis.CFF and Stroop test are also reliable screening methods for CHE,with advantage of objectivity and high specificity.

Effect of Selective Serotonin Reuptake Inhibitors on Psychomotor Function in Patients of Depression: A Comparative Study of Sertraline and Fluoxetine.

Aims and objectives: Depression is a most common and widespread of all psychiatric disorders. Treatment of depression includes the use of antidepressants, commonly used clinically, such as tricyclic antidepressants, selective serotonin reuptake inhibitors, selective norepinephrine reuptake inhibitor, and monoamine oxidase inhibitors. Certain antidepressants apart from improvement in the symptoms found to have detrimental effect on cognitive and psychomotor functions. Objective of this study was to assess and to compare the effect of sertraline and fluoxetine on cognitive and psychomotor functions. Materials and methods: Effect of sertraline and fluoxetine on psychomotor function was assessed by using critical flicker fusion frequency (CFF) and reaction time (RT) in patients of mild to moderate depression at the end of 2nd and 4th week of mono therapy. Results: Patients in both the group have their RT remained significantly higher (p < 0.001) in comparison with control and CFF remained significantly lower at the end of both the week except sertraline group in which CFF did not differ significantly from control at the end of 4th week. There was a significant rise in CFF (p < 0.05) in sertraline group as compared to fluoxetine. Sertraline showed a significant improvement (p < 0.01) in visual reaction time (VRT) at both the follow-ups and auditory reaction time (ART) (p < 0.01) at 4th week of monotherapy. Both the groups did not differ with respect to their effect on choice reaction time (CRT). Conclusion: Findings of this study support the use of sertraline which had shown less impairment of psychomotor function in patients of depression as compared to fluoxetine, in special subgroups of population who operate machinery, drive vehicle or require alertness for the work.

Lateral interactions in visual perception of temporal signals: cortical and subcortical components

The aim of this work was to isolate and investigate subcortical and cortical lateral interactions involved in flicker perception. We quantified the perceived flicker strength (PFS) in the center of a test stimulus which was simultaneously modulated with a surround stimulus (50 percent Michelson contrast in both stimuli). Subjects were requested to adjust the modulation depth of a separate matching stimulus that was physically identical to the center of the test stimulus but without the surround. Using LCD goggles, synchronized to the frame rate of a CRT screen, the center and surround could be presented monoptically or dichoptically. In the monoptic condition, center-surround interactions can have both subcortical and cortical origins. In the dichoptic condition, center-surround interactions cannot occur in the retina and the LGN, therefore isolating a cortical mechanism. Results revealed both a strong monoptic (subcortical plus cortical) lateral interaction and a weaker dichoptic (cortical) lateral interaction. Subtraction of the dichoptic from the monoptic data revealed a subcortical mechanism of the lateral interaction. While the modulation of the cortical PFS component showed a low-pass temporal-frequency tuning, the modulation of the subcortical PFS component was maximal at 6 Hz. These findings are consistent with two separate temporal channels influencing the monoptic PFS, each with distinct lateral interactions strength and frequency tuning characteristics. We conclude that both subcortical and cortical lateral interactions modulate flicker perception.

Research on Comprehensive Assessment Method of Mental Fatigue in Monitoring Task / 航天医学与医学工程

Objective To study the relationship between eye movement,HRV indexes and mental fatigue,find feasible objective indexes and build the comprehensive method to evaluate mental fatigue.Methods When twenty subjects executed the simulated monitoring task for 60 min,pupil diameter and ECG data were recorded by eye tracker system and Holter.The subjects were divided into 2 groups(fatigued group/scarcely fatigued group) according CFF(critical flicker frequency) and reaction time(RT).Based on comparison of various indexes between pre-and post-monitoring task,potent indexes were extracted to evaluate mental fatigue.Results After monitoring task,the change of fatigue feeling,Perclos,r-MSSD,PNN50,HF,LF and TP were significantly different in two groups.Conclusion It's suggested that psychology,Perclos and HRV indexes can be used to build the multilevel comprehensive method which can detect mental fatigue quantitatively and qualitatively.

Subjective Symptoms and Flicker Test Values in Relation to Chronic Low Dose Organic Solvent Exposure / 예방의학회지

This study was conducted to examine the effect of chronic low dose organic solvent exposures in the industries towards then neurobehavioral functions of workers subjective symptoms on neurobehavioral function as well as a visual reaction time test (Flicker test) were administered to 94 exposed and 162 unexposed workers in a oil refinery and some other auto-repair shops. The results obtained were as follows: 1. Symptom complaints were higher and Flicker test values were lower in exposed workers than in unexposed workers. 2. Flicker values were inversely correlated with urinary Hippuric acid concentration in exposed workers (r=-0.26, p<0.05). 3. Flicker values were inversely correlated with subjective symptom score (r=-0.15, p<0.05). Low Flicker value were also related with some subjective symptoms such as "Dimmed vision", "Nightmare", "weakness on extremity" in workers as a whole. While symptoms of "Dimmed vision", "Nightmare" only observed among exposed workers.

APPLICATION OF CT AND MRI FUSION IMAGE TECHNOLOGY IN CRANIOFACIAL REGION / 解放军医学杂志

To achieve the fusion of cranio-jaw-facial CT and MRI image,the single value decomposition-iterative closest point method based on contour feature and the multiresolution method based on wavelet pyramid were used.The results showed that the fusion was operated easily and promptly,its images were satisfactory and its reliability was good. The fusion of cranio-jaw-facial CT and MRI image was obtained. It suggested that the fusion of cranio-jaw-facial CT and MRI image was feasible in clinical practice. It can provide the image basis helping the analysis of diagnosis and treatment for diseases of the cranio-jaw-facial region with complicated anatomical formation.