Optical coherence tomography angiography (OCT-A) has enabled fast, non-invasive, high-resolution visualization of vasculature within the eye. In the past few years, it has become increasingly utilized for a range of disorders including age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, and uveitis among others. This article reviews technical aspects of OCT-A, its applications in chorioretinal disease, and known limitations of the technology.

Purpose : To assess the effect of axial length (AL) on the quantification of superficial vessel density of both macular and disc region using swept source optical coherence tomography angiography (SSOCTA). Methods : This is a cross-sectional clinical study. Seventy-five eyes from 75 Chinese healthy participants (56 females) with a mean age of 26.6±6.8 (range 19-50) years were included in this study. All eyes were imaged with SSOCTA, using a 3×3mm scan pattern centered on the macular and optic disc respectively, and the superficial layer was used for evaluation. The image size was corrected with AL using Bennett ...

Purpose : To report a new method to analyze sagittal images of the upper eyelid by anterior segment optical coherence tomography (AS-OCT). Methods : Ninety subjects equally divided into young (20–39 years), middle age (40–59 years), and elderly (60–79 years) group were studied. A sagittal image of the upper eyelid was obtained by AS-OCT (CASIA2, Tomey, Japan) and the following parameters were determined: upper eyelid thickness (UET), the distance between two parallel lines tangential to the apexes of the cornea and the upper eyelid; the upper eyelid angle (UEA) was the angle formed by a line running tangential to ...

Purpose : To evaluate artifacts in OCT-A images of multiple sclerosis (MS) patients and healthy controls. Materials and Methods : This was a prospective cross-sectional study conducted at the Department of Neurology and the Wilmer Eye Institute at Johns Hopkins Hospital. Subjects included patients with an established diagnosis of MS and healthy volunteers. OCT-A was performed using Spectralis® OCT-A prototype, OCT2 (Heidelberg, Germany). The type and frequency of artifacts, the clinical factors associated with them, and their impact on vessel density measurements were assessed. Results : Overall, 385 images from 102 participants were analyzed. The majority of images (97.1%) had some degree ...

Introduction : Multiple Sclerosis (MS) is the most common chronic autoimmune neuroinflammatory condition in young adults. It is often accompanied by optic neuritis (ON) and retinal neuro-axonal damage causing visual disturbances. Optical coherence tomography (OCT) is a sensitive non-invasive method for quantifying intraretinal layer volumes. Recently, OCT not only showed to be a reliable marker for ON-associated damage, but also proved its high prognostic value for functional outcome and disability accrual in patients with MS. Consequently, OCT is discussed as a potential marker for monitoring disease severity and therapeutic response in individual patients. Areas covered : This article summarizes our current understanding ...

Purpose : To study the role of Optical coherence tomography (OCT) Angiography (OCTA) in detecting retinal vascular and macular abnormalities as compared to Fundus Fluorescein Angiography (FFA) in subjects with Asteroid hyalosis (AH). Methods : In a prospective study, patients with AH underwent OCTA and FFA. AH graded as Grade 1 in 8 (optic disc, second order vessels visible), Grade 2 in 4 (optic disc, first-order vessels visible), Grade 3 in 11 (hazy view of optic disc) and Grade 4 (no view of fundus) in 2 eyes. Results : A total of 20 patients (25 eyes) with AH were included. In comparison to ...

Objective : The aim of this study was to investigate the multimodality imaging features of retinal cavernous hemangiomas (RCHs). Materials and Methods : The clinical data of three patients with RCH were reviewed and the imaging findings were analyzed. Results : The color photographs of the fundus showed bead-like vesicles in the retina. Some vesicles showed plasma erythrocyte separation—with plasma on the top and erythrocytes at the bottom—which was consistently detected as high spontaneous fluorescence on fundus fluorescence angiography. Other vesicles were surrounded by thick walls and fibrous tissue, showing high spontaneous fluorescence, although they did not show any changes on ...

Purpose : The aim of this study was to quantitatively compare both the vessel density of macular capillary plexuses and the foveal avascular zone (FAZ) areas of patients receiving hydroxychloroquine (HCQ) therapy for more than 5 years while using age- and sex- matched controls. Methods : The patients undergoing HCQ who were screened for toxic effects were evaluated. The FAZ parameters included the area, perimeter, and the acircularity index. The foveal density and vessel density values of both the superficial (SCP) and deep capillary plexuses (DCP) were measured using optical coherence tomography angiography (OCTA). Results : This study included 80 eyes of 40 ...

Purpose: To evaluate retinal nerve fiber layer thickness (RNFLT), ganglion cell layer thickness (GCLT), subfoveal choroidal thickness (SFCT) and central retinal thickness (CRT) in asthmatic children who were under inhaled corticosteroid treatment by using Swept-Source Optical Coherence Tomography (SS-OCT). Materials and Methods: Fifty-three children were prospectively analysed in the study. Group 1 included 31 asthmatic children and group 2 included 22 healthy children. Asthmatic children received a dose 250 μg daily of inhaled fluticasone propionate (Flexotide, GlaxoSmithKline, Middlesex, UK). Allergy parameters including, exposure to smoke, eosinophil count, percentage of eosinophils, Immunoglobuline (Ig) E levels, number of asthma attacks, number of ...

Purpose : To quantitatively measure the flow, non-flow, density, and foveal avascular zone (FAZ) assessment tool parameters of optical coherence tomography angiography (OCTA) in patients with non-ocular Behcet’s Disease (BD), and to compare the results with those obtained in healthy controls. Methods : FAZ parameters, flow area of choriocapillaris, and vessel density values of both superficial (SCP) and deep capillary plexuses (DCP) were measured using OCTA. Results : The FAZ area in SCP, FAZ area in full retinal vasculature, and FAZ perimeter were significantly higher and foveal density-300 was significantly lower in the BD group than in the control group (p = 0 ...

Purpose : This study aims to develop a nomogram to predict brain lesions in patients with complete or incomplete bitemporal hemianopia by combining results from optical coherence tomography (OCT) and visual field (VF) testing. Material and Methods : We reviewed the medical records of patients who underwent magnetic resonance imaging (MRI) to identify brain lesions due to bitemporal hemianopia between January 2010 and March 2017, retrospectively. The patients were divided into two groups based on MRI findings: brain-lesion (+) group that had brain lesions on MRI ( n = 63), and brain-lesion (-) group without brain lesions on MRI ( n = 16). We compared OCT and VF ...

Purpose: To correlate the anatomical extent of ocular surface toxicity due to colours using anterior segment optical coherence tomography with the clinical findings. Methods: Patients presenting to our emergency department with ocular colour toxicity during the Holi festival celebrations from 2 nd March 2018 to 5 th March 2018 were assessed for any adnexal, conjunctival, corneal and anterior chamber findings, as well as findings on anterior segment optical coherence tomography (ASOCT). Results: A total of 21 patients were observed. The average age was 23 years with 16 patients being male (76.19%). Bilateral ocular involvement was more common (in 13 ...

Background: Huntington’s disease (HD) is a genetic, rare and progressive neurodegenerative disorder that causes motor and cognitive impairment in midlife patients. Although retinal damage was observed in animal HD models and in patients with other neurodegenerative diseases, we still need confirmation of impairment in HD patients. Optical Coherence Tomography (OCT) is a non-invasive methodology that analyzes the retinal nerve fiber layers (RNFL) and could reflect processes of neurodegeneration. Methods: A cross-sectional study with 14 HD patients who underwent a spectral domain OCT. Results were compared with a control group. Demographic data was also obtained. Results: Temporal and superior RNFL ...

ackground : To evaluate diurnal variations in macular schisis cavities in patients with X-linked juvenile retinoschisis (XLRS) with pathogenic variants in the RS1 gene using spectral-domain optical coherence tomography (SD-OCT). Methods : Three consecutive patients with a clinical diagnosis of XLRS and pathogenic variants in the RS1 , treated with carbonic anhydrase inhibitors (CAIs). Observational procedures : SD-OCT scans of the macula were acquired at 9 a.m., 1 p.m., and 4 p.m. within 24 h. Results : All patients demonstrated increased measures of central foveal thickness in the morning with gradual decrease through the day (9–43%). Major changes were observed between ...

Arteriovenous fistulas (AVFs) are abnormal shunts between the arterial and venous vascular systems. These usually produce ocular pain, increased intraocular pressure (IOP), and diplopia. Less frequently, they may cause retinal changes with visual impairment. Our purpose is to illustrate different retinal manifestations of AVF. We report the multimodal imaging study of three cases with retinal changes due to AVF, showing neurosensory retinal detachment, macular oedema, and macular ischemia. In conclusion, AVF may appear with different ophthalmic alterations. While usually increased IOP and diplopia are our main concerns, retinal study is mandatory, since a myriad of morphologic abnormalities might be present.

Rapid improvements in optical coherence tomography (OCT) technology have allowed for enhancement of both image resolution and scanning speed, and the development of vascular assessment modality. Optical coherence tomography angiography (OCTA) is the non-invasive in vivo imaging of the vasculature located within the retina and optic nerve head area. The principle of OCTA is to use the variations in OCT signals caused by moving particles as the contrast mechanism for imaging of flow. Several algorithms which aim to maximize the contrast signal and minimize the noise have been developed including the phase-based techniques, intensity-based techniques (e.g., split-spectrum amplitude decorrelation ...

Introduction Idiopathic epiretinal membrane (ERM) is a proliferation of cells formed on the internal surface of the retina and may cause a slow decrease in visual acuity (VA). The aim of this study was to evaluate the individual layers of the retina by optical coherence tomography (OCT) before and after vitrectomy with ERM peeling in order to refine surgical decision-making. Methods Forty-seven eyes of 45 patients (aged 55–87 years) with ERM were enrolled retrospectively from a tertiary referral centre. OCT examination was performed preoperatively and at a mean of 3.2 months postoperatively in all cases. Nine retinal surfaces ...

To determine normal values, repeatability, and interocular symmetry of optic nerve head measurements, three spectral-domain optical coherence tomography (SD-OCT) scans were obtained from 128 healthy Turkish children aged 5–17 years consecutively and prospectively. The mean disc area, rim area, cup volume, cup to disc area ratio, and vertical and horizontal cup to disc ratios were 2.30 ± 0.42 mm 2 , 1.84 ± 0.45 mm 2 , 0.09 ± 0.10 mm 3 , 0.20 ± 0.13, 0.37 ± 0.17, and 0.45 ± 0.20, respectively. The intraclass correlation coefficients were >0.9 for repeatability and >0.75 ...

Purpose : To evaluate the ability of new Swept source (SS) optical coherence tomography (OCT) technology to detect changes in retinal and choroidal thickness in patients with Parkinson’s disease (PD). Design : Observational case–control cross sectional study, developed from January to May 2016. Methods : In total, 50 eyes from 50 patients diagnosed with PD and 54 eyes of 54 healthy controls underwent retinal and choroidal assessment using SS DRI Triton OCT (Topcon), using the 3D Wide protocol. Total macular thickness and peripapillary data (retinal, ganglion cell layer [GCL+, GCL++] and retinal nerve fiber layer [RNFL] thickness) were analyzed. Macular and ...

Introduction : Diabetic retinopathy (DR) is a common complication of diabetes and a leading cause of blindness in working age population. Fluorescein angiography is still the gold standard in the evaluation of retinal vascular perfusion and diagnosis of macular ischemia. However, it is a costly, time-consuming procedure and it requires intravenous injection of contrast agent, exposing patients to potential side effects. Optical coherence tomography angiography (OCTA) is a novel, non-invasive imaging technique that provides dyeless visualization of blood flow in different retinal layers. Areas covered : An extensive review of the literature was performed to detail technical principles of OCTA and to ...

Purpose : To study the structural visibility of the posterior vitreous cavity and vitreoretinal interface using Spectral Domain–Optical Coherence Tomography in patients with uveitis using conventional, Enhanced Depth Imaging (EDI), Combined Depth Imaging (CDI), and Enhanced Vitreous Imaging (EVI) techniques. Methods : It was an observational cross-sectional study of 59 eyes of 33 patients between age group 12–72 years (Median 43) diagnosed as uveitis with posterior segment manifestations underwent OCT using conventional, EDI, CDI, and EVI techniques. The visibility of posterior vitreous was graded in all the techniques. Results : A statistically significant difference was seen in posterior vitreous visibility on ...

Purpose : To report a unique case series of acute syphilitic posterior placoid chorioretinopathy (ASPPC) correlating en-face optical coherence tomography (OCT) with standard imaging modalities. Methods : In this retrospective case series, multimodal imaging was performed in three ASPPC patients at the time of disease presentation. Results : Clinical and laboratory findings were consistent with the diagnosis of ASPPC. In all the study patients, multiple hyperreflective dot-like lesions distributed in the macular area and observed with en-face OCT at the level of retinal pigment epithelium (RPE) corresponded to the nodular RPE elevations on cross-sectional OCT and to the hyperautofluorescent spots on fundus autofluorescence ...

Purposes : To (i) evaluate variations in choroidal thickness (CT) and choroidal volume (CV) in diabetic macular edema (DME), as demonstrated by fluorescein angiography (FA) and enhanced depth-imaging (EDI) optical coherence tomography (OCT) (EDI-OCT) and (ii) correlate these variations with visual acuity. Methods : This study was a retrospective observational case series of patients with diabetic retinopathy (DR) and DME. The study groups comprised 77 DR patients ( n = 87), all of whom underwent color fundus photography, FA, and OCT on the same day. The control group comprised 25 age-matched healthy individuals ( n = 50 eyes). CT was measured by manual segmentation (EDI-OCT built-in ...

Purpose : To investigate the glaucoma diagnostic abilities of vessel density parameters as determined by optical coherence tomography (OCT) angiography in different stages of glaucoma. Materials and Methods : A total of 113 healthy eyes and 140 glaucomatous eyes were enrolled. Diagnostic abilities of the OCT vessel density parameters in the optic nerve head (ONH), peripapillary, and macular regions were evaluated by calculating the area under the receiver operation characteristic curves (AUCs). AUCs of the peripapillary vessel density parameters and circumpapillary retinal nerve fiber layer (RNFL) thickness were compared. Results : OCT angiography vessel densities in the ONH, peripapillary, and macular regions in ...