Unified deep learning model for predicting fundus fluorescein angiography image from fundus structure image

The prediction of fundus fluorescein angiography(FFA)images from fundus structural images is a cutting-edge research topic in ophthalmological image processing.Prediction comprises estimating FFA from fundus camera imaging,single-phase FFA from scanning laser ophthalmoscopy(SLO),and three-phase FFA also from SLO.Although many deep learning models are available,a single model can only perform one or two of these prediction tasks.To accomplish three prediction tasks using a unified method,we propose a unified deep learning model for predicting FFA images from fundus structure images using a supervised generative adversarial network.The three prediction tasks are processed as follows:data preparation,network training under FFA supervision,and FFA image prediction from fundus structure images on a test set.By comparing the FFA images predicted by our model,pix2pix,and CycleGAN,we demonstrate the remarkable progress achieved by our proposal.The high performance of our model is validated in terms of the peak signal-to-noise ratio,structural similarity index,and mean squared error.

Fundus photography,fundus fluorescein angiography,and optical coherence tomography of healthy cynomolgus monkey,New Zealand rabbit,Sprague Dawley rat,and BALB/c mouse retinas

Background:A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis.The choice of animal model is based on the measurability of specific parameters or structures,the applicability of clinical measurement technologies,and the similarity to human eye function.Studies of eye pathology usually compare optical parameters between a healthy and altered state,so accurate baseline assessments are critical,but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models.Methods:Three cynomolgus monkeys,six New Zealand rabbits,ten Sprague Dawley(SD)rats,and BALB/c mice were examined by fundus photography(FP),fundus fluorescein angiography(FFA),and optical coherence tomography(OCT).Results:Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP,FFA,and OCT.New Zealand rabbits have large eyeballs,but they have large optic disc and myelinated retinal nerve fibers in their retinas,and the growth pattern of retinal vessels were also different to the human retinas.Unlike monkeys and rabbits,the retinal vessels of SD rats and BALB/c mice were widely distributed and clear.The OCT performance of them were similar with human beings except the macular.Conclusions:Monkey is a good model to study changes in retinal structure associated with fundus disease,rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases,and rats and mice are good models for retinal vascular diseases.These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.

Comparison of fundus fluorescein angiography and fundus photography grading criteria for early diabetic retinopathy

AIM:To compare the assessment outcomes of the characteristics of mild to moderate non-proliferative diabetic retinopathy(NPDR) established by fundus photography and fundus fluorescein angiography(FFA).METHODS:The fundus photos and FFA results of 260 patients with diabetes mellitus were reviewed.Diabetic retinopathy(DR) severity was graded based on the international classification standard.The microaneurysms,hemorrhages,and intraretinal microvascular abnormalities(IRMA) in FFA images of patients with mild to moderate NPDR were observed.The differences between the fundus photos and the FFA results were summarized,analyzed,and compared.RESULTS:The counting of intraretinal hemorrhages identified by FFA revealed that only 9 eyes(1.9%) had more than 20 intraretinal hemorrhages in all four quadrants;15 eyes(3.1%) had more than 20 intraretinal hemorrhages in three quadrants;26 eyes(5.4%) had over 20 intraretinal hemorrhages in two quadrants;and 37 eyes(7.7%) had more than 20 intraretinal hemorrhages in only one quadrant.Furthermore,the number of IRMAs appeared ≥4 in 17 eyes,3 in 35 eyes,2 in 69 eyes,and 1 in 93 eyes.CONCLUSION:FFA has higher detection accuracy of retinal angiopathy than fundus photography.FFA grading results are helpful for timely detection and proper treatment of lesions easily missed by fundus photography.

Can Fundus Fluorescein Angiography be Performed for Diabetic Patients on Oral Metformin

Metformin is a kind of biguanide hypoglycemic agent that has been widely used in patients with diabetes mellitus. In clinical practice, whether metformin should be stopped before Fundus fluorescein angiography （FFA） remains largely unclear. Some endocrinologists suggest stop metformin before FFA. However, ophthalmologists do not always adopt this opinion in their practice. This situation may lead to disputes between physicians and patients. This article analyzed contrast-induced nephropathy（CIN） and the related contrast agent, as well as the adverse reactions of fluorescein angiography. It pointed out that the discrepancy may be caused by misunderstanding of contrast agents used in FFA. For angiography using iodine contrast agent, metformin must be stopped because of the increased possibility of CIN, while for FFA using fluorescein sodium, no CIN has been reported yet. Therefore, the authors believe FFA is safe for diabetic patients with oral metformin and it is unnecessary to stop metformin before the examination.

Fundus autofluorescence in central serous chorioretinopathy: association with spectral-domain optical coherence tomography and fluorescein angiography

and FA for identifying pathological abnormalities in CSC. The characteristics of IA AF in CSC were attributable to the modification of melanin in the RPE. IR- AIM: To evaluate the correlation among changes in fundus autofluorescence (AF) measured using infrared fundus AF (IR -AF) and short-wave length fundus AF (SW -AF) with changes in spectral -domain optical coherence tomography (SD -OCT) and fluorescein angiography (FA) in central serous chorioretinopathy (CSC). METHODS: Two hundred and twenty consecutive patients with CSC were included. In addition to AF, patients were assessed by means of SD -OCT and FA. Abnormalities in images of IA -AF, SW -AF, FA were analyzed and correlated with the corresponding outer retinal alterations in SD-OCT findings. RESULTS: Eyes with abnormalities on either IR-AF or SW-AF were found in 256 eyes (58.18%), among them 256 eyes (100%) showed abnormal IR -AF, but SW-AF abnormalities were present only in 213 eyes (83.20%). The hypo-IR-AF corresponded to accumulation of subretinal liquid, collapse of retinal pigment epithelium (APE) or detachment of APE with or without RPE leakage point in the corresponding area. The hyper -IR -AF corresponded to the area with loss of the ellipsoid portion of the inner segments and sub -sensory retinal deposits or focal melanogenesis under sensory retina. The hypo-SW-AF corresponded to accumulation of subretinal liquid or atrophy of RPE. The hyper -SW -AF associated with sub -sensory retinal deposits, detachment of RPE and focal melanogenesis. CONCLUSION: IR-AF was more sensitive than SW-AF AF should be used as a common diagnostic tool for identifying pathological lesion in CSC.

Fundus photography,fluorescein angiography,optical coherence tomography and electroretinography of preclinical animal models of ocular diseases

The eye is an immune-privileged and sensory organ in humans and animals.Anatomical,physiological,and pathobiological features share significant similarities across divergent species(1).Each compartment of the eye has a unique structure and function.The anterior and posterior compartments of the eye contain endothelium(cornea),epithelium(cornea,ciliary body,iris),muscle(ciliary body),vitreous and neuronal(retina)tissues,which make the eye suitable to evaluate efficacy and safety of tissue specific drugs(2).

Risk factors for adverse reactions of fundus fluorescein angiography

Background:To explore the difference between the outcomes of correlations between a series of variables and adverse reactions(ARs)to fluorescein from univariate and multivariate analysis and to evaluate the nausea effects in different age groups.Methods:A retrospective study of patients undergoing consecutive fluorescein angiography between March2010 and February 2012 was conducted.No patients were excluded on the ground of age,presence of atopy,allergy history,previous procedures without severe allergic ARs,asymptomatic hypertension and kidney failure with serum creatinine levels lower than 250μmol/L or with renal dialysis.Results:A total of 829 patients were enrolled and 22.2%of them had ARs.The majority of reactions were nausea(12.1%)which occurred less when age became old(P<0.0001).When the correlations between a series of variables and ARs were assessed separately,age(P<0.0001),prior reactions(P<0.0001)and motion sickness(P=0.0062)were highly and cardio/cerebrovascular disease(P=0.0015),diabetes(P=0.0001)and renal disease(P=0.0219)were lowly related to ARs.However,when the correlations were assessed simultaneously,only age[odd ratio(OR)0.974;95%confidence interval(CI),0.962–0.986],prior reactions(OR 5.596;95%CI,2.083–15.029)and motion sickness(OR 4.849;95%CI,1.583–14.856)were statistically correlated with ARs.Conclusions:Fluorescein angiography is a safe procedure for patients who are relatively healthy but with a history of any systemic disease.Young age,prior reactions and motion sickness which are highly related to emetic events should be considered in the evaluation of ARs to fluorescein.

Comparison of 24×20 mm^(2) swept-source OCTA and fluorescein angiography for the evaluation of lesions in diabetic retinopathy

AIM: To compare ultra-widefield(24×20 mm^(2)) sweptsource optical coherence tomography angiography(SSOCTA) and fluorescein angiography(FA) in the evaluation of diabetic retinopathy(DR) lesions. METHODS: Forty-six eyes of 23 patients with treatmentna?ve DR were included at Peking University People’s Hospital from September 1, 2021, until December 31, 2021, as well as 23 age and gender matched healthy controls. Quantitative assessments of DR lesions on FA and SS-OCTA(superficial capillary plexus, SCP, 24×20 mm^(2)) were performed.RESULTS: Area of fovea avascular zone(FAZ) was larger in DR cases than controls(0.34±0.069 mm^(2) vs 0.287±0.108 mm^(2), P=0.006). In DR eyes, the mean FAZ area was 0.34±0.069 and 0.334±0.087 mm^(2) on SS-OCTA and FA, respectively(P=0.428), while the median FAZ perimeter was 2.382(IQR, 2.201-2.59) and 2.333(IQR, 2.138-2.6) mm on SS-OCTA and FA images(P=0.733). There was no significant difference in the size of the non-perfusion area(NPA) between the images on SS-OCTA and FA(12.389, IQR 4.96-28.3 and 11.125, IQR 5-28.31 mm^(2), P=0.197). The median total microaneurysm(MA) count was 35(IQR, 19-46) and 73(IQR, 43-93) on SS-OCTA and FA(P<0.001), respectively. No significant difference in intra-retinal microvascular abnormality(IRMA) and neovascularization (NV) count was found between the two techniques. The intraclass coefficient(ICCs) of all the parameters above indicated stable repeatability.CONCLUSION: Ultra-widefield SS-OCTA represents a reliable, noninvasive, and quantitative imaging technique in the assessment of microvasculature in DR, which offers a potential substitute for FA in DR evaluation.

Quantitative analysis of retinal vasculature in normal eyes using ultra-widefield fluorescein angiography

AIM:To quantify the area and density of retinal vascularity by ultra-widefield fluorescein angiography(UWFA).METHODS:In a retrospective study,UWFA images were obtained using an ultra-widefield imaging device in 42 normal eyes of 42 patients.Central and peripheral steered images were used to define the edge of retinal vasculature by a certified grader.The length from the center of the optic disc to the edge of retinal vascularity(RVL)in each quadrant and the total retinal vascular perfusion area(RVPA)were determined by the grader using OptosAdvance software.The density of retinal vascularity(RVD)was quantified in different zones of central-steered images using Image J software.RESULTS:Among 42 healthy eyes,the values for mean RVL in each quadrant were 19.007±0.781 mm(superior),18.467±0.869 mm(inferior),17.738±0.622 mm(nasal)and 24.241±1.336 mm(temporal).The mean RVPA was 1140.117±73.825 mm^(2).The mean RVD of the total retina was 4.850%±0.638%.RVD varied significantly between different retina zones(P<0.001),and significant differences existed in the RVD values for total retinal area in patients over 50 years old compared to those under 50 years old(P=0.033).No gender difference was found.CONCLUSION:The UWFA device can be a promising tool for analyzing the overall retinal vasculature and may provide a better understanding of retinal vascular morphology in normal eyes.Aging may be related to lower RVD.

Dynamic versus static ultra-widefield fluorescein angiography in eyes with diabetic retinopathy:a pilot prospective cross-sectional study

AIM:To analyze differences in ultra-widefield fluorescein angiography(UWFA)findings between dynamic and static images of eyes with diabetic retinopathy(DR).METHODS:This cross-sectional study included 28 eyes of 28 patients with DR undergoing UWFA.A series of UWFA images acquired from each patient were converted into a time-lapse video and used as a dynamic image.A single,clear,arteriovenous phase image was chosen as a static image.Non-perfusion index(NPI)and its correlation with vascular abnormalities in different zones were compared between dynamic and static UWFA imaging.RESULTS:NPI appeared to increase from the center to the far-periphery in both groups.Dynamic NPI was lower in the total retinal area(0.26 vs 0.29,P=0.009)and farperiphery(0.33 vs 0.36,adjusted P=0.042),which was contrary to the static NPI.Far-peripheral NPI was associated with intraretinal microvascular abnormality in the posterior area in both groups.CONCLUSION:Time-lapse dynamic UWFA imaging is a useful modality to differentially diagnose hypofluorescence in the most peripheral region.This modality could provide a reliable method for NPI measurement.

Application of non-mydriatic fundus photography-assisted telemedicine in diabetic retinopathy screening

BACKGROUND Early screening and accurate staging of diabetic retinopathy(DR)can reduce blindness risk in type 2 diabetes patients.DR’s complex pathogenesis involves many factors,making ophthalmologist screening alone insufficient for prevention and treatment.Often,endocrinologists are the first to see diabetic patients and thus should screen for retinopathy for early intervention.AIM To explore the efficacy of non-mydriatic fundus photography(NMFP)-enhanced telemedicine in assessing DR and its various stages.METHODS This retrospective study incorporated findings from an analysis of 93 diabetic patients,examining both NMFP-assisted telemedicine and fundus fluorescein angiography(FFA).It focused on assessing the concordance in DR detection between these two methodologies.Additionally,receiver operating characteristic(ROC)curves were generated to determine the optimal sensitivity and specificity of NMFP-assisted telemedicine,using FFA outcomes as the standard benchmark.RESULTS In the context of DR diagnosis and staging,the kappa coefficients for NMFPassisted telemedicine and FFA were recorded at 0.775 and 0.689 respectively,indicating substantial intermethod agreement.Moreover,the NMFP-assisted telemedicine’s predictive accuracy for positive FFA outcomes,as denoted by the area under the ROC curve,was remarkably high at 0.955,within a confidence interval of 0.914 to 0.995 and a statistically significant P-value of less than 0.001.This predictive model exhibited a specificity of 100%,a sensitivity of 90.9%,and a Youden index of 0.909.CONCLUSION NMFP-assisted telemedicine represents a pragmatic,objective,and precise modality for fundus examination,particularly applicable in the context of endocrinology inpatient care and primary healthcare settings for diabetic patients.Its implementation in these scenarios is of paramount significance,enhancing the clinical accuracy in the diagnosis and therapeutic management of DR.This methodology not only streamlines patient evaluation but also contributes substantially to the optimization of clinical outcomes in DR management.

Changes on optical coherence tomography angiography and fluorescein angiography in eyes with neovascular age-related macular degeneration

AIM:lo evaluate the changes on optical coherence tomography angiography(OCTA) and fluorescein angiography(FA) and their correlation in neovascular agerelated macular degeneration(nAMD) before and after intravitreal aflibercept injections(IAIs).METHODS:In 43 treatment-na?ve patients with nAMD,choroidal neovascularization(CNV) in OCTA were morphologically and quantitatively analyzed before and after IAIs to determine whether they are correlated with leakage on FA or not.By combining CNV in OCTA and leakage in FA,lesions were characterized as three types:L+C+(with both CNV and leakage),L-C+(with CNV but without leakage),or L+C-lesion(with leakage outside CNV).RESULTS:Before IAI,while 27 eyes had L+C+lesion only,16 eyes had both L+C+and L-C+lesions simultaneously.Tiny capillaries and anastomosis in CNV were more developed in L+C+lesion,at 86.0% and58.1%,respectively,relative to 9.3% and 9.3% in L-C+lesions(P<0.001).After IAIs in 33 eyes,tiny capillaries and anastomosis were decreased in the lesions with cessation of leakage on FA(P<0.001 and P=0.001,respectively).In quantitative analysis,neovascularization length and numbers of junctions and endpoints were also significantly decreased.CONCLUSION:Leakage on FA is associated with CNV morphology in OCTA and remained so after IAls.Therefore,by carefully assessing the morphological and quantitative changes of CNV in OCTA before and after treatment,activity of nAMD is expected even though CNV on OCTA is not completely matched with fluorescein leakage.

Fractal analysis of retinal vasculature in normal subjects on ultra-wide field fluorescein angiography

AIM: To evaluate the fractal feature of the retinal vasculature of normal eyes on a stereographic projected and montaged ultra-wide field(UWF) fluorescein angiography(FA).METHODS: Prospective, observational, cross-sectional study. Totally 59 eyes of 31 normal subjects were imaged using the Optos 200 Tx. Images obtained at different gaze angles stereographically projected and montaged. The early-phase UWF FA frames were processed to segment the retinal vasculature and the results were exported as binary masks. The fractal dimension(FD) was calculated using the box-counting method.RESULTS: The global FD for the entire retina was 1.6±0.04, with no difference between males and females(1.59±0.04 vs 1.61±0.04, P=0.084) or between right and left eyes(1.6±0.04 vs 1.6±0.05, P=0.61). FD was nonuniformly distributed among four quadrants(P<0.001) and decreased as the distance from the fovea increased(P<0.001). A negative association was observed between FD and age(R=-0.37, P=0.006), and this relationship was observed in the posterior and mid-peripheral retina(P<0.05) but absent in far-periphery(P>0.05).CONCLUSION: Fractal geometry is non-uniformly distributed across the retina in normal eyes and decreases from the fovea to the far-periphery. Subjects with an older age tend to have a smaller FD, however, the FD in the farperiphery does not appear to be influenced by age.

Changes of Indocyanine Green and Fluorescein Angiography in Multiple Evanescent White-dot Syndrome: A Case Report

Purpose: To study the clinicopathological change on "Multiple Evanescent White-dot Syndrome (MEWDS)"through fundus angiogrphy analyses.Methods:Examing the case with fluorescein angiography (FFA) and indocyanine green angiography(ICGA), visual field and following up for 15 months.Results :There exist multiple white dots in the fundus photo and angiography. The changes on ICGA maintain longer than fundus photo and FFA. Papille may be edematous and macula could present with special hypofluorescent flecks.Conclusions:MEWDS has specific angiographic features. Its pathological changes involve deep retinal pigment epithelium(RPE) as well as choroidal capillaries. The prognosis of the visual acuity for MEWDS is very good.

Fluorescein angiography of retinal vascular involution after intravitreal injection of ranibizumab for retinopathy of prematurity

AIM: To describe the involution patterns of vessel growth of retina through fluorescein angiography(FA) of children, who had been under treatment up to 1 y previously intravitreal ranibizumab(IVR) as monotherapy for retinopathy of prematurity(ROP). METHODS: This is a retrospective study. The medical information and FA of 17 children(34 eyes) whose area of avascular retina from the ora serrata was more than two disc diameters(DD) were analyzed. RESULTS: Among 34 eyes, all were the presence of finger-shaped vessels and arteriolar-venular shunts(100%,34/34 eyes). Popcorn abnormalities were found in most of the eyes(94.1%, 32/34 eyes). Furthermore, in many cases(23.5%, 8/34 eyes), there were leakage persisting in the region of the junction between avascular and vascular retina. In contrast, just 2 eyes(5.9%) showed damage of retinal capillary bed and 3 eyes(8.8%) showed large area of retinal pigment epithelium(RPE) atrophy. CONCLUSION: Although IVR can be very effective in ROP, we should remain cautious as infants may remain avascular peripheral retinas and abnormal vessel. FA allows accurate visualization of vessel abnormalities in eyes with ROP, which will be helpful to affect assessment of disease activity and therapeutic effect.

Foveal avascular zone area and parafoveal vessel density measurements in different stages of diabetic retinopathy by optical coherence tomography angiography

AIM：To investigate foveal avascular zone（FAZ）and parafoveal vessel densities（PRVD）by means of optical coherence tomography angiography（OCTA）in diabetic patients with or without diabetic retinopathy（DR）and to assess the reproducibility of FAZ and PRVD measurements.METHODS：Sixty diabetic patients（60 eyes）with different stage of DR（graded according to the International Clinical Severity Scale for DR）and 20 healthy subjects underwent FAZ area and PRVD measurements using OCTA by two experienced examiners.FAZ area in all patients was also assessed using fluorescein angiography（FA）.RESULTS：In subject with proliferative DR and with moderate-severe non proliferative DR,FAZ area was significantly increased compared to healthy controls（P=0.025 and P=0.050 respectively measured with OCTA and P=0.025 and P=0.048 respectively measured with FA）.OCTA showed significantly less inter-observer variability compared to FA.Concordance correlation coefficient（CCC）for FAZ area measurements was 0.829（95%CI：0.736-0.891）P〈0.001 with FA and 1.000（95%CI：0.999-1.000）P〈0.001with OCTA.CCC was 0.834（95%CI：0.746-0.893）P〈0.001and 0.890（95%CI：0.828-0.930）P〈0.001 for parafoveal superficial and deep vessel density measurements,respectively.CONCLUSION：OCTA shows progressive increase of FAZ area and reduction of PRVD in both superficial and deep plexus at increasing DR severity.FAZ area and PRVD measurements using OCTA are highly reproducible.

Peripheral arterial filling time and peripheral retina fluorescence features in ultra-widefield angiography

AIM:To evaluate the peripheral arterial filling time(PAFT)and venous filling time(VFT)in eyes without known diseases that may influence filling process using ultra-widefield(UWF)fluorescein angiography(FA),and to review the peripheral retina fluorescence features.METHODS:A total of 30 eyes of 30 patients were retrospectively reviewed in this observational study.UWFFA was performed using Optos 200Tx.PAFT and VFT was recorded.The interval between the arterial or venous filling completion and the previous photo was documented.The appearance of the far peripheral retina was described as either granular background fluorescence or mottled fluorescent band or vascular leakage.Terminal vascular patterns was described as loop pattern or branching pattern.Microvascular abnormalities such as arteriovenous shunting,vessels crossing the horizontal raphe,right angle vessels,terminal networks,capillary nonperfusion,drusen or microaneurysms were evaluated.RESULTS:The normal limits of PAFT was 3.397-8.984s and 4.399-11.753s for VFT.The appearance of the far peripheral retina,defined as granular background(63%),mottled fluorescence(20%),or vascular leakage(17%),was symmetrical between both eyes.Capillary nonperfusion(23%)and microaneurysms(40%)were more frequently found in eyes with loop pattern than in eyes with branching pattern.Other peripheral signs such as right-angle vessels(73%),and terminal networks(80%)were commonly seen on UWF-FA in the normal peripheral retina.CONCLUSION:The main courses of retinal artery and vein filling time are overlapping with each other on UWF-FA.Notably,the arterial filling process is completed in the arteriovenous phase rather than the traditionally named arterial phase.There are various manifestations in the peripheral retina of normal eyes.

Selective and complementary use of Optical Coherence Tomography and Fluorescein Angiography in retinal practice

The current field of posterior pole and retinal imaging of the human eye has expanded into detailed analyses of the macula,retinal periphery,individual retinal layers,vitreoretinal interface,imaging of the choroid and the optic nerve head.The challenge in retinal imaging is the enduring pursuit of deeper penetration into tissues,increased resolution to the cellular level,and interpretation of observations.How much deeper can we go and with what resolution and reproducibility?These are fundamental questions for experts in search of novel imaging modalities.New discoveries may resolve existing controversies,but inevitably stimulate new questions.Emerging technologies in retinal imaging include adaptive optics retinal imaging and optical coherence tomography-based retinal angiography.In this review,the focus of our discussion will be the discrepancy between the findings(interpretation)of one imaging technology that do not agree or are not even found with a complementary technology.If a clearly seen abnormality is present with one technology but absent in another,what are the possible explanations?Following is a summary of key concepts of retinal and optic nerve imaging modalities and current controversies regarding their interpretation and/or limitations.

OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity

AIM:To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion(NA-CRAO)via optical coherence tomography angiography(OCTA)and analyze their correlation with visual acuity.METHODS:Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into:A type(mild n=29),B type(moderate n=27)and C type(severe n=6)based on the degree of visual loss,retinal edema,and arterial blood flow delay in fundus fluorescence angiography(FFA).Contralateral healthy eyes were used as the control group.Best-corrected visual acuity(BCVA),slit lamp microscopy,indirect ophthalmoscopy,fundus color photography,OCTA,and FFA were performed.Spearman’s correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual acuity.RESULTS:There were no statistically significant differences in age,gender,and intraocular pressure among the three types and the control group(P>0.05).Vessel density in deep capillary plexus(VD-DCP)significantly decreased(P<0.05)in all three types of NA-CRAO patients compared to the control group.Vessel density in superficial vascular plexus(VD-SVP)significantly decreased(P<0.05)in type A patients and choriocapillaris flow area significantly decreased(P<0.05)in type B and type C patients compared to the control group;while outer retinal flow areas significantly increased in the type A(P<0.05)and decreased in type C patients(P<0.05).The retinal thickness significantly increased in type C group(P<0.05).The VD-SVP at fovea in the type A was significantly lower than both of type B and C.The VD-SVP at nasal parafovea in type A and B was significantly lower than type C(P<0.05).The logMAR BCVA of type A was significantly better than that of type B and C groups(P<0.05).Spearman’s correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea(r=0.679,P=0.031)and nasal parafovea(r=0.826,P=0.013).CONCLUSION:OCTA is valuable for assessing retinal ischemia,and evaluating visual impairment.Deep retinal vasculature is commonly affected in all NA-CRAO types.VDSVPs at fovea and nasal parafovea can serve as reliable markers of visual impairment in NA-CRAO.

Characteristics of fundus autofluorescence in cystoid macular edema

Background Fundus autofluorescence （FAF） imaging is a fast and noninvasive technique developed over the last decade.The authors utilized fluorescent properties of lipofuscin to study the health and viability of the retinal pigment epithelium （RPE）-photoreceptor complex.Observing the intensity and distribution of FAF of various retinal diseases is helpful for ascertaining diagnosis and evaluating prognosis.In this study,we described the FAF characteristics of cystoid macular edema （CME）.Methods Sixty-two patients （70 eyes） with CME were subjected to FAF and fundus fluorescein angiography （FFA） by a confocal scanning laser ophthalmoscope （Heidelberg Retina Angiograph 2 （HRA2））.Characteristics of FAF images were compared with FFA images.Results FAF intensity in normal subjects was highest at the posterior pole and dipped at the fovea.All cases of CME showed fluorescein dye accumulated into honeycomb-like spaces in macular and formated a typical petaloid pattern or atypical petaloid pattern in the late phases of the angiography.Sixty-one eyes with CME on FAF images showed mild or moderate hyperautofluorescence petaloid pattern in fovea,the FAF patterns of these CME was perfectly corresponding with shape in their FFA images;nine eyes with CME secondary to exudative age related macular degeneration （AMD） showed expansion of the hypoautofluorescence without petaloid pattern in macula.Conclusion FAF imaging can be used as a new rapid,non-invasive and ancillary technique in the diagnosis of the majority of CME,except for AMD and small part of other fundus diseases.