Superficial Retina Research Articles

Superficial and Deep Foveal Avascular Zone Area Measurement in Healthy Subjects Using Two Different Spectral Domain Optical Coherence Tomography Angiography Devices.

PurposeTo compare the area of the foveal avascular zone (FAZ) in the superficial and deep retinal layers using two different spectral-domain optical coherence tomography angiography (OCTA) devices.MethodsA cross-sectional comparative study was conducted to obtain macular OCTA images from healthy subjects using Optovue RTVue XR Avanti (Optovue, Inc, Fremont, CA) and Spectralis HRA+OCTA (Heidelberg Engineering, Heidelberg, Germany). Two independent trained graders measured the FAZ area using automated slab segmentation. The FAZ area in the superficial and deep retinal layers were compared.ResultsTwenty-three eyes of 23 subjects were included. The graders agreement was excellent (0.86) for all measurements. The mean FAZ area was significantly larger at the superficial retinal layer as compared to the deep retinal layer on both devices (0.31 0.08 mm vs 0.26 0.08 mm in Optovue and 0.55 0.16 mm vs 0.36 0.13 mm in Spectralis, both P 0.001). The mean FAZ area was significantly greater in the superficial and deep retinal layers using Spectralis as compared to Optovue measurements (P 0.001 for both comparisons).ConclusionIn contrast to previous reports, the FAZ area was larger in the superficial retina as compared to deep retinal layers using updated software versions. Measurements from different devices cannot be used interchangeably.

Swept-source optical coherence tomography angiography findings in choroidal and retinal tumors.

Toreport the swept-source optical coherence tomography angiography (SS-OCTA) findings in choroidal and retinal tumors. A retrospectivenoncomparative interventional case series of 60 eyes having various choroidal and retinal tumors imaged with SS-OCTA (Topcon DR1 Triton Plus, Tokyo, Japan) between September 2018 and February 2020was conducted. Inclusion criteria were tumor thickness <4 mm, tumor base diameter <10 mm, and tumor location at the posterior pole. Choroidal nevi usually demonstrated well-defined borders, hyperreflective internal structure, and no outer retinal involvement on SS-OCTA. Choroidal melanoma, in contrast to nevi, usually had ill-defined borders (p = 0.018), mixed hyperreflective-hyporeflective or hyperreflectiveinternal structure (p = 0.014), and demonstrated outer retinal involvement (p < 0.001). Circumscribed choroidal hemangioma usually presented with well-defined borders, a hyperreflective internal tumor structure with multiple dilated interconnected tumor vessels intermixed with signal void areas representing connective tissue. Optic disc melanocytomas showeda hyporeflective plexus related to blocking of signal by the pigment and an intact radial peripapillary capillary network. There was flow on the surface and slightly deeper within the lesion on B-scan angiography overlay. Retinal astrocytic hamartomas had well-defined borders and a hyperreflective vascular plexus in the superficial and deep retina. Outer retina and choriocapillaris showed hyporeflective change due to shadowing/masking from calcium or high blood flow in the lesion. Each of the different retinal and choroidal tumors studied in this series presented with different SS-OCTA features to aid in the differential diagnosis of these conditions. Good quality images are obtained in patients with good fixation and tumors <3 mm in thickness located at the posterior pole.

Optical coherence tomography angiography in glaucoma.

Assessment of the vasculature within the optic nerve, peripapillary superficial retina, macula, and peripapillary choroid can be determined in glaucoma using optical coherence tomography angiography (OCTA). Decreased perfusion within the pre-laminar layer of the optic nerve has been correlated with glaucoma severity. The peripapillary superficial retinal vessel density allows diagnosis and detection of glaucoma progression in a manner similar to the peripapillary retinal nerve fiber layer (RNFL) thickness. Furthermore, decreased peripapillary vessel density of the intact hemiretina or unaffected eye of glaucomatous eyes suggests that vascular changes can occur prior to detectable visual field damage. The accuracy for glaucoma detection of the macular ganglion cell (MGC) thickness compared to macular vessel density has differed among studies. Several studies have reported reduction of macular vessel density as well as its ganglion cell thickness. Results of studies evaluating the parapapillary choroid have shown a greater prevalence of choroidal microvasculature dropout in glaucomatous eyes with a parapapillary gamma zone, which is associated with central visual field defects or glaucoma progression. It remains unclear whether the reduced vessel density in glaucoma is a primary event or secondary to glaucomatous damage. Further studies are warranted to elucidate this question.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FINDINGS OF MICROVASCULAR AND NEURAL CHANGES IN PRIMARY PULMONARY HYPERTENSION.

To investigate the microvascular and neural changes in primary pulmonary hypertension (PPH) patients compared with healthy controls. Forty-four eyes of 22 PPH patients were included in this observational clinical cohort study, and 44 eyes of 22 healthy participants were enrolled as controls. Optical coherence tomography angiography images were obtained from each participant using the RTVue XR Avanti device with AngioVue software 2.0. Regarding the total macular-associated vessel density, including that of the superficial and deep retina, the optic disk-associated capillary density, including that of the whole image, capillary density inside the disk, and the peripapillary region, was significantly lower in the PPH group than in the control group. There was a similar trend in the retinal nerve fiber layer thickness and the ganglion cell complex thickness, whereas the focal loss volume and the global loss volume were greater in the PPH group than the control group. Changes in the capillary density and thickness of the retina and the optic nerve head in PPH patients can be detected by optical coherence tomography angiography. Parameters including the macular-associated vessel density, optic disk-associated capillary density, retinal nerve fiber layer, ganglion cell complex, focal loss volume, and global loss volume may provide useful evidence for the early detection of microvascular and neural impairments in patients with PPH.

Alterations in optical coherence tomography angiography findings in patients with high myopia.

The aim of this study was to determine the macular changes using optical coherence tomography (OCT) and OCT-angiography (OCT-A) in eyes with high myopia. Determining the alterations in vascular structures can provide a clearer understanding of the pathophysiological mechanisms of this disease and help define new treatment options and preventive measures. Ninety-two patients with high myopia (axial length ≥ 26 mm) and 70 control cases without any known systemic or ocular diseases were enrolled in this prospective study. One eye of each patient was included in the statistical analyses. Retinal nerve fiber layer (RNFL) thickness and Early Treatment Diabetic Retinopathy Study (ETDRS) macula map values were lower in myopia compared with the controls. Both superior and inferior ganglion cell complex (GCC) thicknesses were significantly thinner in the high myopia compared with the controls (p < 0.001). Regarding the OCT-A findings, although superficial or deep foveal avascular zones (FAZ) did not significantly differ between the two groups, the density values of superficial and deep microvessels were significantly lower in the high myopia group compared with the control cases. In patients with high myopia, with an increase in the axial length and a decrease in RNFL and GCC thicknesses, the vascular densities of the superficial and deep retina were reduced in the macular region.

Quantitative Assessment of Retinal Capillary Vessel Density and Foveal Avascular Zone Area in Central Serous Chorioretinopathy Using OCTA

Purpose: To quantitatively assess the retinal capillary vessel density (VD) and foveal avascular zone (FAZ) area in acute and chronic central serous chorioretinopathy (CSC) patients compared to healthy subjects using optical coherence tomography angiography (OCTA) and determine their correlation with visual acuity (VA). Methods: This was a cross-sectional, case-control study. All subjects were divided into three groups: acute CSC, chronic CSC, and healthy controls. The best-corrected VA test, optical coherence tomography, and OCTA were performed on the same day. In this study, we recorded and compared the main data of FAZ and VD in 3 × 3 mm OCTA images among three groups, also calculated the correlation between OCTA variables and VA in CSC patients. Results: A total of 148 subjects (148 eyes) were included in this study, with 50 eyes in acute CSC, 48 eyes in chronic CSC, and 50 eyes in control groups. The mean age was 50.11 ± 8.14 years. Chronic CSC had the significantly lowest VD both on the superficial and deep retina and the largest FAZ (0.39 ± 0.13 mm²) compared to acute CSC and controls (all p < 0.05). There was no statistical difference between acute CSC and controls on VD or FAZ (both p > 0.05). In chronic CSC, both the decreased VD on deep retina and expanded FAZ were correlated with a worse VA (both p < 0.05). Conclusions: OCTA could serve as a reliable tool to evaluate different courses of CSC quantitively. In 3 × 3 mm OCTA images, both decreased VD and expanded FAZ were observed in chronic CSC patients.

The vascular densities of the macula and optic disc in normal eyes from children by optical coherence tomography angiography.

This study aims to describe the variation and characteristics of vessel density (VD) of the macula and optic disc in the normal eyes of children. This was a retrospective study where subjects aged 5-18years with normal eyes were enrolled. The macula and optic disc were scanned by optical coherence tomography angiography (OCTA). The influences of age, gender, and axial length (AL) on VD were analyzed. A total of 71 normal eyes from 71 subjects were enrolled. For the macula, the mean VD of fovea, parafovea, and perifovea at superficial retina and deep retina were 20.1%, 50.2%, 49.4%, 36.1%, 53.9%, and 48.1%, respectively. The mean foveal avascular zone (FAZ) was 0.277mm2. For optic disc, the mean VD of radial peripapillary capillary (RPC) and inside-disc areas were 51.8% and 51.7%, respectively. Significant differences were found between the superior-hemi and inferior-hemi VD of the superficial retinal parafovea, deep retinal perifovea, and perifovea. The fovea VD of the superficial and deep retina and FAZ areas were different between genders. The inside-disc VD was positively correlated with AL, while other VDs had no significant correlation with age and AL. The parafovea VD of the superficial retina, parafovea, and perifovea of the deep retina had superior-hemi VD; boys had a higher fovea VD and smaller FAZ area than those of girls, the macular VD and peripapillary RPC density were steady for 5-18year-olds. This study provided useful information for furthering the understanding of the development mode of vessel in children and the OCTA clinical applications in children.

Effects of intravitreal injection of human CD34+ bone marrow stem cells in a murine model of diabetic retinopathy

Human CD34 + stem cells are mobilized from bone marrow to sites of tissue ischemia and play an important role in tissue revascularization. This study used a murine model to test the hypothesis that intravitreal injection of human CD34 + stem cells harvested from bone marrow (BMSCs) can have protective effects in eyes with diabetic retinopathy. Streptozotocin-induced diabetic mice (C57BL/6J) were used as a model for diabetic retinopathy. Subcutaneous implantation of Alzet pump, loaded with Tacrolimus and Rapamycin, 5 days prior to intravitreal injection provided continuous systemic immunosuppression for the study duration to avoid rejection of human cells. Human CD34 + BMSCs were harvested from the mononuclear cell fraction of bone marrow from a healthy donor using magnetic beads. The CD34 + cells were labeled with enhanced green fluorescent protein (EGFP) using a lentiviral vector. The right eye of each mouse received an intravitreal injection of 50,000 EGFP-labeled CD34 + BMSCs or phosphate buffered saline (PBS). Simultaneous multimodal in vivo retinal imaging system consisting of fluorescent scanning laser ophthalmoscopy (enabling fluorescein angiography), optical coherence tomography (OCT) and OCT angiography was used to confirm the development of diabetic retinopathy and study the in vivo migration of the EGFP-labeled CD34 + BMSCs in the vitreous and retina following intravitreal injection. After imaging, the mice were euthanized, and the eyes were removed for immunohistochemistry. In addition, microarray analysis of the retina and retinal flat mount analysis of retinal vasculature were performed. The development of retinal microvascular changes consistent with diabetic retinopathy was visualized using fluorescein angiography and OCT angiography between 5 and 6 months after induction of diabetes in all diabetic mice. These retinal microvascular changes include areas of capillary nonperfusion and late leakage of fluorescein dye. Multimodal in vivo imaging and immunohistochemistry identified EGFP-labeled cells in the superficial retina and along retinal vasculature at 1 and 4 weeks following intravitreal cell injection. Microarray analysis showed changes in expression of 162 murine retinal genes following intravitreal CD34 + BMSC injection when compared to PBS-injected control. The major molecular pathways affected by intravitreal CD34 + BMSC injection in the murine retina included pathways implicated in the pathogenesis of diabetic retinopathy including Toll-like receptor, MAP kinase, oxidative stress, cellular development, assembly and organization pathways. At 4 weeks following intravitreal injection, retinal flat mount analysis showed preservation of the retinal vasculature in eyes injected with CD34 + BMSCs when compared to PBS-injected control. The study findings support the hypothesis that intravitreal injection of human CD34 + BMSCs results in retinal homing and integration of these human cells with preservation of the retinal vasculature in murine eyes with diabetic retinopathy.

The blood perfusion changes of peripapillary and macular vessels in patients with nonarteritic anterior ischemic optic neuropathy

Objective To observe the blood perfusion changes of peripapillary and macular vessels in patients with nonarteritic anterior ischaemic optic neuropathy (NAION). Methods Retrospective cohort study. Thirty-six eyes (19 affected eyes and 17 fellow eyes) of 19 patients with NAION diagnosed in People’s Hospital of Wuhan University from November 2017 to January 2019 were included in this study. There were 10 males and 9 females, with the mean age of 55.05±7.11 years. Forty eyes of 20 normal subjects matched with NAION patients were included as controls. BCVA, fundus color photography, SD-OCT and OCT angiography were performed in normal controls and repeated in NAION affected eyes at 1-2 weeks, 1-2 months, 3-5 months intervals. OCT quantitative measurements: average retinal nerve fiber layer thickness (aRNFL) of the disc and its superior values (sRNFL) and the inferior values (iRNFL), average ganglion cell complex thickness(aGCC) in macular region and its superior values (sGCC) and the inferior values (iGCC). OCTA quantitative measurements: average radial peripapillary capillary density (aRPC) and its superior values (sRPC) and the inferior values (iRPC), average vascular density of superficial retina (aSVD) in macular region and its superior values (sSVD) and the inferior values (iSVD), average vascular density of deep layer retina (aDVD), areas of foveal avascular zone (FAZ). The differences of OCT and OCTA quantitative measurements between NAION eyes and the fellow eyes and normal controls were comparatively analyzed. Independent sample t test, paired sample t test or nonparametric rank sum test were performed for comparison among three groups. Pearson or Spearman correlation analysis were used to analyze the correlation between RNFL and RPC, GCC and SVD, RNFL and GCC, RPC and SVD. Results At baseline, the aRNFL, aRPC and aDVD of NAION patients were significantly higher than those of normal controls. Compared with the fellow eyes, the aRNFL increased significantly and the aRPC decreased significantly in NAION affected eyes. The overall differences of aRNFL, aRPC, aGCC and aSVD at four intervals within NAION affected eyes were statistically significant (P<0.05). The average sRNFL, sRPC, sGCC and sSVD at 1-2 months interval were significantly lower than the average iRNFL, iRPC, iGCC and iSVD (P<0.05). Correlation analysis: at 1-2 months interval, aGCC was positively correlated with aSVD (r=0.482, P=0.037); at 3-5 months interval, aRNFL was positively correlated with aRPC(r=0.631, P=0.037). Conclusion There is a sectorial reduction of vascular density of peripapillary RPC and macular SVD with the disease progression of NAION. Key words: Optic neuropathy ischemic; Optic disk; Macula lutea; Regional blood flow; Tomography, optical coherence

Misery Perfusion, Diffusive Oxygen Shunting and Interarterial Watershed Infarction Underlie Oxygenation-Based Hypoperfusion Maculopathy

To describe and explain the entire range of acute ischemic macular damage that follows panretinal hypoperfusion from central retinal artery or vein occlusion. Perspective article. To correlate the fundoscopic, fluorescein angiographic, oximetric, and optical coherence tomographic (OCT) features developing within the posterior inner retina following incremental reductions in arteriovenous perfusion pressure across the retinal circulation. The spectrum of acute oxygenation-based hypoperfusion maculopathy (OHM) is consistent with that predictable from a modified Krogh cylinder model of tissue oxygenation. Diffusive oxygen shunting plays a significant role in the "artery-dominated" generation of ischemic signs during misery perfusion. Three major grades of OHM severity can be discerned according to the predominant oxygenation status of ganglion cells within the superficial inner retina, whether this is normoxic (OHM1), hypoxic (OHM2), or anoxic (OHM3). Densely opaque axoplasmic sentinels are arranged along normoxic/hypoxic interfaces in OHM2. In OHM1 and OHM2, relative hypermetabolism and interarterial watershed infarction of fundal interneurons (WIFI) underpin subtle middle-retinal opacification with periarterial sparing. The fundal signs are optimally displayed en face using autofluorescence imaging whereas cross-sectional OCT reveals Paques' plaque formation. An exquisite and supremely accessible exhibition of classical oxygen physiopathology unfolds in eyes with panretinal hypoperfusion courtesy of the transparent ocular media and the pattern of macular neuroretinal opacification that evolves as upstream tissues extract oxygen to the detriment of tissues downstream. Recent attempts to overrule the simple conceptual framework embodied in WIFI have no plausible anatomical nor physiological basis. Overreliance on OCT can result in misdiagnosis.

Optical Coherence Tomography Angiography of Optic Disc and Macula Vessel Density in Glaucoma and Healthy Eyes.

To study the microvascular density of the macular and optic nerve head in healthy and glaucoma subjects using optical coherence tomography angiography. We performed a cross-sectional cohort study on healthy subjects and patients with glaucoma. The AngioVue Enhanced Microvascular Imaging System was used to capture the optic nerve head and macula images during one visit. En face segment images of the macular and optic disc were studied in layers. Microvascular density of the optic nerve head and macula were quantified by the number of pixels measured by a novel in-house developed software. Areas under the receiver operating characteristic curves (AUROC) were used to determine the accuracy of differentiating between glaucoma and healthy subjects. A total of 24 (32 eyes) glaucoma subjects (57.5±9.5-y old) and 29 (58 eyes) age-matched controls (51.17±13.5-y old) were recruited. Optic disc and macula scans were performed showing a greater mean vessel density (VD) in healthy compared with glaucoma subjects. The control group had higher VD than the glaucoma group at the en face segmented layers of the optic disc (optic nerve head: 0.209±0.05 vs. 0.110±0.048, P<0.001; vitreoretinal interface: 0.086±0.045 vs. 0.052±0.034, P=0.001; radial peripapillary capillary: 0.146±0.040 vs. 0.053±0.036, P<0.001; and choroid: 0.228±0.074 vs. 0.165±0.062, P<0.001). Similarly, the VD at the macula was also greater in controls than glaucoma patients (superficial retina capillary plexus: 0.115±0.016 vs. 0.088±0.027, P<0.001; deep retina capillary plexus: 0.233±0.027 vs. 0.136±0.073, P<0.001; outer retinal capillary plexus: 0.190±0.057 vs. 0.136±0.105, P=0.036; and choriocapillaris: 0.225±0.053 vs. 0.153±0.068, P<0.001. The AUROC was highest for optic disc radial peripapillary capillary (0.96), followed by nerve head (0.92) and optic disc choroid (0.76). At the macula, the AUROC was highest for deep retina (0.86), followed by choroid (0.84), superficial retina (0.81), and outer retina (0.72). Microvascular density of the optic disc and macula in glaucoma patients was reduced compared with healthy controls. VD of both optic disc and macula had a high diagnostic ability in differentiating healthy and glaucoma eyes.

Optical coherence tomography angiography of the macula and optic nerve head: microvascular density and test-retest repeatability in normal subjects

BackgroundDespite the potential usefulness of optical coherence tomography angiography in retinal and optic disc conditions, the reliability of the imaging modality remains unclear. This study set out to measure the microvascular density of macula and optic disc by mean of optical coherence tomography angiography and report the repeatability of the vessel density measurements.MethodsCross sectional observational cohort study. Subjects with normal eyes were recruited. Two sets of optical coherence tomography angiography images of macula and optic nerve head were acquired during one visit. Novel in-house developed software was used to count the pixels in each images and to compute the microvessel density of the macula and optic disc. Data were analysed to determine the measurement repeatability.ResultsA total of 176 eyes from 88 consecutive normal subjects were recruited. For macular images, the mean vessel density at superficial retina, deep retina, outer retina and choriocapillaries segment was OD 0.113 and OS 0.111, OD 0.239 and OS 0.230, OD 0.179 and OS 0.164, OD 0.237 and OS 0.215 respectively. For optic disc images, mean vessel density at vitreoretinal interface, radial peripapillary capillary, superficial nerve head and disc segment at the level of choroid were OD 0.084 and OS 0.085, OD 0.140 and OS 0.138, OD 0.216 and OS 0.209, OD 0.227 and OS 0.236 respectively. The measurement repeatability tests showed that the coefficient of variation of macular scans, for right and left eyes, ranged from 6.4 to 31.1% and 5.3 to 59.4%. Likewise, the coefficient of variation of optic disc scans, for right and left eyes, ranged from 14.3 to 77.4% and 13.5 to 75.3%.ConclusionsOptical coherence tomography angiography is a useful modality to visualise the microvasculature plexus of macula and optic nerve head. The vessel density measurement of macular scan by mean of optical coherence tomography angiography demonstrated good repeatability. The optic disc scan, on the other hand, showed a higher coefficient of variation indicating a lower measurement repeatability than macular scan. Interpretation of optical coherence tomography angiography should take into account test-retest repeatability of the imaging system.Trial registrationNational Healthcare Group Domain Specific Review Board (NHG DSRB) Singapore. DSRB Reference: 2015/00301.

Swept-source optical coherence tomography and optical coherence tomography angiography in acquired toxoplasmic chorioretinitis: a case report

PurposeTo describe swept-source optical coherence tomography and optical coherence tomography angiography retinal changes in a case of acute toxoplasmic chorioretinitis both at the time of diagnosis and after healing.Case presentationA 57-year-old white woman suffering from acquired toxoplasmic chorioretinitis underwent swept-source optical coherence tomography and optical coherence tomography angiography both at the time of diagnosis and after healing. In the acute phase of the disease, swept-source optical coherence tomography clearly showed retinal and choroidal involvement in the superficial retina and in the choroidal swelling. Optical coherence tomography angiography showed a complete loss of deep and superficial capillary networks and of choroidal vessels in the area of the inflammation. After healing, swept-source optical coherence tomography showed a retinal thinning of the area involved, with a subversion of retinal layers and no visible change at the choroid level. On the other hand, optical coherence tomography angiography showed the persistence of a vascular occlusion at the retina and choroid level.ConclusionThis is the first case in the optical coherence tomography angiography literature that shows the imaging of toxoplasmic chorioretinal lesions. This case confirms the involvement of the retina and choroid in toxoplasmic uveitis and the disruptive potential of such inflammation. The optical coherence tomography angiography performed after healing showed a persistent ablation of the retina, choriocapillaris, and choroidal vessels. The non-invasive optical coherence tomography angiography imaging technique may have diagnostic and prognostic value in regard to toxoplasmic uveitis.

Evaluation of microvascular changes in the macular area of eyes with rhegmatogenous retinal detachment without macular involvement using swept-source optical coherence tomography angiography.

PurposeTo evaluate microvascular changes in the macular area of eyes with rhegmatogenous retinal detachment (RRD) without macular involvement (macula-on RRD) using swept-source optical coherence tomography angiography (SS-OCTA).Patients and methodsFive patients with macula-on RRD were eligible for analysis. All patients underwent SS-OCTA examination (Triton) for the macular area. The healthy fellow eyes were included as controls. The vessel density (VD) was calculated using binarization, and the foveal avascular zone (FAZ) was measured. The VD and FAZ area were compared between the eyes with RRD and the fellow eyes using the Wilcoxon signed rank test.ResultsThe patients’ clinical characteristics were as follows: age, 49.0 years (21.0, 54.0) (median [25, 75th percentile]); preoperative best-corrected visual acuity, −0.08 (−0.08, 0.11) for RRD and −0.08 (−0.08, −0.03) for the fellow eye (P=0.50); and axial length, 27.0 (25.1, 28.7) mm for RRD and 27.4 (25.6, 28.5) mm for the fellow eye (P=0.31). The parafoveal VD was not significantly different between the eyes with RRD and the fellow eyes (P=1.00 for the superficial retina and P=0.44 for the whole retina). The FAZ area was also similar for the eyes with RRD and the fellow eyes (P=0.31 for the superficial retina and P=0.13 for the whole retina).ConclusionThe findings of this study suggest that the macular microvasculature remains intact in eyes with macula-on RRD.

Optical coherence tomography angiography analysis of macular flow density in glaucoma.

Modifications in ocular blood flow may play a significant role in glaucoma development. Optical coherence tomography angiography (OCT-A) is based on the detection and analysis of the reflection behaviour of motion in a static environment and therefore is able to quantify the retinal flow density. We used this new technology to examine the density of the active flow vasculature in the macular area in glaucoma patients compared to healthy patients. Thirty patients with primary open-angle glaucoma (mean age: 72.6±7.1years) and 21 healthy patients (mean age: 70.3±8.6years) were recruited. Patients received perimetry and OCT measurements of the peripapillary retinal nerve fibre layer thickness (RNFLT) and macular retinal thickness and OCT-A of the macular area in the superficial and deep retinal (DR) plexus. Flow density of the OCT-A scan was calculated by binarisation and quantification of the pixel density. Macular flow density was globally and nasally reduced in glaucoma patients in the superficial (globally: p=0.0203; nasally: p=0.0003) and DR plexus (globally: p=0.0113, nasally: p<0.0001). There was no significant difference between the superficial retina and the DR concerning the flow density. Flow density showed no significant correlation with perimetry results, RNFLT or retinal segment thickness. Patients with glaucoma exhibit a reduced macular flow density measured by OCT-A compared to controls. The independence of the macular flow density of the retinal segment thickness changes could indicate an altered vascular element in patients with glaucoma.

Progressive Retinal Thinning in Sickle Cell Retinopathy

To determine the rate of retinal thinning on spectral-domain (SD) OCT in patients with sickle cell compared with controls. Retrospective, longitudinal study. Patients with sickle cell and age-similar control patients with SD-OCT macula volume scans at least 10 months apart were reviewed. Automated segmentation of the SD-OCT macula volume scans was performed using the Iowa Reference Algorithms to divide the retina into 3 combined retina layers: superficial (retinal nerve fiber layer and ganglion cell layer), middle (inner plexiform layer and inner nuclear layer), and outer (outer plexiform layer to retinal pigment epithelium). The mean retinal thickness in each Early Treatment Diabetic Retinopathy Study (ETDRS) subfield was recorded. The rate of retinal thickness change was calculated using a multilevel mixed-effects model. The rate of retinal thickness change in the superficial, middle, and outer retina. Thirty-eight eyes of 24 patients with sickle cell (age: mean 40 years, range 18-67 years; genotype: 12 hemoglobin SS, 11 hemoglobin SC, 1 not available) and 30 eyes of 30 control patients were followed on average for 25.5 months. The mean initial retinal thickness was thinner in the sickle cell group compared with the control group (superficial: 69.95 vs. 72.22 μm; middle: 65.24 vs. 71.22 μm; outer: 171.37 vs. 175.55 μm). The mean rate of retinal thinning was greater for the sickle cell group than the control group (superficial:-0.89 vs.-0.41 μm/year; middle:-0.45 vs.+0.18 μm/year; outer:-0.50 vs.-0.02 μm/year). The rate of thinning in patients with sickle cell was statistically significant (P < 0.05) for the superficial retina in the center subfield and nasal and temporal inner subfields, as well as the middle retina in the temporal inner subfield. Compared with controls, there was a faster rate of retinal thinning for the middle retina in the temporal inner subfield. Rates of retinal thinning were similar regardless of whether qualitative areas of focal retinal thinning were seen on initial imaging. Patients with sickle cell exhibit a progressive retinal thinning predominantly affecting the superficial and middle retina that may represent chronic microvascular insult.

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

BackgroundThere are two forms of system implementation of optical coherence tomography angiography (OCTA) in ophthalmic imaging, i.e., spectral domain (SD-) and swept source OCTA (SS-OCTA). The purpose of this paper is to compare the SD-OCTA and SS-OCTA for elucidating structural and vascular features associated with central serous retinopathy (CSR), and to evaluate the effects of CSR on SD- and SS-OCTA’s imaging capabilities.MethodsNormal subjects and CSR patients were imaged by SD- and SS-OCTA using 3 × 3 mm and 6 × 6 mm scan patterns. OCT signal strengths at the superficial retina, deep retina, Sattler’s layer and Haller’s layer were used to compare the ability of SD- and SS-OCTA to image structural features. In addition, the ability to acquire angiograms were discussed by evaluating retinal vessel density. Central serous volume (CSV) was measured and it was correlated with difference in signal strengths (∆S) between two OCTA devices.ResultsSeven normal eyes and seven diseased eyes were recruited. Results showed no significant differences between SD- and SS-OCT in detecting structural features of the retinal layer according to the paired t-test. However, when imaging the Sattler’s layer for normal eyes, a significant difference is found between SD- and SS-OCT (p < 0.0001 for 3 × 3 mm scan, and p = 0.0002 for 6 × 6 mm); while for CSR eyes, the corresponding values were p < 0.0001 and p = 0.0003, respectively. At Haller’s layer for normal eyes, the corresponding values were p = 0.0004 and p = 0.0014; and for CSR eyes, p = 0.0004 and p < 0.0001, respectively. A strong correlation between ∆S and CSV was observed in the Sattler’s layer (3 × 3 mm – p = 0.0031 and R2 = 0.951; 6 × 6 mm – p = 0.0075 and R2 = 0.911) and Haller’s layer (3 × 3 mm – p = 0.0026 and R2 = 0.955; 6 × 6 mm – p = 0.0013 and R2 = 0.972).ConclusionsThe results suggest no differences between SD- and SS-OCTA for imaging the retinal layers however, when imaging beyond retinal layers, SS-OCTA appears advantageous in detecting returning signals. In CSR cases, the CSV may have an impact on sub-CSR tissue imaging and appears to have more impact on SD- than SS-OCTA.

Comparison of confocal laser scanning colorful fundus imaging and color fundus photography for detection of diabetic retinopathy

Objective To compare the imaging characteristics and detection of various types of lesions in diabetic retinopathy (DR) with colorful laser scanning fundus imaging (MSLI) and traditional color fundus photography (CFP). Methods Prospective case series observational study. A total of 38 eyes of 38 patients with DR diagnosed by clinical examination were included in the study. Among them, 21 were male and 17 were female; the mean age was 62.6±11.2 years; the average duration of diabetes was 14.3±7.5 years. All the patients were performed CFP, MSLI, frequency domain optical coherence tomography (SD-OCT), fluorescein angiography (FFA) examination. Using the Helielberg Spectralis HRA+OCT MSLI inspection, one scan simultaneously obtained 488 nm blue reflection (BR), 515 nm green light reflection (GR), 820 nm infrared light reflection (IR), and multicolor image (MC). The detection of traditional CFP and MC on microaneurysm (MA), hard exudation (HEX), cotton plaque (CWS), intraretinal hemorrhage (IRH), intraretinal microvascular abnormality (IRMA), venous bead (VB), venous ring (VL), macular edema (DME), macular anterior membrane (MEM) and laser photocoagulation (LB) were comparatively observed. The results of FFA examination were used as the diagnostic criteria for lesions. SD-OCT was used to determine the location and depth of lesions and the diagnostic reference for DME and MEM. Results The numbers of eyes with MA (χ2=10.460), DME (χ2=4.006), MEM (χ2=4.444) was significantly higher in MC than that of traditional CFP. But the number of eyes with IRH (χ2=0.103), CWS (χ2=1.515), HEX (χ2=0.227), IRMA (χ2=0.051), VB (χ2=0.001), VL (χ2=0.149), VH (χ2=0.693) and LB (χ2=0.720) were not statistically significant between two methods (P>0.05). The imaging quality of MSLI mode is obviously better than that of traditional CFP. Among them, GR imaging shows the best structural changes of superficial retina in MA, CWS, HEX, MEM, etc. IR imaging shows clear depth in deep retina such as LB. DME was green on MC and the weak low-reflection dark area was visible on the IR image, which were consistent with the DME range indicated by the SD-OCT examination. Conclusions Compared with the traditional CFP, the MSLI can clearly show the DR lesion. The number of checkouts is high on MA, DME and MEM by MC image. Key words: Diabetic retinopathy/diagnosis; Ophthalmoscopy; Microscopy, confocal; Tomography, optical coherence; Color fundus photography

Increase in the OCT angiographic peripapillary vessel density by ROCK inhibitor ripasudil instillation: a comparison with brimonidine

PurposeTo assess the responses of the superficial peripapillary retinal vessel density (VD) and prelaminar flow index (PLFI) to topical Rho-assisted coiled-coil forming protein kinase (ROCK) inhibitor ripasudil and alpha-2 agonist brimonidine using optical coherence tomography angiography.MethodsThis is a prospective, non-randomized, comparative cohort study. We studied the response of optical coherence tomography angiography (OCTA) parameters to drugs in 24 eyes treated with ripasudil and 23 eyes treated with brimonidine at the Sensho-kai Eye Institute. After division by the signal strength (SS), we compared the responses of peripapillary VD/SS and PLFI/unit area (UA)/SS to topical eye drops in eyes with primary open-angle glaucoma (POAG) and ocular hypertension (OH).ResultsIn the superficial peripapillary retina, VD/SS increased significantly in the ripasudil-treated eyes (12.5 ± 21.7%, P = 0.018), but not in the brimonidine-treated eyes (− 2.0 ± 13.8%, P = 0.484). In the deeper area of the optic disc, the changes in the PLFI/UA/SS in the brimonidine-treated eyes (+ 0.9 ± 8.9%, P = 1.00) and ripasudil-treated eyes (− 1.3 ± 8.5%, P = 0.241) were not significant. Multivariate discriminant analysis showed that the change in the peripapillary VD/SS was the most important parameter (P = 0.0186) for differentiating ripasudil- and brimonidine-treated eyes.ConclusionsThe topical ROCK inhibitor ripasudil enhanced the peripapillary VD in POAG and OH, whereas the alpha-2 agonist brimonidine did not. The PLFI did not respond to either drug.

Swept-Source OCT Angiography of Full-Thickness Macular Holes: Appearance and Artifacts.

To evaluate swept-source optical coherence tomography angiography (SS-OCTA) images in full-thickness macular holes (FTMHs). SS-OCTA of FTMHs was performed before or after surgery. Vitrectomy with the temporal inverted internal limiting membrane flap technique was used. The authors measured the diameter and area of the foveal avascular zone (FAZ) in superficial and deep retina vasculature. In 88 patients, two artifact types were observed. First, a hyperreflective circle in the center corresponding to a segmentation failure, as in these cases the segmentation line automatically relocated below the retinal pigment epithelium. Second, in macular holes with cystic spaces around the fovea, detection of blood flow was only partially possible, showing artifacts in the perifoveal vasculature. The authors present artifacts occurring during visualization of FTMHs with SS-OCTA and the means to correct them. Eyes with decreased postoperative central retinal thickness have an increased FAZ in the deep retinal layer plexus. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:111-121.].