Spectral Domain Optical Coherence Tomography of Vogt-Koyanagi-Harada Disease: Novel Findings and New Insights into the Pathogenesis

Objective To provide novel spectral domain optical coherence tomography (SD OCT) findings of Vogt-Koyanagi-Harada (VKH) disease as well as new insights into the pathogenesis of this disease. Methods Detailed SD OCT and fluorescein angiography (FA) findings of 18 consecutive VKH patients (11 women and 7 men) from December 2007 to April 2009 who were in acute uveitic stage at presentation were reviewed. All the patients had been followed up for at least 6 months with reevaluation(s) of SD OCT performed in 10 patients. Results Intraretinal cysts were found to be located in various layers of the outer retina. In addition to the photoreceptor layer, they could also be found between the outer plexiform layer and the outer nuclear layer, or spanning the external limiting membrane. On FA, intraretinal cysts could be hypofluorescent, normofluorescent, or hyperfluorescent. Some intraretinal cysts had a characteristic FA pattern, in which a small round hypofluorescent area was surrounded by a ring of hyperfluorescence (donut-shaped dye pooling). Subretinal fibrinoid deposit appeared in acute uveitic stage in two severe VKH patients and seemed to develop from subretinal exudates and evolved into typical subretinal fibrosis. Gradual transfiguration/migration and progressive proliferation/pigmentation of the subretinal fibrinoid deposit/subretinal fibrosis was observed in one patient. Conclusions Intraretinal cysts could form in various layers of the outer retina and may result from extension of choroidal inflammation. Subretinal fibrosis may develop from subretinal exudates in VKH patients and may cause substantial visual impairment.

Spectral domain optical coherence tomography crosssectional image of optic nerve head during intraocular pressure elevation

AIM: To analyze changes of the optic nerve head(ONH) and peripapillary region during intraocular pressure(IOP) elevation in patients using spectral domain optical coherence tomography(SD-OCT).METHODS: Both an optic disc 200×200 cube scan and a high-definition 5-line raster scan were obtained from open angle glaucoma patients presented with monocular elevation of IOP(≥30 mm Hg) using SD-OCT. Additional baseline characteristics included age, gender, diagnosis,best-corrected visual acuity, refractive error, findings of slit lamp biomicroscopy, findings of dilated stereoscopic examination of the ONH and fundus, IOP, pachymetry findings, and the results of visual field.RESULTS: The 24 patients were selected and divided into two groups: group 1 patients had no history of IOP elevation or glaucoma(n =14), and group 2 patients did have history of IOP elevation or glaucoma(n =10). In each patient, the study eye with elevated IOP was classified into group H(high), and the fellow eye was classified into group L(low). The mean deviation(MD)differed significantly between groups H and L when all eyes were considered(P =0.047) and in group 2(P =0.042), not in group 1(P =0.893). Retinal nerve fiber layer(RNFL) average thickness(P =0.050), rim area(P =0.015),vertical cup/disc ratio(P =0.011), cup volume(P =0.028),inferior quadrant RNFL thickness(P =0.017), and clockhour(1, 5, and 6) RNFL thicknesses(P =0.050, 0.012, and0.018, respectively), cup depth(P =0.008), central prelaminar layer thickness(P =0.023), mid-inferior prelaminar layer thickness(P =0.023), and nasal retinal slope(P =0.034)were significantly different between the eyes with groups H and L.CONCLUSION:RNFLaveragethickness,rim area,vertical cup/disc ratio, cup volume, inferior quadrant RNFL thickness, and clock-hour(1, 5, and 6) RNFL thicknesses significantly changed during acute IOP elevation.

Microperimetry and spectral domain optical coherence tomography in myelinated retinal nerve fibers

Dear Sir,I write to present the correlation between microperimetric （MP） values and the density of myelinated retinal nerve fibers （MNFs） in optical coherence tomography （OCT） imaging.

Agreement of angle closure assessments between gonioscopy, anterior segment optical coherence tomography and spectral domain optical coherence tomography

AIM: To determine angle closure agreements between gonioscopy and anterior segment optical coherence tomography(AS-OCT), as well as gonioscopy and spectral domain OCT(SD-OCT). A secondary objective was to quantify inter-observer agreements of AS-OCT and SD-OCT assessments.METHODS: Seventeen consecutive subjects(33 eyes)were recruited from the study hospital’s Glaucoma clinic.Gonioscopy was performed by a glaucomatologist masked to OCT results. OCT images were read independently by 2 other glaucomatologists masked to gonioscopy findings as well as each other’s analyses of OCT images.RESULTS: Totally 84.8% and 45.5% of scleral spurs were visualized in AS-OCT and SD-OCT images respectively(P 【0.01). The agreement for angle closure between AS-OCT and gonioscopy was fair at k =0.31(95% confidence interval, CI: 0.03-0.59) and k =0.35(95%CI: 0.07-0.63) for reader 1 and 2 respectively. The agreement for angle closure between SD-OCT and gonioscopy was fair at k =0.21(95% CI: 0.07-0.49) and slight at k =0.17(95% CI: 0.08-0.42) for reader 1 and 2 respectively. The inter-reader agreement for angle closure in AS-OCT images was moderate at 0.51(95% CI: 0.13-0.88). The inter-reader agreement for angle closure in SD-OCT images was slight at 0.18(95% CI: 0.08-0.45).CONCLUSION: Significant proportion of scleral spurs were not visualised with SD-OCT imaging resulting in weaker inter-reader agreements. Identifying other angle landmarks in SD-OCT images will allow more consistent angle closure assessments. Gonioscopy and OCT imaging do not always agree in angle closure assessments but have their own advantages, and should be used together and not exclusively.

Comment on “The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography”

Dear Editor,We have read and reviewed the article entitled＂The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography＂by Zhao et al^（[1]）with great interest.

Systematic review of macular ganglion cell complex analysis using spectral domain optical coherence tomography for glaucoma assessment

AIM: To review the use of spectral domain optical coherence tomography(SD-OCT) for macular retinal ganglion cells(RGC) and ganglion cell complex(GCC) measurement in glaucoma assessment, specifically for early detection and detection of disease progression. METHODS: A systematic review was performed by searching Pub Med, Medline, and Web of Science for articles published in English through July 2014 describing the various macular SD-OCT scanning strategies developed for glaucoma assessment. The review focused on papers evaluating the use of macular RGC/GCC SDOCT to detect early glaucoma and its progression. The search included keywords corresponding to the index test(macular ganglion cell/RGC/GCC/Spectral domain OCT), the target condition(glaucoma), and diagnostic performance. The RGC/GCC SD-OCT scanning strategies used to assess glaucoma of most commonly used SD-OCT instruments were described and compared. These included the Cirrus high definition-OCT(Carl Zeiss Meditec, Inc., Dublin, CA, United States), RTVue(Optovue, Inc., Fremont, CA, United States), Spectralis(Heidelberg Engineering, Heidelberg, Germany) and the 3D OCT 2000(Topcon Corporation, Tokyo, Japan). Studies focusing on the ability of RGC/GCC SD-OCT to detect early glaucomatous damage and on the correlation between glaucomatous progression and RGC/GCC measurement by SD-OCT were reviewed.RESULTS: According to the literature, macular RGC/GCC SD-OCT has high diagnostic power of preperimetric glaucoma, reliable discrimination ability to differentiate between healthy eyes and glaucomatous eyes, with good correlation with visual filed damage. The current data suggests that it may serve as a sensitive detection tool for glaucomatous structural progression even with mild functional progression as the rate of change of RGC/GCC thickness was found to be significantly higher in progressing than in stable eyes. Glaucoma assessment with RGC/GCC SD-OCT was comparable with and sometimes better than circumpapillary retinal nerve fiber layer thickness measurement.CONCLUSION: An increasing body of evidence supports using macular RGC/GCC thickness as an indicator for early glaucoma. This might be a useful tool for monitoring disease progression.

Choroidal Analysis of Polypoidal Choroidal Vasculopathy by Spectral Domain Optical Coherence Tomography

Purpose: This study was designed to measure the changes in the subfoveal choroidal thickness(SFCT) and choroidal maximal vessel diameter(MVD) of the affected and unaffected fellow eyes in patients with polypoidal choroidal vasculopathy(PCV) and compare them to healthy controls.Methods: In this cross-sectional observational clinical study,SFCT and MVD were measured in both eyes of 53 patients with unilateral PCV. PCV eyes were subgrouped into group A and unaffected fellow eyes into group B. All patients were diagnosed with PCV by fundus fluorescein angiography.(FFA)and indocyanine green angiography.(ICGA). Sixty age- and gender-matched healthy subjects were enrolled in the control group(group C).Results: No statistical difference was observed among groups in age and gender. Overall, SFCT was correlated with MVD in all subjects(P <0.001; correlation coefficient: 0.759). P values were < 0.001 with a correlation coefficient of 0.686,0.801, and 0.808 in groups A, B, and C, respectively. No statistical significance was noted in SFCT among groups A(266.45±99.51 μm),B(269.57 ± 105.10 μm),and C(243.83±99.68 μm)(P =0.335). However, the MVD in group A was(202.55±72.45 μm), significantly larger than that in group C(166.45 ±56.18 μm,P =0.008), while the MVD in group B(194.75±85.27 μm) was equally significantly greater than that in group C(166.45 ± 56.18 μm)(P=0.038).Conclusion: For both PCV patients and healthy subjects,SFCT was positively correlated with MVD. No statistical significance was noted in SFCT between PCV eyes and unaffected fellow / normal eyes. However, MVD was significantly larger in the PCV affected eyes than in unaffected fellow or normal control eyes, suggesting that MVD could be considered as a sensitive indicator to evaluate choroidal perfusion in PCV patients.

Direct spectral domain decomposition method for 2D incompressible Navier-Stokes equations

An efficient direct spectral domain decomposition method is developed coupled with Chebyshev spectral approximation for the solution of 2D, unsteady and in- compressible Navier-Stokes equations in complex geometries. In this numerical approach, the spatial domains of interest are decomposed into several non-overlapping rectangu- lar sub-domains. In each sub-domain, an improved projection scheme with second-order accuracy is used to deal with the coupling of velocity and pressure, and the Chebyshev collocation spectral method （CSM） is adopted to execute the spatial discretization. The influence matrix technique is employed to enforce the continuities of both variables and their normal derivatives between the adjacent sub-domains. The imposing of the Neu- mann boundary conditions to the Poisson equations of pressure and intermediate variable will result in the indeterminate solution. A new strategy of assuming the Dirichlet bound- ary conditions on interface and using the first-order normal derivatives as transmission conditions to keep the continuities of variables is proposed to overcome this trouble. Three test cases are used to verify the accuracy and efficiency, and the detailed comparison be- tween the numerical results and the available solutions is done. The results indicate that the present method is efficiency, stability, and accuracy.

Comparing imaging capabilities of spectral domain and swept source optical coherence tomography angiography in healthy subjects and central serous retinopathy

Background:There are two forms of system implementation of optical coherence tomography angiography(OCTA)in ophthalmic imaging,i.e.,spectral domain(SD-)and swept source OCTA(SS-OCTA).The purpose of this paper is to compare the SD-OCTA and SS-OCTA for elucidating structural and vascular features associated with central serous retinopathy(CSR),and to evaluate the effects of CSR on SD-and SS-OCTA’s imaging capabilities.Methods:Normal subjects and CSR patients were imaged by SD-and SS-OCTA using 3×3 mm and 6×6 mm scan patterns.OCT signal strengths at the superficial retina,deep retina,Sattler’s layer and Haller’s layer were used to compare the ability of SD-and SS-OCTA to image structural features.In addition,the ability to acquire angiograms were discussed by evaluating retinal vessel density.Central serous volume(CSV)was measured and it was correlated with difference in signal strengths(ΔS)between two OCTA devices.Results:Seven normal eyes and seven diseased eyes were recruited.Results showed no significant differences between SD-and SS-OCT in detecting structural features of the retinal layer according to the paired t-test.However,when imaging the Sattler’s layer for normal eyes,a significant difference is found between SD-and SS-OCT(p<0.0001 for 3×3 mm scan,and p=0.0002 for 6×6 mm);while for CSR eyes,the corresponding values were p<0.0001 and p=0.0003,respectively.At Haller’s layer for normal eyes,the corresponding values were p=0.0004 and p=0.0014;and for CSR eyes,p=0.0004 and p<0.0001,respectively.A strong correlation betweenΔS and CSV was observed in the Sattler’s layer(3×3 mm–p=0.0031 and R^(2)=0.951;6×6 mm–p=0.0075 and R^(2)=0.911)and Haller’s layer(3×3 mm–p=0.0026 and R^(2)=0.955;6×6 mm–p=0.0013 and R^(2)=0.972).Conclusions:The results suggest no differences between SD-and SS-OCTA for imaging the retinal layers however,when imaging beyond retinal layers,SS-OCTA appears advantageous in detecting returning signals.In CSR cases,the CSV may have an impact on sub-CSR tissue imaging and appears to have more impact on SD-than SS-OCTA.

Numerical Study on Spectral Domain Optical Coherence Tomography Spectral Calibration and Re-Sampling Importance

A spectral calibration technique, a data processing method and the importance of calibration and re-sampling methods for the spectral domain optical coherence tomography system were numerically studied, targeted to optical coherence tomography （OCT） signal processing implementation under graphics processing unit （GPU） architecture. Accurately, assigning the wavelength to each pixel of the detector is of paramount importance to obtain high quality images and increase signal to noise ratio （SNR）. High quality imaging can be achieved by proper calibration methods, here performed by phase calibration and interpolation. SNR was assessed employing two approaches, single spectrum moving window averaging and consecutive spectra data averaging, to investigate the optimized method and factor for background noise reduction. It was demonstrated that the consecutive spectra averaging had better SNR performance.

Iterative sparse reconstruction of spectral domain OCT signal

We propose and study an iterative sparse reconstruction for Fourier domain optical coherence tomography （FD OCT） image by solving a constrained optimization problem that minimizes L-1 norm. Our method takes the spectral shape of the OCT light source into consideration in the iterative image reconstruction procedure that allows deconvolution of the axial point spread function from the blurred image during reconstruction rather than after reconstruction. By minimizing the L-1 norm, the axial resolution and the signal to noise ratio of image can both be enhanced. The effectiveness of our method is validated using numerical simulation and experiment.

Comparison of ultrasound biomicroscopy and spectraldomain anterior segment optical coherence tomography in evaluation of anterior segment after laser peripheral iridotomy

AIM：To quantitatively assess narrow anterior chamber angle using spectral-domain anterior segment optical coherence tomography（SD-AS-OCT） and ultrasound biomicroscopy（UBM）,and to evaluate the correlations and consistency between SD-AS-OCT and UBM.· METHODS：Fifty-five eyes from 40 patients were examined.Patients were diagnosed with primary angleclosure glaucoma（PACG） remission（11 eyes from 8patients）,primary angle closure（PAC,20 eyes from 20patients） and PAC suspect（24 eyes from 12 patients）.Each eye was examined by SD-AS-OCT and UBM after laser peripheral iridotomy（LPI）.The measurements of SD-AS-OCT were angle open distance（AOD）,anterior chamber angle（ACA）,trabecular iris angle（TIA）,and trabecular iris space area（TISA）.UBM measurements were AOD and TIA.Correlations of AOD500 and TIA500 between UBM and AS-OCT were assessed.All parameters were analysed by SPSS 16.0 and MedCalc.· RESULTS：ACA,TIA and AOD measured by SD-ASOCT reached a maximum at the temporal quadrant and minimum at the nasal quadrant.Group parameters of AOD500 and AOD750 showed a linear positive correlation,and AOD750 had less variability.UBM outcomes of AOD500 and TIA500 were significantly smaller than those of SD-AS-OCT.The results of the two techniques were correlated at the superior,nasal and inferior quadrants.CONCLUSION：Both UBM and SD-AS-OCT are efficient tools for follow-up during the course of PACG.We recommended using parameters at 750 μm anterior to the sclera spur for the screening and follow-up of PACG and PAC.The two methods might be alternatives to each other.

Importance of 3-D image reconstruction of spectraldomain OCT on outcome of grid laser photocoagulation for diffuse diabetic macular edema

AIM:To present the outcome of modified grid laser photocoagulation(GLP)in diffuse diabetic macular edema(DDME)in eyes without extrafoveal and/or vitreofoveal traction.METHODS:Inclusion criteria for the retrospective study were DDME eyes of patients with typeⅡdiabetes mellitus that had≥4 months of follow-up following GLP.Only one eye per patient was analyzed.Using 3-D spectral-domain optical coherence tomography(3-D SDOCT),eyes that had either extrafoveal or vitreofoveal traction,or had been previously treated by an intravitreal medication(s)were excluded.Treated DDME eyes were divided into 4 groups:A)"Classic"DDME that involved the central macula;B)edema did not involve the macular center;C)eyes associated with central epiretinal membrane(ERM);D)DDME that was associated with macular capillary dropout≥2 disc-diameter(DD).RESULTS:GLP outcome in 35 DDME eyes after 4-24(mean,13.1±6.9)months was as follows:Group A)18eyes with"classic"DDME.Following one or 2(mean,1.2)GLP treatments,best-corrected visual acuity(BCVA)improved by 1-2 Snellen lines in 44.4%(8/18)of eyes,and worsened by 1 line in 11.1%(2/18).Central macular thickness(CMT)improved by 7%-49%(mean,26.6%)in77.8%(14/18)of eyes.Causes of CMT worsening(n=4)were commonly explainable,predominantly(n=3)associated with emergence of extrafoveal traction,5-9months post-GLP.Group B)GLP(s)in DDME that did not involve the macular center(n=6)resulted in improved BCVA by 1-2 lines in 2 eyes.However,the central macula became involved in the edema process after the GLP in 3(50%)eyes,associated with an emergence of extrafoveal traction in one of these eyes 4months following the GLP.Group C)GLP failed in all 5eyes associated with central ERM.Group D)GLP was of partial benefit in 2 of 6 treated eyes with macular capillary dropout≥2DD.CONCLUSION:Eyes with DDME that involved the macular center were found to achieve favourable outcomes after GLP(s)during mid-term follow-up,unless complicated pre-GLP or post-GLP by vltreoretinal interface abnormalities,often extrafoveal traction or ERM,or by capillary dropout≥2DD.Prospective studies with larger cohorts are required.

A SPECTRAL-DOMAIN IMMITTANCE APPROACH FOR THE CHARACTERISTICS OF FINLINES LOADED WITH ANISOTROPIC MEDIUM

The equations of electrodynamics for a gyrotropic medium by using Maxwell’s equa-tions are deduced.Through Fourier transformation,the admittances of TM and TE modes inthe electrically gyrotropic substrate and magnetically gyrotropic substrate are given.Numericalresults of the dominant mode in magnetized ferrite-loaded double-layered finlines are presentedwhich could be used in designing finline ferrite devices.

Comparison of central macular thickness between two spectral-domain optical coherence tomography in elderly non-mydriatic eyes

AIM: To compare central macular thickness (CMT) measurements obtained by two spectral-domain optical coherence tomography (SD-OCT) exams, and to evaluate measurement reproducibility and agreement between these two exams, and to investigate the relationship between CMT and possible influencing factors such as age, sex, eye (OD/OS), and operators in elderly non-mydriatic eyes. METHODS: Seventy-two normal subjects were included. Every subject underwent CMT measurement twice using one of two SD-OCT (OSE-2000, Moptim, Shenzhen, China & 3-D OCT-1000, Topcon, Tokyo, Japan) instruments respectively where we randomly chose one eye in each patient for the test; these exams were performed by two operators over an hour period with a brief rest between sessions. Comparison of the OSE-2000 and 3-D OCT-1000 CMT measurements was based on paired- t test The mean difference between the CMT measurements was calculated. General linear model analyzed the relationships among eye (OD/OS), operator, sex, and CMT values using age as co-variant. All tests were considered statistically significant at P <0.05. The main outcome measures included CMT. RESULTS: When evaluated with general linear model analysis, CMT measurements were found to have high reproducibility across the two instruments between the two operators for the OSE-2000 single line scan and 3-D OCT-1000 macular scans (P=0.731; P=0.443). There was statistically significant difference in CMT values between the two instruments (P<0.001) and the mean difference was -46.83 mu m at 95% confidence limits (-49.15,-44.51). Age was positively correlated with CMT (beta coefficient =0.516, P=0.001; beta coefficient=0.453, P =0.009) and sex was correlated with CMT from the OSE-2000 (P=0.021) but not with the 3-D OCT-1000 (P=0.056). According to the actual thickness measurements, the CMT of the male was thicker than the female's but there was no statistical difference. There was interaction between sex and eye in OSE-2000 and not in 3-D OCT-1000 (P=0.02; P =0.374). No significant correlation was found between CMT and the influencing factor of eye in both of the instruments (P=0.884; P=0.492). CONCLUSION: Reproducibility of CMT measurement using the two SD-OCTs is excellent in normal eyes according to the operator factor analysis. OSE-2000 has a different posterior retinal boundary of CMT measurement, which results in the CMT value differences, compared with the 3-D OCT-1000. Age is positively correlated with CMT measurement while sex is correlated with CMT in the OSE-2000 but not in the 3-D OCT-1000 and eye (OD/OS) had no correlation with CMT values. Mydriatic drops may not be necessary for CMT measurement using high scan rate SD-OCT in normal eyes in dark room.

A Service-Based Intelligent Time-Domain and Spectral-Domain Flow Aggregation in IP-over-EON Based on SDON

The rapid growth of IP traffic has contributed to wide deployment of optical devices in elastic optical network.However,the passband shape of wavelength selective switches(WSSs)that are used in reconfigurable optical add-drop multiplexer(ROADM)/optical cross connect(OXC)is not ideal,causing the narrowing of spectrum.Spectral narrowing will lead to signal impairment.Therefore,guard-bands need to be inserted between adjacent paths which will cause the waste of resources.In this paper,we propose a service-based intelligent aggregation node selection and area division(ANS-AD)algorithm.For the rationality of the aggregation node selection,the ANS-AD algorithm chooses the aggregation nodes according to historical traffic information based on big data analysis.Then the ANS-AD algorithm divides the topology into areas according to the result of the aggregation node selection.Based on the ANS-AD algorithm,we propose a time-domain and spectral-domain flow aggregation(TS-FA)algorithm.For the purpose of reducing resources'waste,the TS-FA algorithm attempts to reduce the insertion of guard-bands by time-domain and spectral-domain flow aggregation.Moreover,we design a time-domain and spectral-domain flow aggregation module on software defined optical network(SDON)architecture.Finally,a simulation is designed to evaluate the performance of the proposed algorithms and the results show that our proposed algorithms can effectively reduce the resource waste.

Predefined Exponential Basis Set for Half-Bounded Multi Domain Spectral Method

A non-orthogonal predefined exponential basis set is used to handle half-bounded domains in multi domain spectral method (MDSM). This approach works extremely well for real-valued semi-infinite differential problems. It spans simultaneously wide range of exponential decay rates with multi scaling and does not suffer from zero crossing. These two conditions are necessary for many physical problems. For comparison, the method is used to solve different problems and compared with analytical and published results. The comparison exhibits the strengths and accuracy of the presented basis set.

1310 nm Source Spectral-Domain Optical Coherence Tomography for Chinese Pigment and Jadeite Research

Optical Coherence Tomography (OCT) technique is a nondestructive optical detection technology based on low-coherence interferometer and it has become an attractive cultural heritage research method. A 1310 nm source spectral-domain optical coherence tomography (SD-OCT) system based on optical fiber Michelson interferometer and optical spectrum analyzer is proposed and demonstrated for Chinese cultural heritage research. The cross-section OCT images of Chinese pigment samples and jadeite samples can provide a lot of valuable microstructure information for the Chinese cultural heritage research and identification works.

Time-Spectral Solution of Initial-Value Problems—Subdomain Approach

Temporal and spatial subdomain techniques are proposed for a time-spectral method for solution of initial-value problems. The spectral method, called the generalised weighted residual method (GWRM), is a generalisation of weighted residual methods to the time and parameter domains [1]. A semi-analytical Chebyshev polynomial ansatz is employed, and the problem reduces to determine the coefficients of the ansatz from linear or nonlinear algebraic systems of equations. In order to avoid large memory storage and computational cost, it is preferable to subdivide the temporal and spatial domains into subdomains. Methods and examples of this article demonstrate how this can be achieved.

A Novel High Spectral Efficiency Waveform Coding-OVFDM

Based on the Overlapped Multiplexing Principle[12],a frequency domain OVFDM(Overlapped Frequency Domain Multiplexing) Coding is proposed.By the data weighted shift overlapped version of any band-limited Multiplexing Transfer Function H(f) the coding gain and spectral efficiency are both achieved.The heavier the overlap of the data weighted Multiplexing Transfer Function H(f),the higher the coding gain and spectral efficiency as well as the closer the output to the optimum complex Gaussian distribution.The bit error probability performance is estimated.The time domain OVTDM(Overlapped Time Domain Multiplexing) Coding,the dual of OVFDM in time domain is incidentally proposed as well.Both theoretical analysis and testified simulations show that OVFDM(OVTDM) is suitable for high spectral efficiency application and its spectral efficiency is only roughly linear to SNR rather than the well-known logarithm to SNR.