AIM:To determine the utility of the RS-1 spectral domain optical coherence tomography(SD-OCT),which incorporates an“OCT Analysis Correction Parameter”for approximating axial length,in comparison with measurements ob...AIM:To determine the utility of the RS-1 spectral domain optical coherence tomography(SD-OCT),which incorporates an“OCT Analysis Correction Parameter”for approximating axial length,in comparison with measurements obtained from the OA-2000.METHODS:Twenty-five right eyes of healthy individuals were included.Two horizontal line scans were conducted using the RS-1,and OCT Analysis Correction Parameters were recorded.Axial length was measured twice per eye using the OA-2000.Correlation between devices was assessed using Pearson correlation coefficient,coefficient of repeatability(CR%),and Bland-Altman analysis.RESULTS:High correlation was found between axial length measurements from RS-1 and OA-2000(r=0.986,P<0.0001).The coefficient of repeatability was 1.56%for RS-1 and 0.115%for OA-2000.Mean axial length was 25.12±1.38 mm for RS-1 and 24.90±1.54 mm for OA-2000,with RS-1 showing a statistically significant larger value(paired t-test,P=0.0009).CONCLUSION:The axial length measurements of RS-1 demonstrate a strong positive correlation with those from the OA-2000.This indicates that it could potentially be used to forecast scan ranges and choose suitable databases according to axial length categories.展开更多
AIM:To evaluate the choroidopathy in patients with systemic lupus erythematosus(SLE)using enhanced depth imaging spectral domain optical coherence tomography(EDI SD-OCT)and optical coherence tomography angiography(OCT...AIM:To evaluate the choroidopathy in patients with systemic lupus erythematosus(SLE)using enhanced depth imaging spectral domain optical coherence tomography(EDI SD-OCT)and optical coherence tomography angiography(OCTA).METHODS:A total of 74 patients with SLE and 40 healthy volunteers were included in this cross-sectional study.SLE patients were further divided into three subgroups based on clinical and blood biochemistry findings.Ocular parameters obtained on ophthalmologic examination and optical imaging(EDI SD-OCT and OCTA)included the best corrected distance visual acuity(logMAR CDVA),subfoveal choroidal thickness(SCT),choroidal vascularity index(CVI)and vessel density(VD)of superficial capillary plexus(SCP)and deep capillary plexus(DCP).RESULTS:SLE patients had significantly lower values for CVI and VD of DCP(DVD)than control subjects.Amongst SLE patients,gender and chloroquine dose were found to be independent determinants of CVI while age predicted SCT.Steroid dose was a significant predictor for foveal VD of SCP(SVD),chloroquine dose for parafoveal SVD,gender for total DVD,and gender and steroid dose for perifoveal DVD.No correlation of logMAR CDVA and SCT was noted between SLE patients and control subjects.No correlation of SCT was noted with disease duration,Systemic Lupus Erythematosus Disease Activity Index(SLEDAI)score,hydroxychloroquine(HCQ)dose or steroid dose.No correlation of CVI was noted with patient age,disease duration,SLEDAI score,HCQ dose or steroid dose.No significant difference was noted between SLE subgroups in terms of any of the ocular parameters studied.CONCLUSION:The findings reveal the presence of ocular findings suggestive of early onset choroidopathy on EDI SD-OCT and OCTA in SLE patients,in the absence of ocular manifestations or active disease.展开更多
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 an...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.展开更多
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.
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 di...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.展开更多
Taking partially coherent cosh-Gaussian （ChG） beams as an example of more general partially coherent beams, we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is sh...Taking partially coherent cosh-Gaussian （ChG） beams as an example of more general partially coherent beams, we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is shown that, unlike Gaussian Schell-model （GSM） beams, in the strict sense there do not exist two partially coherent ChG beams which can generate far fields with the same spectral degree of coherence. However, under certain conditions it is possible to find two partially coherent ChG beams with the same spectral degree of coherence in the far field.展开更多
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...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.展开更多
AIM:To measure the central choroidal thickness(ChT)in children and adolescents with anxiety disorders.METHODS:Totally 41 anxiety patients(8-16 y)and 35 healthy controls(age-matched)were evaluated.Complete ophthalmic e...AIM:To measure the central choroidal thickness(ChT)in children and adolescents with anxiety disorders.METHODS:Totally 41 anxiety patients(8-16 y)and 35 healthy controls(age-matched)were evaluated.Complete ophthalmic examination was performed.Inclusion criteria were best corrected visual acuity≥20/20,normal intraocular pressure(IOP;10-21 mm Hg),and no systemic or ocular diseases according to history.The diagnosis of psychiatric disorders was determined using Schedule for Affective Disorders and Schizophrenia for School Aged Children Present-Lifetime Version(K-SADS-PL).Enhanced depth imaging optical coherence tomography(EDI-OCT)was used to measure the central ChT.RESULTS:The mean age was 12.18±3.24 y in the patient group and 12.86±3.15 y in the control group.Age and gender distribution of the two groups was similar.Central ChT mean value was 353.26±31.9μm in anxiety patients while 318.75±60.9μm in the control group.Mean central ChT was statistically significantly higher in the children and adolescents with anxiety disorders than healthy controls(P=0.002).CONCLUSION:The children and adolescents with anxiety disorders have significantly thicker central ChT than controls.In the larger sample,longitudinal studies will contribute to the use of choroidal differences as a clinical marker for monitoring anxiety disorders.展开更多
In this study, we explore the far-zero behaviors of a scattered partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam irradiating on a deterministic medium. The analytical formula...In this study, we explore the far-zero behaviors of a scattered partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam irradiating on a deterministic medium. The analytical formula for the cross-spectral density matrix elements of this beam in the spherical coordinate system is derived. Within the framework of the first-order Born approximation, the effects of the scattering angle θ, the source parameters (i.e., the pulse duration T0 and the temporal coherence length Tcxx), and the scatterer parameter (i.e., the effective width of the medium σR) on the spectral density, the spectral shift, the spectral degree of polarization, and the degree of spectral coherence of the scattered source in the far-zero field are studied numerically and comparatively. Our work improves the scattering theory of stochastic electromagnetic beams and it may be useful for the applications involving the interaction between incident light waves and scattering media.展开更多
AIM:To quantify and compare longitudinal thickness changes of the ganglion cell complex(GCC)and the choroid in patients with different patterns of age-related macular degeneration(AMD)progression.METHODS:Retrospective...AIM:To quantify and compare longitudinal thickness changes of the ganglion cell complex(GCC)and the choroid in patients with different patterns of age-related macular degeneration(AMD)progression.METHODS:Retrospective cohort analysis of anonymized data from participants aged 50y or more and diagnosed with early/intermediate AMD in at least one eye(with no evidence of advanced AMD).A total of 64 participants were included from the Instituto de Retina de Lisboa(IRL)study(IPL/2022/MetAllAMD_ESTeSL)and divided into 4 groups according to the Rotterdam classification for AMD.Spectral domain optical coherence tomography(SD-OCT)was used to assess and quantify GCC and choroid thickness at two time points(first visit vs last visit)with a minimum interval of 3y.RESULTS:In the GCC inner ring,a thinner thickness(P=0.001)was observed in the atrophic AMD group(51.3±21.4μm)compared to the early AMD(84.3±11.5μm),intermediate AMD(77.6±16.1μm)and neovascular AMD(88.9±16.3μm)groups.Choroidal thickness quantification showed a generalized reduction in the central circle(P=0.002)and inner ring(P=0.001).Slight reductions in retinal thickness were more accentuated in the inner ring in the atrophic AMD(-13%;P<0.01).CONCLUSION:The variation of the analyzed structures could be an indicator of risk of progression with neurodegenerative(GCC)or vascular(choroid)pattern in the intermediate and atrophic AMD.The quantification of both structures can provide important information about the risk of disease progression in the early and intermediate stages but also for the evolution pattern into late stages(atrophic or neovascular).展开更多
AIM:To elucidate the manifestations and associated complications observed in patients with intraocular silicone oil(SO)emulsification through multiple imaging modalities.METHODS:This single-center,observational,retros...AIM:To elucidate the manifestations and associated complications observed in patients with intraocular silicone oil(SO)emulsification through multiple imaging modalities.METHODS:This single-center,observational,retrospective study included 116 patients who underwent pars plana vitrectomy(PPV)with SO injection for retinal detachment(RD),followed by subsequent SO removal at the Second Hospital of Hebei Medical University from January 2013 to January 2023.Comprehensive records of ophthalmic examinations utilizing multiple imaging techniques were maintained.RESULTS:The study comprised 56 females and 60 males,with a mean age of 52.75±13.6y.The mean follow-up duration for SO tamponade was 9.04±11.33mo(range:1-84mo).Among the participants,59 patients were diagnosed with SO emulsification,while 57 patients were in the SO unemulsified group.Patients with SO emulsification had a significantly prolonged SO tamponade duration(P<0.01).Multiple imaging techniques revealed notable signs of SO emulsification and its complications,such as 4 cases(3.4%)with posterior corneal SO-like keratic precipitates(KP)observed by anterior segment photography,23 cases(19.8%)exhibiting spherical high-reflection signals in the inter-retina,retinal pigment epithelium,or choroid detected by Spectralis spectral domain optical coherence tomography(SD-OCT),4 cases(3.4%)showing slow movement of emulsified SO droplets within retinal vessels during fluorescein angiography(FFA),plain and enhanced head magnetic resonance imaging(MRI)images of these four patients did not detect emulsified SO in the lateral ventricles,suprasellar cistern,subarachnoid space,third ventricle,fourth ventricle,or other intracranial locations.CONCLUSION:Intraocular emulsified SO can lead to damage in both anterior and posterior segment tissues,encompassing corneal degeneration,cataracts,glaucoma,retinal and choroid inflammation.Objective multiple imaging techniques such as anterior segment photography,SD-OCT,FFA,and MRI offer comprehensive evaluation and diagnosis of SO emulsification and its associated complications.展开更多
For the purpose of investigating the turbulent and spatial coherent characteristics of strong wind during typhoon landing period,two 3-dimensional ultrasonic anemometer stations were set up 30 m horizontally apart on ...For the purpose of investigating the turbulent and spatial coherent characteristics of strong wind during typhoon landing period,two 3-dimensional ultrasonic anemometer stations were set up 30 m horizontally apart on the Macao Friendship Bridge to caputure the turbulent wind velocities of Typhoon Nuri.Based on the reliable and representative field measured data,the mean wind speed and direction,turbulence intensity,turbulence integral scale,turbulence power spectra,spatial correlation coefficient and coherence function were statistically evaluated.The field measurement analysis have presented the following results:1)Two anemometer stations provided consistent results.The mean wind speed variation in time domain presented typical M-shape curves.The strong wind(10-minute mean wind speed higher than 8th grade in Beaufort wind scale)direction changed in a big range up to 122-degrees-angle,indicating the field measurements scoped over the typhoon landing period.2)The ratio of the longitudinal,lateral and vertical turbulence intensities of the strong wind in the typhoon eye wall region was 1:0.96:0.36.Compared with the code defined ratio 1:0.88:0.5,the lateral component was larger and the vertical component was smaller.3)The value of integral scale increased when the eye wall of Typhoon Nuri passed over the field measurement site.Before the center of Typhoon Nuri arrived,the integral scale of the strong typhoon wind was about twice compared with that for the non-typhoon wind.4)The spatial correlation of the turbulent wind,coherence function curve and the decay factor had significant differences at different times during the typhoon process.In the eye wall of the typhoon,the horizontal spatial correlation was relatively strong and horizontally spatial correlation spectrum decayed slower with frequency increase.The minimum regressed coefficient C in coherence function model was 4.67,which is lower than the code defined low limit.The maximum decay factor was 27.75 which is larger than the code defined upper bound.The strong wind characteristic parameters of Typhoon Nuri mentioned above partly represented the turbulent and spatial coherent characteristic during strong typhoon wind period.展开更多
The influence of optical nonlinearity on combining efficiency in ultrashort pulse fiber laser coherent combining system is investigated theoretically and experimentally.In the theoretical work,a new theoretical algori...The influence of optical nonlinearity on combining efficiency in ultrashort pulse fiber laser coherent combining system is investigated theoretically and experimentally.In the theoretical work,a new theoretical algorithm is presented for the coherent combining efficiency,which can be used to quantify the spectral coherence decay induced by optical nonlinearity imbalance between the sub-beams.The spectral information of the sub-beam is obtained by numerically solving the nonlinear Schrödinger equation(NLSE)in this algorithm to ensure an accurate prediction.In the experimental work,the coherent combining of two all-fiber picosecond lasers is achieved,and the influence of imbalanced optical nonlinearity on the combining efficiency is studied,which agrees with the theoretical prediction.This paper reveals the physical mechanism for the influence of optical nonlinearity on the combining efficiency,which is valuable for the coherent combining of ultrashort pulse fiber laser beams.展开更多
AIM:To compare the RTVue spectral optical coherence tomography(SD-OCT),Sirius Scheimpflug-Placido topographer,Lenstar optical low coherence reflectometry(OLCR)and ultrasound pachymetry(USP)devices in terms of their ag...AIM:To compare the RTVue spectral optical coherence tomography(SD-OCT),Sirius Scheimpflug-Placido topographer,Lenstar optical low coherence reflectometry(OLCR)and ultrasound pachymetry(USP)devices in terms of their agreement and repeatability of measuring central corneal thickness(CCT).METHODS:In this prospective study,50 eyes of 50patients were included.Three repeated measures were obtained using SD-OCT,Scheimpflug-Placido topographer and USP and five measurements were determined with the OLCR.Bland-Altman plots were used to assess agreement among the instruments,and 95%limits of agreement(LoA)for each comparison were calculated.Intra-examiner repeatability was assessed using intraclass correlation coefficients(ICCs).RESULTS:The mean CCT by SD-OCT,ScheimpflugPlacido topographer,OLCR,and USP were 525.90±34.08μm,525.92±34.10μm,530.30±35.62μm,and543.50±37.11μm respectively.All 4 modalities of CCT measurements correlated closely with each other,with Pearson correlation coefficients ranging from 0.977 to0.995.The mean differences(and upper/lower LoA)for CCT measurements were-0.05±6.77μm(13.3/-13.3)between SD-OCT and Scheimpflug-Placido topographer,4.38±3.79μm(11.8/-3.1)between OLCR and SD-OCT,4.38±6.03μm(16.2/-7.5)between OLCR and ScheimpflugPlacido topographer,13.20±6.46μm(25.9/0.5)between USP and OLCR,17.59±6.76μm(30.8/4.3)between USP and SD-OCT,and 17.58±8.13μm(33.5/1.6)between USP and Scheimpflug-Placido topographer.Intra-examiner repeatability was excellent for all devices with ICCs】0.98.CONCLUSION:For most practical purposes,CCT measurements with the RTVue,Sirius and Lenstar can be used interchangeably.Although highly correlated,CCTmeasurement differences between USP and these 3optical instruments can be significant depending on the clinical situation.展开更多
BACKGROUND Anterior ischemic optic neuropathy(AION)is a group of ophthalmic diseases in which the optic nerve is injured causing blindness.However,the pathogenesis,clinical manifestations,and clinical treatments of AI...BACKGROUND Anterior ischemic optic neuropathy(AION)is a group of ophthalmic diseases in which the optic nerve is injured causing blindness.However,the pathogenesis,clinical manifestations,and clinical treatments of AION are yet elusive.Only a few related experimental or clinical reports are available on the disease.In this study,spectral domain optical coherence tomography(SD-OCT)was used to examine the morphology of thickness swelling and atrophic changes of macular ganglion cell complex(mGCC)in the different stages of AION that were then compared with the visual fields.Thus,the clinical value of mGCC examination was alleged to be similar to that of the visual field.AIM To explore the mGCC injury at different stages in AION and the clinical significance.METHODS Cases with AION were analyzed in a retrospective study.SD-OCT was used to analyze the correlation between mGCC and peripapillary retinal nerve fiber layer thicknesses at different stages of AION and the changes in the corresponding stages of visual fields.RESULTS A total of 21 cases(28 eyes)presented AION.The onset time of AION was defined as early stage(within 3 wk of onset),middle stage(from 3 wk to 2 mo),and late stage(disease span>2 mo).In the early stage,the mGCC thickness of SD-OCT was within the normal high limit,and the perioptic nerve fibers thickness was more than the normal.The changes in the visual field in early stage were not consistent with the swelling changes in mGCC and peri-disc nerve fibers.In addition,atrophy and thinning appeared in mGCC,and the perioptic nerve fibers were swollen.However,the thickness was lower in the middle period than that in the early stage.The change in visual field was consistent with that of mGCC in this period.In the late stage,mGCC shrank and thinned,and the thickness of the nerve fibers around the optic disc in the corresponding region shrank and thinned.CONCLUSION The changes in mGCC thickness in patients with AION showed early,middle,and late stages of development by SD-OCT.Although the early stage visual field changes of AION were not consistent with the swelling changes of mGCC,the horizontal delimitation or annular atrophy of mGCC was consistent with that in the middle and late stage of the disease.The atrophy of peripheral nerve fibers was later than that of the mGCC atrophy.展开更多
AIM: To evaluate the patterns of macular ganglion cell-inner plexiform layer(GCIPL) loss in normal tension glaucoma(NTG) and primary open angle glaucoma(POAG) in a detailed, disease severity-matched way;and to assess ...AIM: To evaluate the patterns of macular ganglion cell-inner plexiform layer(GCIPL) loss in normal tension glaucoma(NTG) and primary open angle glaucoma(POAG) in a detailed, disease severity-matched way;and to assess the diagnostic capabilities of GCIPL thickness parameters in discriminating NTG or POAG from normal subjects.METHODS: A total of 157 eyes of 157 subjects, including 57 normal eyes, 51 eyes with POAG and 49 eyes with NTG were enrolled and strictly matched in age, refraction, and disease severity between POAG and NTG groups. The average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL thickness, and the average, superior, temporal, inferior, and nasal retinal nerve fiber layer(RNFL) thickness were obtained by Cirrus optical coherence tomography(OCT). The diagnostic capabilities of OCT parameters were assessed by area under receiver operating characteristic(AUROC) curves. RESULTS: Among all the OCT thickness parameters, no statistical significant difference between NTG group and POAG group was found(all P>0.05). In discriminating NTG or POAG from normal subjects, the average and inferior RNFL thickness, and the minimum GCIPL thickness had better diagnostic capabilities. There was no significant difference in AUROC curve between the best GCIPL thickness parameter(minimum GCIPL) and the best RNFL thickness parameter in discriminating NTG(inferior RNFL;P=0.076) and indiscriminating POAG(average RNFL;P=0.913) from normal eyes.CONCLUSION: Localized GCIPL loss, especially in the inferior and inferotemporal sectors, is more common in NTG than in POAG. Among all the GCIPL thickness parameters, the minimum GCIPL thickness has the best diagnostic performance in differentiating NTG or POAG from normal subjects, which is comparable to that of the average and inferior RNFL thickness.展开更多
We introduce a method based on Gaussian mixture model(GMM)clustering and level-set to automatically detect intraretina fluid on diabetic retinopathy(DR)from spectral domain optical coherence tomography(SD-OCT)images i...We introduce a method based on Gaussian mixture model(GMM)clustering and level-set to automatically detect intraretina fluid on diabetic retinopathy(DR)from spectral domain optical coherence tomography(SD-OCT)images in this paper.First,each B-scan is segmented using GMM clustering.The original chustering results are refined using location and thickness infor-mation.Then,the spatial information among every consecutive five B-scans is used to search potential fluid.Finally,the improved level-set method is used to obtain the accurate boundaries.The high sensitivity and accuracy demonstrated here show its potential for detection of fluid.展开更多
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 op...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.展开更多
AIM: To evaluate temporal retinal thinning changes in retinal layers using spectral-domain optical coherence tomography(SD-OCT) in pediatric X-linked Alport syndrome(XLAS) patients.METHODS: A retrospective case-contro...AIM: To evaluate temporal retinal thinning changes in retinal layers using spectral-domain optical coherence tomography(SD-OCT) in pediatric X-linked Alport syndrome(XLAS) patients.METHODS: A retrospective case-control study. SDOCT scans of pediatric patients diagnosed with XLAS and age-and sex-matched healthy control participants were reviewed. Automated segmentation of SD-OCT scans was induced to analyze the retinal thickness(RT) of different layers. The temporal thinning index(TTI) was calculated for each layer and compared between the patients and the control group.RESULTS: Forty-three pediatric XLAS patients and 60 healthy controls were included. Temporal retinal thinning was present in 33 patients(76.74%), while 28 patients(65.11%) had severe pathological temporal retinal thinning and 5 patients(11.63%) had moderate thinning. The temporal inner sector RT(P<0.0001), the temporal outer sector RT(P<0.0001), and the nasal outer sector RT(P=0.0211) were significantly thinner in the XLAS male patients. The TTI of the total retina was significantly higher in the XLAS group than in the control group(P<0.0001). The TTI of the inner retina layers(P<0.0001), ganglion cell layer(P<0.0001), inner plexiform layer(P<0.0001), inner nuclear layer(P<0.0001), and outer nuclear layer(P<0.0001) were significantly higher in the XLAS group. The central RT of the XLAS group was significantly thinner than that of the control group(P<0.0001).CONCLUSION: Temporal retinal thinning appears early in XLAS patients, especially in male patients. The thinningis mainly caused by structural abnormalities of the inner retina. This suggests that temporal retinal thinning could be helpful for the early diagnosis and follow-up of XLAS with noninvasive SD-OCT examination.展开更多
AIM:To evaluate the effect of vitamin B12 deficiency anemia(BDA)on peripapillary retinal nerve fiber layer thickness(RNFLT)using spectral domain optical coherence tomography(SD-OCT),and to determine any correlation ar...AIM:To evaluate the effect of vitamin B12 deficiency anemia(BDA)on peripapillary retinal nerve fiber layer thickness(RNFLT)using spectral domain optical coherence tomography(SD-OCT),and to determine any correlation arising thereof.METHODS:In this cross-sectional observational study,99 eyes of 50 BDA patients of age 18-65 y were compared with 100 eyes of 50 healthy control subjects.All subjects underwent comprehensive clinical,ophthalmic,and hematological evaluation,followed by peripapillary RNFLT assessment using SD-OCT.RESULTS:The mean total,inferior,nasal,and temporal RNFLT were significantly lower in BDA group as compared to control group(P<0.05).The mean total,inferior and nasal RNFLT correlated significantly(P<0.05)with serum Hb%,B12 and mean corpuscular volume(MCV)level(r=0.310,0.435,-0.386 for total;r=0.932,0.481,-0.513 for inferior;r=0.344,0.254,-0.233 for nasal;respectively),while temporal and superior RNFLT quadrant did not show any correlation with any of the hematological parameters(r=0.144,0.167,-0.096;r=0.111,0.070,-0.099;respectively).The mean total RNFLT showed progressive thinning at par with the progression of anemia,except in very severe BDA,where an inverse relationship was documented.CONCLUSION:The mean total,inferior,nasal,and temporal peripapillary RNFLT was significantly thinner in BDA patients.Peripapillary RNFLT thinning seemed to proceed at par with the progression of severity of anemia,except in very sever grade.Early assessment of peripapillary RNFLT may be crucial in BDA patients to prevent potential blinding sequelae.Peripapillary RNFLT thinning in BDA patients should be considered in the differential diagnosis of other non-glaucomatous optic neuropathies,as well.展开更多
文摘AIM:To determine the utility of the RS-1 spectral domain optical coherence tomography(SD-OCT),which incorporates an“OCT Analysis Correction Parameter”for approximating axial length,in comparison with measurements obtained from the OA-2000.METHODS:Twenty-five right eyes of healthy individuals were included.Two horizontal line scans were conducted using the RS-1,and OCT Analysis Correction Parameters were recorded.Axial length was measured twice per eye using the OA-2000.Correlation between devices was assessed using Pearson correlation coefficient,coefficient of repeatability(CR%),and Bland-Altman analysis.RESULTS:High correlation was found between axial length measurements from RS-1 and OA-2000(r=0.986,P<0.0001).The coefficient of repeatability was 1.56%for RS-1 and 0.115%for OA-2000.Mean axial length was 25.12±1.38 mm for RS-1 and 24.90±1.54 mm for OA-2000,with RS-1 showing a statistically significant larger value(paired t-test,P=0.0009).CONCLUSION:The axial length measurements of RS-1 demonstrate a strong positive correlation with those from the OA-2000.This indicates that it could potentially be used to forecast scan ranges and choose suitable databases according to axial length categories.
文摘AIM:To evaluate the choroidopathy in patients with systemic lupus erythematosus(SLE)using enhanced depth imaging spectral domain optical coherence tomography(EDI SD-OCT)and optical coherence tomography angiography(OCTA).METHODS:A total of 74 patients with SLE and 40 healthy volunteers were included in this cross-sectional study.SLE patients were further divided into three subgroups based on clinical and blood biochemistry findings.Ocular parameters obtained on ophthalmologic examination and optical imaging(EDI SD-OCT and OCTA)included the best corrected distance visual acuity(logMAR CDVA),subfoveal choroidal thickness(SCT),choroidal vascularity index(CVI)and vessel density(VD)of superficial capillary plexus(SCP)and deep capillary plexus(DCP).RESULTS:SLE patients had significantly lower values for CVI and VD of DCP(DVD)than control subjects.Amongst SLE patients,gender and chloroquine dose were found to be independent determinants of CVI while age predicted SCT.Steroid dose was a significant predictor for foveal VD of SCP(SVD),chloroquine dose for parafoveal SVD,gender for total DVD,and gender and steroid dose for perifoveal DVD.No correlation of logMAR CDVA and SCT was noted between SLE patients and control subjects.No correlation of SCT was noted with disease duration,Systemic Lupus Erythematosus Disease Activity Index(SLEDAI)score,hydroxychloroquine(HCQ)dose or steroid dose.No correlation of CVI was noted with patient age,disease duration,SLEDAI score,HCQ dose or steroid dose.No significant difference was noted between SLE subgroups in terms of any of the ocular parameters studied.CONCLUSION:The findings reveal the presence of ocular findings suggestive of early onset choroidopathy on EDI SD-OCT and OCTA in SLE patients,in the absence of ocular manifestations or active disease.
文摘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.
基金Supported by the Korean Ministry of Environment through"The Environmental Health Action Program",Korea(No.2012001350010)Korea University(No.K1400629)
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China (Grant Nos 10574097 and 10874125)
文摘Taking partially coherent cosh-Gaussian （ChG） beams as an example of more general partially coherent beams, we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is shown that, unlike Gaussian Schell-model （GSM） beams, in the strict sense there do not exist two partially coherent ChG beams which can generate far fields with the same spectral degree of coherence. However, under certain conditions it is possible to find two partially coherent ChG beams with the same spectral degree of coherence in the far field.
文摘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.
文摘AIM:To measure the central choroidal thickness(ChT)in children and adolescents with anxiety disorders.METHODS:Totally 41 anxiety patients(8-16 y)and 35 healthy controls(age-matched)were evaluated.Complete ophthalmic examination was performed.Inclusion criteria were best corrected visual acuity≥20/20,normal intraocular pressure(IOP;10-21 mm Hg),and no systemic or ocular diseases according to history.The diagnosis of psychiatric disorders was determined using Schedule for Affective Disorders and Schizophrenia for School Aged Children Present-Lifetime Version(K-SADS-PL).Enhanced depth imaging optical coherence tomography(EDI-OCT)was used to measure the central ChT.RESULTS:The mean age was 12.18±3.24 y in the patient group and 12.86±3.15 y in the control group.Age and gender distribution of the two groups was similar.Central ChT mean value was 353.26±31.9μm in anxiety patients while 318.75±60.9μm in the control group.Mean central ChT was statistically significantly higher in the children and adolescents with anxiety disorders than healthy controls(P=0.002).CONCLUSION:The children and adolescents with anxiety disorders have significantly thicker central ChT than controls.In the larger sample,longitudinal studies will contribute to the use of choroidal differences as a clinical marker for monitoring anxiety disorders.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11504286)the Natural Science Basic Research Program of Shaanxi Province, China (Grant No. 2019JM-470)+1 种基金the Fund from the International Technology Collaborative Center for Advanced Optical Manufacturing and Optoelectronic Measurementthe Science Fund from the Shaanxi Provincial Key Laboratory of Photoelectric Measurement and Instrument Technology.
文摘In this study, we explore the far-zero behaviors of a scattered partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam irradiating on a deterministic medium. The analytical formula for the cross-spectral density matrix elements of this beam in the spherical coordinate system is derived. Within the framework of the first-order Born approximation, the effects of the scattering angle θ, the source parameters (i.e., the pulse duration T0 and the temporal coherence length Tcxx), and the scatterer parameter (i.e., the effective width of the medium σR) on the spectral density, the spectral shift, the spectral degree of polarization, and the degree of spectral coherence of the scattered source in the far-zero field are studied numerically and comparatively. Our work improves the scattering theory of stochastic electromagnetic beams and it may be useful for the applications involving the interaction between incident light waves and scattering media.
基金Supported by FCT/MCTES UIDB/05608/2020(https://doi.org/10.54499/UIDB/05608/2020)UIDP/05608/2020(https://doi.org/10.54499/UIDP/05608/2020)+1 种基金IDI&CA grant IPL/2022/MetAllAMD_ESTeSL by H&TRC-Health&Technology Research Center,ESTeSL-Escola Superior de Tecnologia da Saúde,Instituto Politécnico de Lisboaby Retina Institute of Lisbon(IRL).
文摘AIM:To quantify and compare longitudinal thickness changes of the ganglion cell complex(GCC)and the choroid in patients with different patterns of age-related macular degeneration(AMD)progression.METHODS:Retrospective cohort analysis of anonymized data from participants aged 50y or more and diagnosed with early/intermediate AMD in at least one eye(with no evidence of advanced AMD).A total of 64 participants were included from the Instituto de Retina de Lisboa(IRL)study(IPL/2022/MetAllAMD_ESTeSL)and divided into 4 groups according to the Rotterdam classification for AMD.Spectral domain optical coherence tomography(SD-OCT)was used to assess and quantify GCC and choroid thickness at two time points(first visit vs last visit)with a minimum interval of 3y.RESULTS:In the GCC inner ring,a thinner thickness(P=0.001)was observed in the atrophic AMD group(51.3±21.4μm)compared to the early AMD(84.3±11.5μm),intermediate AMD(77.6±16.1μm)and neovascular AMD(88.9±16.3μm)groups.Choroidal thickness quantification showed a generalized reduction in the central circle(P=0.002)and inner ring(P=0.001).Slight reductions in retinal thickness were more accentuated in the inner ring in the atrophic AMD(-13%;P<0.01).CONCLUSION:The variation of the analyzed structures could be an indicator of risk of progression with neurodegenerative(GCC)or vascular(choroid)pattern in the intermediate and atrophic AMD.The quantification of both structures can provide important information about the risk of disease progression in the early and intermediate stages but also for the evolution pattern into late stages(atrophic or neovascular).
基金Supported by the Natural Science Foundation of Hebei Province(No.H2023206907).
文摘AIM:To elucidate the manifestations and associated complications observed in patients with intraocular silicone oil(SO)emulsification through multiple imaging modalities.METHODS:This single-center,observational,retrospective study included 116 patients who underwent pars plana vitrectomy(PPV)with SO injection for retinal detachment(RD),followed by subsequent SO removal at the Second Hospital of Hebei Medical University from January 2013 to January 2023.Comprehensive records of ophthalmic examinations utilizing multiple imaging techniques were maintained.RESULTS:The study comprised 56 females and 60 males,with a mean age of 52.75±13.6y.The mean follow-up duration for SO tamponade was 9.04±11.33mo(range:1-84mo).Among the participants,59 patients were diagnosed with SO emulsification,while 57 patients were in the SO unemulsified group.Patients with SO emulsification had a significantly prolonged SO tamponade duration(P<0.01).Multiple imaging techniques revealed notable signs of SO emulsification and its complications,such as 4 cases(3.4%)with posterior corneal SO-like keratic precipitates(KP)observed by anterior segment photography,23 cases(19.8%)exhibiting spherical high-reflection signals in the inter-retina,retinal pigment epithelium,or choroid detected by Spectralis spectral domain optical coherence tomography(SD-OCT),4 cases(3.4%)showing slow movement of emulsified SO droplets within retinal vessels during fluorescein angiography(FFA),plain and enhanced head magnetic resonance imaging(MRI)images of these four patients did not detect emulsified SO in the lateral ventricles,suprasellar cistern,subarachnoid space,third ventricle,fourth ventricle,or other intracranial locations.CONCLUSION:Intraocular emulsified SO can lead to damage in both anterior and posterior segment tissues,encompassing corneal degeneration,cataracts,glaucoma,retinal and choroid inflammation.Objective multiple imaging techniques such as anterior segment photography,SD-OCT,FFA,and MRI offer comprehensive evaluation and diagnosis of SO emulsification and its associated complications.
基金supported by the National Natural Science Foundation of China(Grant Nos.90715031,40775071)
文摘For the purpose of investigating the turbulent and spatial coherent characteristics of strong wind during typhoon landing period,two 3-dimensional ultrasonic anemometer stations were set up 30 m horizontally apart on the Macao Friendship Bridge to caputure the turbulent wind velocities of Typhoon Nuri.Based on the reliable and representative field measured data,the mean wind speed and direction,turbulence intensity,turbulence integral scale,turbulence power spectra,spatial correlation coefficient and coherence function were statistically evaluated.The field measurement analysis have presented the following results:1)Two anemometer stations provided consistent results.The mean wind speed variation in time domain presented typical M-shape curves.The strong wind(10-minute mean wind speed higher than 8th grade in Beaufort wind scale)direction changed in a big range up to 122-degrees-angle,indicating the field measurements scoped over the typhoon landing period.2)The ratio of the longitudinal,lateral and vertical turbulence intensities of the strong wind in the typhoon eye wall region was 1:0.96:0.36.Compared with the code defined ratio 1:0.88:0.5,the lateral component was larger and the vertical component was smaller.3)The value of integral scale increased when the eye wall of Typhoon Nuri passed over the field measurement site.Before the center of Typhoon Nuri arrived,the integral scale of the strong typhoon wind was about twice compared with that for the non-typhoon wind.4)The spatial correlation of the turbulent wind,coherence function curve and the decay factor had significant differences at different times during the typhoon process.In the eye wall of the typhoon,the horizontal spatial correlation was relatively strong and horizontally spatial correlation spectrum decayed slower with frequency increase.The minimum regressed coefficient C in coherence function model was 4.67,which is lower than the code defined low limit.The maximum decay factor was 27.75 which is larger than the code defined upper bound.The strong wind characteristic parameters of Typhoon Nuri mentioned above partly represented the turbulent and spatial coherent characteristic during strong typhoon wind period.
基金upported by the Key Program of Beijing Municipal Natural Science Foundation,China(Grant No.KZ201910005006)the National Natural Science Foundation of China(Grant No.62005004)+1 种基金Natural Science Foundation of Beijing Municipality,China(Grant No.4204091)National Science Foundation for Post-doctor Scientists of China(Grant No.212423)。
文摘The influence of optical nonlinearity on combining efficiency in ultrashort pulse fiber laser coherent combining system is investigated theoretically and experimentally.In the theoretical work,a new theoretical algorithm is presented for the coherent combining efficiency,which can be used to quantify the spectral coherence decay induced by optical nonlinearity imbalance between the sub-beams.The spectral information of the sub-beam is obtained by numerically solving the nonlinear Schrödinger equation(NLSE)in this algorithm to ensure an accurate prediction.In the experimental work,the coherent combining of two all-fiber picosecond lasers is achieved,and the influence of imbalanced optical nonlinearity on the combining efficiency is studied,which agrees with the theoretical prediction.This paper reveals the physical mechanism for the influence of optical nonlinearity on the combining efficiency,which is valuable for the coherent combining of ultrashort pulse fiber laser beams.
文摘AIM:To compare the RTVue spectral optical coherence tomography(SD-OCT),Sirius Scheimpflug-Placido topographer,Lenstar optical low coherence reflectometry(OLCR)and ultrasound pachymetry(USP)devices in terms of their agreement and repeatability of measuring central corneal thickness(CCT).METHODS:In this prospective study,50 eyes of 50patients were included.Three repeated measures were obtained using SD-OCT,Scheimpflug-Placido topographer and USP and five measurements were determined with the OLCR.Bland-Altman plots were used to assess agreement among the instruments,and 95%limits of agreement(LoA)for each comparison were calculated.Intra-examiner repeatability was assessed using intraclass correlation coefficients(ICCs).RESULTS:The mean CCT by SD-OCT,ScheimpflugPlacido topographer,OLCR,and USP were 525.90±34.08μm,525.92±34.10μm,530.30±35.62μm,and543.50±37.11μm respectively.All 4 modalities of CCT measurements correlated closely with each other,with Pearson correlation coefficients ranging from 0.977 to0.995.The mean differences(and upper/lower LoA)for CCT measurements were-0.05±6.77μm(13.3/-13.3)between SD-OCT and Scheimpflug-Placido topographer,4.38±3.79μm(11.8/-3.1)between OLCR and SD-OCT,4.38±6.03μm(16.2/-7.5)between OLCR and ScheimpflugPlacido topographer,13.20±6.46μm(25.9/0.5)between USP and OLCR,17.59±6.76μm(30.8/4.3)between USP and SD-OCT,and 17.58±8.13μm(33.5/1.6)between USP and Scheimpflug-Placido topographer.Intra-examiner repeatability was excellent for all devices with ICCs】0.98.CONCLUSION:For most practical purposes,CCT measurements with the RTVue,Sirius and Lenstar can be used interchangeably.Although highly correlated,CCTmeasurement differences between USP and these 3optical instruments can be significant depending on the clinical situation.
文摘BACKGROUND Anterior ischemic optic neuropathy(AION)is a group of ophthalmic diseases in which the optic nerve is injured causing blindness.However,the pathogenesis,clinical manifestations,and clinical treatments of AION are yet elusive.Only a few related experimental or clinical reports are available on the disease.In this study,spectral domain optical coherence tomography(SD-OCT)was used to examine the morphology of thickness swelling and atrophic changes of macular ganglion cell complex(mGCC)in the different stages of AION that were then compared with the visual fields.Thus,the clinical value of mGCC examination was alleged to be similar to that of the visual field.AIM To explore the mGCC injury at different stages in AION and the clinical significance.METHODS Cases with AION were analyzed in a retrospective study.SD-OCT was used to analyze the correlation between mGCC and peripapillary retinal nerve fiber layer thicknesses at different stages of AION and the changes in the corresponding stages of visual fields.RESULTS A total of 21 cases(28 eyes)presented AION.The onset time of AION was defined as early stage(within 3 wk of onset),middle stage(from 3 wk to 2 mo),and late stage(disease span>2 mo).In the early stage,the mGCC thickness of SD-OCT was within the normal high limit,and the perioptic nerve fibers thickness was more than the normal.The changes in the visual field in early stage were not consistent with the swelling changes in mGCC and peri-disc nerve fibers.In addition,atrophy and thinning appeared in mGCC,and the perioptic nerve fibers were swollen.However,the thickness was lower in the middle period than that in the early stage.The change in visual field was consistent with that of mGCC in this period.In the late stage,mGCC shrank and thinned,and the thickness of the nerve fibers around the optic disc in the corresponding region shrank and thinned.CONCLUSION The changes in mGCC thickness in patients with AION showed early,middle,and late stages of development by SD-OCT.Although the early stage visual field changes of AION were not consistent with the swelling changes of mGCC,the horizontal delimitation or annular atrophy of mGCC was consistent with that in the middle and late stage of the disease.The atrophy of peripheral nerve fibers was later than that of the mGCC atrophy.
基金Supported by National Natural Science Foundation of China(No.81800879)Natural Science Foundation of Guangdong Province(No.2017A030310372)+2 种基金Fundamental Research Funds of the State Key Laboratory of Ophthalmology,China(No.2018KF04 No.2017QN05)Sun Yat-Sen University Clinical Research 5010 Program(No.2014016)
文摘AIM: To evaluate the patterns of macular ganglion cell-inner plexiform layer(GCIPL) loss in normal tension glaucoma(NTG) and primary open angle glaucoma(POAG) in a detailed, disease severity-matched way;and to assess the diagnostic capabilities of GCIPL thickness parameters in discriminating NTG or POAG from normal subjects.METHODS: A total of 157 eyes of 157 subjects, including 57 normal eyes, 51 eyes with POAG and 49 eyes with NTG were enrolled and strictly matched in age, refraction, and disease severity between POAG and NTG groups. The average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL thickness, and the average, superior, temporal, inferior, and nasal retinal nerve fiber layer(RNFL) thickness were obtained by Cirrus optical coherence tomography(OCT). The diagnostic capabilities of OCT parameters were assessed by area under receiver operating characteristic(AUROC) curves. RESULTS: Among all the OCT thickness parameters, no statistical significant difference between NTG group and POAG group was found(all P>0.05). In discriminating NTG or POAG from normal subjects, the average and inferior RNFL thickness, and the minimum GCIPL thickness had better diagnostic capabilities. There was no significant difference in AUROC curve between the best GCIPL thickness parameter(minimum GCIPL) and the best RNFL thickness parameter in discriminating NTG(inferior RNFL;P=0.076) and indiscriminating POAG(average RNFL;P=0.913) from normal eyes.CONCLUSION: Localized GCIPL loss, especially in the inferior and inferotemporal sectors, is more common in NTG than in POAG. Among all the GCIPL thickness parameters, the minimum GCIPL thickness has the best diagnostic performance in differentiating NTG or POAG from normal subjects, which is comparable to that of the average and inferior RNFL thickness.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.61701192,61471226 and 61671242)the Natural Science Foundation of Shandong Province,China(Youth Fund Project)under Grant No.ZR2017QF004+3 种基金Natural Science Foundation of Shandong Province(Grant Nos.JQ201516 and 2018GGXl 01018)the Taishan scholar project of Shandong Province(No.tsqn2016023)Fundamental Research Funds for the Central University(30920140111004)the China Postdoctoral Science Foundation(No.2017M612178).
文摘We introduce a method based on Gaussian mixture model(GMM)clustering and level-set to automatically detect intraretina fluid on diabetic retinopathy(DR)from spectral domain optical coherence tomography(SD-OCT)images in this paper.First,each B-scan is segmented using GMM clustering.The original chustering results are refined using location and thickness infor-mation.Then,the spatial information among every consecutive five B-scans is used to search potential fluid.Finally,the improved level-set method is used to obtain the accurate boundaries.The high sensitivity and accuracy demonstrated here show its potential for detection of fluid.
文摘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.
文摘AIM: To evaluate temporal retinal thinning changes in retinal layers using spectral-domain optical coherence tomography(SD-OCT) in pediatric X-linked Alport syndrome(XLAS) patients.METHODS: A retrospective case-control study. SDOCT scans of pediatric patients diagnosed with XLAS and age-and sex-matched healthy control participants were reviewed. Automated segmentation of SD-OCT scans was induced to analyze the retinal thickness(RT) of different layers. The temporal thinning index(TTI) was calculated for each layer and compared between the patients and the control group.RESULTS: Forty-three pediatric XLAS patients and 60 healthy controls were included. Temporal retinal thinning was present in 33 patients(76.74%), while 28 patients(65.11%) had severe pathological temporal retinal thinning and 5 patients(11.63%) had moderate thinning. The temporal inner sector RT(P<0.0001), the temporal outer sector RT(P<0.0001), and the nasal outer sector RT(P=0.0211) were significantly thinner in the XLAS male patients. The TTI of the total retina was significantly higher in the XLAS group than in the control group(P<0.0001). The TTI of the inner retina layers(P<0.0001), ganglion cell layer(P<0.0001), inner plexiform layer(P<0.0001), inner nuclear layer(P<0.0001), and outer nuclear layer(P<0.0001) were significantly higher in the XLAS group. The central RT of the XLAS group was significantly thinner than that of the control group(P<0.0001).CONCLUSION: Temporal retinal thinning appears early in XLAS patients, especially in male patients. The thinningis mainly caused by structural abnormalities of the inner retina. This suggests that temporal retinal thinning could be helpful for the early diagnosis and follow-up of XLAS with noninvasive SD-OCT examination.
文摘AIM:To evaluate the effect of vitamin B12 deficiency anemia(BDA)on peripapillary retinal nerve fiber layer thickness(RNFLT)using spectral domain optical coherence tomography(SD-OCT),and to determine any correlation arising thereof.METHODS:In this cross-sectional observational study,99 eyes of 50 BDA patients of age 18-65 y were compared with 100 eyes of 50 healthy control subjects.All subjects underwent comprehensive clinical,ophthalmic,and hematological evaluation,followed by peripapillary RNFLT assessment using SD-OCT.RESULTS:The mean total,inferior,nasal,and temporal RNFLT were significantly lower in BDA group as compared to control group(P<0.05).The mean total,inferior and nasal RNFLT correlated significantly(P<0.05)with serum Hb%,B12 and mean corpuscular volume(MCV)level(r=0.310,0.435,-0.386 for total;r=0.932,0.481,-0.513 for inferior;r=0.344,0.254,-0.233 for nasal;respectively),while temporal and superior RNFLT quadrant did not show any correlation with any of the hematological parameters(r=0.144,0.167,-0.096;r=0.111,0.070,-0.099;respectively).The mean total RNFLT showed progressive thinning at par with the progression of anemia,except in very severe BDA,where an inverse relationship was documented.CONCLUSION:The mean total,inferior,nasal,and temporal peripapillary RNFLT was significantly thinner in BDA patients.Peripapillary RNFLT thinning seemed to proceed at par with the progression of severity of anemia,except in very sever grade.Early assessment of peripapillary RNFLT may be crucial in BDA patients to prevent potential blinding sequelae.Peripapillary RNFLT thinning in BDA patients should be considered in the differential diagnosis of other non-glaucomatous optic neuropathies,as well.
