Comparison of quantitative measurement of foveal avascular zone and macular vessel density in eyes of children with amblyopia and healthy controls: an optical coherence tomography angiography study

Retinal microvascular changes in unilateral functional amblyopia detected by oct-angiography and follow-up during treatment

OBJECTIVE

To evaluate the macular microvascular changes using optical coherence tomographic angiography (OCT-A) in children with unilateral amblyopia and their reversibility during treatment.

METHODS

Patients with unilateral strabismic or anisometropic amblyopia or residual amblyopia from early congenital cataract surgery, examined between October 2019 and March 2021, were included. Vessel density and perfusion density in the superficial capillary plexus and area, perimeter and circularity of the foveal avascular zone (FAZ) were analysed using OCT-A in amblyopic eyes, contralateral eyes and control group healthy eyes. Correlation analyses between the microvascular parameters and the visual acuity were performed. In a pilot study on a few patients from the amblyopic cohort, longitudinal follow-up during treatment was also performed.

RESULTS

A total of 128 eyes of 64 patients were included: 32 amblyopic eyes compared with 32 contralateral eyes and 64 control eyes. Vessel density and perfusion density in the superficial capillary plexus were significantly lower in amblyopic eyes compared to control eyes in 6 × 6 mm (p < 0.02) and 3 × 3 mm (p < 0.01) scans. Correlation analyses showed a linear decrease in vessel density and perfusion density with decreasing visual acuity. The microvascular changes observed were reversible with the occlusion treatment of amblyopia (p < 0.001).

CONCLUSIONS

The study found a decrease in vessel density and perfusion density in the macula of children with unilateral functional amblyopia. These microvascular changes were correlated with visual acuity and appeared to be reversible with treatment of amblyopia. On the whole, OCT-A appears to be a relevant complementary examination when it comes to diagnosing and monitoring functional amblyopia.

Evaluation of Ganglion Cell-Layer Complex and Macular Vessel Density in Amblyopic Eyes with Optical Coherence Tomography Angiography

Purpose: This study aimed to compare and quantify the ganglion cell complex (GCC), macular thickness, and vessel density (VD) in amblyopic eyes and their corresponding fellow eyes using optical coherence tomography angiography (OCTA). Methods: This cross-sectional study analyzed 32 unilateral amblyopic patients, examining both of their eyes. The study assessed parameters such as GCC thickness, macular thickness (total, inner, and outer layers), and VD in the optic nerve and macular region using spectral-domain OCTA. Results: This study analyzed data from 30 unilateral amblyopic patients with a mean age of 28.7 ± 18.3 years. Amblyopic eyes had lower mean best-corrected visual acuity compared with healthy eyes. However, no significant differences were found in retinal nerve fiber layer (RNFL) thickness, GCC thickness, and overall retinal thickness between amblyopic and fellow eyes when accounting for factors such as axial length and signal strength index. In patients older than 30 years, amblyopic eyes had a higher global loss volume (GLV) compared with fellow eyes (p = 0.02). In addition, blood VD within the optic disc and superficial/deep capillary plexuses in different macular regions were significantly lower in amblyopic eyes compared with fellow eyes. Conclusions: This study found significant differences in VD and the GLV index between amblyopic eyes and healthy eyes, particularly in older patients. However, there were no notable differences in macular thickness and RNFL thickness. Further research is needed to determine the clinical relevance of these findings.

OCT-Angiography Findings in Children with Anisometropic Amblyopia

PURPOSE

The purpose of this prospective study is to show findings of OCT angiography in children with anisometropic amblyopia with a statistically significant difference, regardless of the type of refractive disorder, between the amblyopic and the fellow eye. This research aimed to establish whether there is a difference in vascular density [VD] and size of the foveal avascular zone [FAZ] in the superficial capillary plexus [SCP].

METHODS

All children between 9 and 18 years of age who were treated at the Outpatient Clinic for Orthoptics and Pleoptics of the Department of Ophthalmology, University Medical Centre Maribor from January 2020 to December 2022 due to unilateral anisometric amblyopia were enrolled in our study. Fourteen children met the criteria. Cirrus 5000 high-resolution OCT with AngioPlex OCT angiography was used to analyze the size of the FAZ and VD in the SCP and TCS. The paired t-test or Wilcox signed-rank test [p < 0.05] was used for statistical analysis of each parameter between the amblyopic and fellow eye.

RESULTS

Mean child age was 13 years ± 2.9 and ranged from 9 to 18 years. Most of the children [85.7%] were boys. The VD of the SCP did not show statistically significant differences between the visually impaired and control eyes [p = 0.328]. The comparison of the FAZ area between the two eyes was also not statistically significant [p < 0.808]. There was also no statistically significant difference in central macular thickness [TCS] [p < 0.291].

CONCLUSIONS

Our research results show no statistically significant differences in the VD and the FAZ of the SCP, and in the TCS between the amblyopic and fellow eye in children with unilateral anisometropic amblyopia. Our research did not confirm the results of certain previous studies in which a lower density of the capillary network was present in the visually impaired eye. Further studies with more children are necessary to confirm our results.

Assessment of macular microvascular changes in children following treatment of anisometropic myopic amblyopia using optical coherence tomography angiography

PURPOSE

To evaluate macular microvascular changes in the form of foveal avascular zone (FAZ) area and vessel density in the superficial, deep capillary plexuses, and choriocapillaris using optical coherence tomography angiography (OCTA) in children with anisometropic myopic amblyopia before and after treatment.

METHODS

This prospective observational study included 32 patients younger than 12 years old with anisomyopic amblyopia. OCTA was done before patients' treatment with optical correction with or without patching and was repeated after successful amblyopia treatment. Outcomes included superficial, deep, and choriocapillaris vessel density (VD) and superficial and deep FAZ areas.

RESULTS

The study included 13 males (40.6%) and 19 females (59.4%), and the mean age was 9.52 ± 1.33 years. Fifty-three percent (53%) of patients needed only optical correction, and the remaining 47% needed additional patching therapy. After successful treatment, there was a significant improvement in amblyopic eyes in best-corrected visual acuity (p < 0.001), with higher VD values in superficial capillary plexuses (p < 0.001), deep capillary plexuses (p < 0.001), and foveal choriocapillaris (p = 0.030). In the glasses with patching subgroup, the difference between pre-treatment and post-treatment parameters revealed a significant improvement in vessel density in superficial retinal plexuses (foveal and parafoveal; p values 0.023 and < 0.001, respectively) and deep retinal plexuses (whole image, foveal, and parafoveal; p values 0.003, < 0.001, and 0.002, respectively). While amblyopic eyes treated with glasses alone had a significantly greater difference in choriocapillaris foveal VD (p value = 0.022).

CONCLUSION

After effective amblyopia treatment, amblyopic eyes exhibited improved best-corrected visual acuity and better macular perfusion along the superficial, deep vascular density, and choriocapillaris foveal VD.

CLINICAL TRIAL REGISTRATION

CinicalTrials.gov Identifier: NCT05223153.

Evaluation of childhood developing via optical coherence tomography-angiography in Qamdo, Tibet, China: A prospective cross-sectional, school-based study

BACKGROUND

Optical coherence tomography angiography (OCTA) is a new and reliable machine used to evaluate retinal structure and macular perfusion in children. The use of OCTA under bad condition such as high altitude, low atmospheric oxygen, and low humidity, in children is rarely.

AIM

To quantify the macular micro-vasculature in healthy children of various ages using OCTA in Qamdo.

METHODS

Design: Prospective cross-sectional, school-based study. Three hundred and forty-seven normal students from 9 schools in 4 different areas in Qamdo were included. OCTA was performed on a 3 mm × 3 mm area centered on the macular region and macular cube 512 × 128 showed details in macular. Early treatment of diabetic retinopathy study Vessel Flow Density (VD) of the macular central vascular plexus density (CVD), inner vascular plexus density (IVD), full vascular plexus density (FVD), and the size of the foveal avascular zone (FAZ) were measured. All these results corrected by t/s = 3.382 × 0.01306 × (axial length-1.82). The differences were compared among various ages, sexes and living environments.

RESULTS

The mean FAZ area in all eyes was 0.27 mm2 ± 0.12 mm2. The mean foveal thickness (MFT) in the macular cube was 227.64 μm ± 23.51 μm. Compared with girls, boys had a lager FAZ (P = 0.0029). Among the different age groups, MFT (P < 0.001) and FVD (P < 0.0001), IVD (P < 0.0001), and CVD (P = 0.0050) increased with age. FAZ areas were not correlated with age (P = 0.8853) or others (MFT, area).

CONCLUSION

OCTA can use to evaluate macular perfusion in children. Our data bridge the gap between structural OCT and perfusion density in children in high altitude. Even though these were not a longitudinal study, it may provide us with hints about retina development during puberty and clinical implications of OCTA in children.

Macular superficial vascular density on optical coherence tomography angiography in children with unilateral anisometropic and bilateral hyperopic amblyopia

We analyzed whether macular superficial vascular density (SVD) and foveal vascular zone (FAZ) on optical coherence tomography angiography (OCTA) can distinguish between bilateral ametropic and anisometropic amblyopia. We included 42, 33, and 50 eyes in the bilateral ametropic amblyopia, anisometropic amblyopia, and normal control groups, respectively. Using macular swept-source optical coherence tomography angiography, we measured and analyzed the superficial FAZ areas and five sectoral macular SVDs after magnification correction. The anisometropic amblyopic eye group showed significantly increased foveal SVDs (p < 0.001) and significantly decreased superficial FAZ areas (p < 0.001), compared with the remaining groups. Additionally, the bilateral ametropic amblyopia group had significantly decreased nasal SVDs. SVDs and superficial FAZ areas differed among hyperopic amblyopia subtypes. These findings may reflect vascular distribution differences and macular changes in hyperopic amblyopia subtypes compared with normal eyes.

The Relationship between Fixation Stability and Retinal Structural Parameters in Children with Anisometropic, Strabismic and Mixed Amblyopia

(1) Background: Amblyopia is an ocular condition leading to structural and functional changes. The relationship between these changes is complex and remains poorly understood. (2) Methods: Participants included 31 children aged 5 to 9 years with strabismic (n = 9), anisometropic (n = 16) and mixed (n = 6) unilateral amblyopia, and 14 age-matched non-amblyopic children. The 95% and 63% Bivariate Contour Ellipse Area (BCEA), axial length, Foveal Avascular Zone (FAZ) area, center macular thickness and volume were assessed. The relationship between these parameters was explored. (3) Results: Statistically significant differences were found among the four groups in best corrected distance visual acuity (BCVA) (p < 0.001), BCEA 95% (p = 0.002) and BCEA 63% (p = 0.002), but not in the FAZ area, central macular thickness, central macular volume and axial length. Eyes with amblyopia had poorer BCVA and larger fixation instability than controls. Inter-ocular differences were more significant in patients with strabismic amblyopia, particularly in BCVA (p = 0.003), central macular thickness (p < 0.001) and central macular volume (p = 0.002). In amblyopic eyes, BCEA 95% and 63% were correlated with BCVA, but not with the FAZ area. (4) Conclusion: Amblyopia is associated with a reduction in fixation stability and BCVA, although there is a general lack of correlation with structural changes, suggesting a complex interaction between anatomy and function in amblyopia.

Inter-examiner and intra-examiner reliability of optical coherence tomography angiography in vascular density measurement of retinal and choriocapillaris plexuses in healthy children aged 6-15 years

Objective

This study aimed to test the inter-examiner and intra-examiner reliability of macular vascular density (VD) measurement of retinal and choriocapillaris plexuses in healthy children using optical coherence tomography angiography (OCTA).

Materials and methods

Ninety-two school children were prospectively recruited. Macular OCTA images (6 × 6 mm²) were obtained thrice by two examiners using the RTVue-XR Avanti OCT system. The coefficient of variation (COV), intraclass correlation coefficient (ICC), and Bland-Altman plots were used to evaluate the repeatability and reproducibility.

Results

Ninety participants aged 6-15 years were enrolled; two participants were excluded because of low-quality images. In the retina, the reproducibility and repeatability of VD became poorer from superficial to deep retinal capillary plexus (superficial: COV = 4.61-11.11%; intermediate: COV = 7.73-14.15%; deep: COV = 14.60-32.28%). For both reproducibility and repeatability, the ICC ranged from moderate to high (superficial plexus: ICC = 0.570-0.976; intermediate plexus: ICC = 0.720-0.968; deep plexus: ICC = 0.628-0.954). In the choroid, the inter-examiner reproducibility and intra-examiner repeatability of the VD measurement of choriocapillaris were excellent in the macula, fovea, parafovea, and perifovea (COV = 1.00-6.10%; ICC = 0.856-0.950). The parameters of the foveal avascular zone (FAZ) also showed significant reproducibility and repeatability (COV = 0.01-0.21%; ICC = 0.743-0.994).

Conclusion

The VD measurements of the choriocapillaris and FAZ parameters using OCTA showed excellent inter-examiner and intra-examiner reliability in school children. The reproducibility and repeatability of the VD of three retinal capillary plexuses depended on the depth of the retinal capillary plexus.

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Pediatric Retinal Diseases

Indirect ophthalmoscopy and handheld retinal imaging are the most common and traditional modalities for the evaluation and documentation of the pediatric fundus, especially for pre-verbal children. Optical coherence tomography (OCT) allows for in vivo visualization that resembles histology, and optical coherence tomography angiography (OCTA) allows for non-invasive depth-resolved imaging of the retinal vasculature. Both OCT and OCTA were extensively used and studied in adults, but not in children. The advent of prototype handheld OCT and OCTA have allowed for detailed imaging in younger infants and even neonates in the neonatal care intensive unit with retinopathy of prematurity (ROP). In this review, we discuss the use of OCTA and OCTA in various pediatric retinal diseases, including ROP, familial exudative vitreoretinopathy (FEVR), Coats disease and other less common diseases. For example, handheld portable OCT was shown to detect subclinical macular edema and incomplete foveal development in ROP, as well as subretinal exudation and fibrosis in Coats disease. Some challenges in the pediatric age group include the lack of a normative database and the difficulty in image registration for longitudinal comparison. We believe that technological improvements in the use of OCT and OCTA will improve our understanding and care of pediatric retina patients in the future.

Evaluation of Retinal Microvascular Features in Patients with Amblyopia Based on Optical Coherence Tomography Angiography: A Systematic Review and Meta-Analysis

BACKGROUND

The performance of optical coherence tomography angiography (OCTA) in macular microvasculature of patients with amblyopia has been widely studied, but these studies have yielded different and controversial results.

OBJECTIVES

The aim of this study is to investigate retinal microvascular features in patients with amblyopia undergoing OCTA.

METHODS

PubMed, Embase, and Web of Science were searched for published articles comparing the retinal microvascular features between individuals with amblyopia and controls until April 2022. The mean difference with a 95% confidence interval was used to assess continuous variables.

RESULTS

The analysis included 17 studies. The whole vessel density of the superficial capillary plexus (SCPVD) was lower in amblyopic eyes (AE) than in normal eyes (NE) in 3 × 3 mm2 scans, while the perifoveal vessel density of superficial and deep capillary plexus was lower in 6 × 6 mm2 scans. The whole, parafoveal vessel density of deep capillary plexus (DCPVD) and parafoveal SCPVD were lower in both scans. The comparison between AE and fellow eyes (FE) revealed no statistical difference in all quadrants except the parafoveal and perifoveal SCPVD and the foveal DCPVD. Additionally, SCPVD in all quadrants except the fovea and DCPVD in all quadrants except the parafoveal were higher in FE compared to NE. No significant difference was found in the foveal avascular area between AE and NE, AE and FE, or NE and FE.

CONCLUSIONS

The retinal vessel density of superficial and deep capillary plexus in AE and FE was lower than in NE, and differences were more likely discovered using 6 × 6 mm2 scans. Consequently, OCTA might be explored as a diagnostic tool to identify and monitor patients with amblyopia.

Evaluation of retinal microcirculation alterations using optical coherence tomography angiography in patients with hyperopia ametropic amblyopia: A case-control study

Given that there are controversial findings regarding vessel density in amblyopia, we quantified retinal microcirculation using optical coherence tomography angiography and compared it between hyperopic ametropic amblyopia eyes and age-matched control eyes. This case-control study was conducted from March 2021 to March 2022 at the Affiliated Eye Hospital of Nanchang University, Nanchang, China. Both groups included 72 eyes. Foveal avascular zone area, circularity and perimeter, perfusion density and vessel density of macular superficial retinal capillary plexus, macular thickness, macular volume, peripapillary retinal nerve fiber layer thickness, and ganglion cell-inner plexiform layer thickness were compared between hyperopia ametropic amblyopia eyes and age-matched control eyes. Additionally, best-corrected visual acuity, maximum corneal curvature, minimum corneal curvature, and anterior chamber depth were measured. In the hyperopia ametropic amblyopia eyes and control eyes, vessel density was 7.51 ± 2.13 and 9.91 ± 2.71 mm-1 in the central, 17.20 ± 1.38 and 18.25 ± 1.37 mm-1 in the inner, and 17.90 ± 0.88 and 18.43 ± 0.97 mm-1 in the full regions, respectively. The perfusion densities were 0.17 ± 0.06 and 0.23 ± 0.07 in the central, 0.41 ± 0.05 and 0.44 ± 0.03 in the inner, and 0.44 ± 0.03 and 0.46 ± 0.02 in the full regions, respectively. The central macular thicknesses of hyperopia ametropic amblyopia and control eyes were 240.04 ± 20.11 and 235.08 ± 24.41 µm, respectively. Foveal avascular zone perimeter and circularity (P < .043 and P = .001) significantly differed between the 2 groups. Hyperopia ametropic amblyopia eyes showed lower appreciably in vessel and perfusion densities, which could be one of the major pathophysiological mechanisms of hyperopia ametropic amblyopia and provide a new direction for the diagnosis and treatment of amblyopia.

Microvasculature evaluation of anisometropic amblyopia children by Angio-OCT

To compare and assess the choroidal and retinal microstructural vascularity in amblyopic eyes with the fellow eyes in anisometropic amblyopic children using angiography optical coherence tomography (Angio-OCT). Twenty-seven children (54 eyes; 5.59 ± 1.08 years old; 59.3% girls) were enrolled in this study. Choroidal thickness (CT) was measured with the use of the enhanced depth imaging mode in Angio-OCT. Parafoveal/peripapillary vascular density indices and the foveal avascular zone (FAZ) size were analyzed by MATLAB code programming on Angio-OCT images. The mean FAZ size of the amblyopic eyes were larger both in superficial and deep capillary plexus layer (SCPL/DCPL). Compared with the contralateral eyes (BCVA were normal), all the vascular density indices of SCPL and DCPL in the parafoveal and peripapillary zones were lower in the amblyopic eyes, however, the difference was insignificant (p > 0.05). No significant decrease was observed in four quadrants analyses of the amblyopic eyes (p > 0.05). Except for the measurement at 2000 µm and 1500 µm from the fovea in temple, CT in amblyopic eyes were significantly thicken than the fellow eyes (p < 0.05). Compared with the fellow eyes, the CT of certain areas were thicker in the amblyopic eyes. Though the FAZ size of the amblyopic eyes was larger in SCPL/DCPL layers, the retinal vascular density indices in SCPL/DCPL were lower in amblyopia eyes without statistical difference. Angio-OCT may be an effective way to evaluate the status of the choroidal and retinal vascular system in amblyopic children.

Ocular complications of diabetes mellitus in a pediatric population and proposals for screening and follow-up programs

Background

Diabetes mellitus (DM) is one of the world's greatest health emergencies of the 21st century. Ocular complications of DM are commonly chronic and progressive, but vision loss can be effectively prevented or delayed with early detection and timely treatment. Therefore, regular comprehensive ophthalmologic examinations are mandatory. Ophthalmic screening and dedicated follow-up for adults with DM are well established, whereas, there is no consensus on optimal recommendations for the pediatric population, reflecting the lack of clarity about the current burden of disease in this age group.

Objectives

To determine the epidemiology of ocular complications of diabetes and to assess optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) macular features in a pediatric population with DM. To review ophthalmological screening and follow-up plans for the diabetic pediatric population.

Design

Observational study.

Methods

Retrospective consecutive cohort study of all 165 diabetic patients (330 eyes) aged 0-18 years, examined between January 2006 and September 2018 at the Pediatric Department of 'S. Maria della Misericordia' Udine Hospital who underwent at least one complete ophthalmologic examination at the Ophthalmology University Clinic at the Udine Hospital. OCT and OCTA data were available for 37 patients (72 eyes, 2 excluded). The associations between ocular complications and selected potential risk factors were evaluated by univariate analyses.

Results

No patient had signs of ocular diabetic complications or any macular morphological or micro-vascular impairment, regardless of any potential risk factor. The prevalence of strabismus and refractive errors in the study group, was found to be similar to non-diabetic pediatric populations.

Conclusion

Screening and follow-up of ocular diabetic complications in children and adolescents could be performed less frequently than in adults with diabetes. There is no need to screen potentially treatable visual disorders in diabetic children earlier or more frequently than in the healthy children thus reducing time spent in hospital and permitting a better tolerance to medical examinations in diabetic pediatric patients. We described the OCT and OCTA patterns in a pediatric population with DM.

Optical Coherence Tomography Angiography in Patients with Amblyopia

To determine the optical coherence tomography angiography (OCTA) parameters including foveal avascular zone (FAZ) and vessel density (VD) in the amblyopic eyes compared with the fellow sound eyes and the eyes of the non-amblyopic subjects. In this case-control study, a total of 23 eyes from unilateral amblyopic children were included as cases. The sound eye of the amblyopic children was considered as the internal control and the right eyes of the non-amblyopic children were considered as the external control. All participants underwent image recording with OCTA. In the present study, an equal number of 23 unilateral amblyopic eyes and 23 right eyes of non-amblyopic age- and sex-matched children were included as the cases and controls, respectively. The average age of participants in the case and controls were 9.86 ± 3.12 and 8.5 ± 2.35 years, respectively. Twelve patients (52.2%) in the case group and 14 subjects (60.9%) in the control group were female. Whole vascular density of the macula in superficial capillary plexuses (SCP) was significantly lower in the external controls compared with the other studied groups (P = .026). However, the VD of the deep capillary plexuses (DCP) was significantly greater in the external controls than cases and internal controls (P= .029). The average FAZ area was 0.26 ± 0.06 mm² in amblyopic eyes that was significantly higher compared with fellow eyes (0.21 ± 0.07 mm²; P= .022), but it was not different with non-amblyopic eyes (0.22 ± 0.118 mm²). Based on our findings, there were no significant difference in the cases of foveal, parafoveal, and perifoveal in both superficial and deep vascular densities among amblyopic and non-amblyopic eyes, whereas deep whole density of the amblyopic eyes showed lower percent compared to non-amblyopic ones that indicates decrease blood supply of the amblyopic eyes in this region. Additionally, FAZ was larger in amblyopic eyes than internal controls.

Analysis of Retinal Microvasculature Features in Amblyopic Eyes: A Meta-Analysis

BACKGROUND

Amblyopia is a common cause of visual disorder with several changes in retinal structure and vessel. To date, alterations in retinal microvasculature features in amblyopia have yielded inconsistent results.

OBJECTIVES

This meta-analysis aimed to evaluate retinal vessel density (VD) in amblyopic patients using optical coherence tomography angiography (OCTA).

METHODS

PubMed, Web of Science, Embase, and Cochrane Library databases were systematically searched for published articles comparing retinal microvasculature characteristics in patients with amblyopia and controls. Continuous variable outcomes were assessed using the mean difference (MD) with a 95% confidence interval. Review Manager Version 5.30 was used for the analysis.

RESULTS

Thirteen qualified articles were pooled in this meta-analysis. Compared with controls, the foveal whole en face VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP) of patients as measured by 3 × 3-mm scans were significantly lower in amblyopia eyes (MD: -1.37, p = 0.0003; MD: 1.70, p < 0.00001, respectively). Similarly, in the 6 × 6-mm scans, foveal whole en face VD of the SCP and DCP were remarkably lower in amblyopia eyes than in controls (MD: -2.24, p = 0.03; MD: -5.08, p = 0.04, respectively). The parafoveal VD of SCP in 3 × 3-mm scans (MD: -1.96, p < 0.00001) was also lower in amblyopic patients than in controls. Similarly, in 6 × 6-mm scans, amblyopia eyes showed a significant decrease and a trending decrease in the parafoveal VD of the SCP (MD: -3.85, p = 0.007) and DCP (MD: -3.03, p = 0.10), respectively. For whole radial peripapillary capillary (RPC), VD was significantly reduced in amblyopic patients compared to controls (MD = -0.83, p < 0.00001). In addition, the deep foveal avascular zone (FAZ) was larger in amblyopic eyes than in the controls (MD = 0.55, p = 0.007).

CONCLUSIONS

Our data suggest that whole foveal and parafoveal VD and RPC whole VD were reduced in patients with amblyopia. Moreover, our results reveal that the FAZ is larger in amblyopic patients. Consequently, OCTA may have the potential for diagnosing and monitoring patients with amblyopia.

Optical coherence tomographic angiography in children with anisometropic amblyopia

OBJECTIVES

To observe and compare the difference in retinal perfusion using optical coherence tomography angiography (OCTA) between anisometropic amblyopia in children and fellow eyes as well as age-matched controls.

METHODS

A total of 16 children with anisometropic amblyopia and 19 age-matched healthy subjects were enrolled. All participants underwent OCTA examination, with 3 mm × 3 mm and 6 mm × 6 mm scans in the macular region. Perfusion parameters of the superficial retinal layer were measured by built-in software, including the macular foveal avascular zone (FAZ) area, perimeter and circularity, as well as the vessel length density (VLD) and perfusion density (PD) of the foveal, parafoveal and perifoveal regions.

RESULTS

Among the 16 patients with anisometropic amblyopia, the FAZ area was significantly higher in diseased eyes (P = 0.027) than in fellow eyes. The VLD and PD of the foveal average and the VLD of the nasal quadrant of the perifoveal region in anisometropic amblyopic eyes were significantly lower than those in fellow eyes (P < 0.05). The VLD of the parafoveal average, the superior, temporal, inferior and nasal quadrants of the parafoveal region, and the nasal quadrant of the perifoveal region in anisometropic amblyopic eyes were significantly lower than those in healthy controls (P < 0.05). The PD of the parafoveal average, and the inferior quadrant of the parafoveal region in anisometropic amblyopic eyes were significantly lower than those in healthy controls (P < 0.05). The VLD of the parafoveal average, the superior, inferior and nasal quadrants of the parafoveal region, and the nasal quadrant of the perifoveal region in fellow eyes were significantly lower than those in healthy controls (P < 0.05). The PD of the parafoveal average, and the inferior quadrant of the parafoveal region in fellow eyes were significantly lower than those in healthy controls (P < 0.05).

CONCLUSIONS

The macular vessel density of the superficial capillary plexus is lower in anisometropic amblyopic children than in age-matched healthy children. Compared with the fellow eye, the perfusion of the amblyopic eye in children with anisometropic amblyopia also decreases.

Retinal vascular impairment in Wolfram syndrome: an optical coherence tomography angiography study

To evaluate differences in macular and optic disc circulation in patients affected by Wolfram Syndrome (WS) employing optical coherence tomography-angiography (OCTA) imaging. In this retrospective study, 18 eyes from 10 WS patients, 16 eyes of 8 patients affected by type I diabetes and 17 eyes from 17 healthy controls were enrolled. All patients were imaged through OCT and OCTA and vascular parameters, as perfusion density (PD) and vessel length density (VLD) were measured. OCTA showed reduced PD in WS patients at the macular superficial capillary plexus (SCP, 27.8 ± 5.3%), deep vascular complex (DVC, 33.2 ± 1.9%) and optic nerve head (ONH, 21.2 ± 9.1%) compared to both diabetic patients (SCP 33.9 ± 1.9%, P < 0.0001; DVC 33.2 ± 0.7%, P = 1.0; ONH 33.9 ± 1.3, P < 0.0001) and healthy controls (SCP 31.6 ± 2.5, P = 0.002; DVC 34.0 ± 0.7%, P = 0.089; ONH 34.6 ± 0.8%, P < 0.0001). Similarly, VLD was lower in WS patients at the SCP (10.9 ± 2.7%) and ONH levels (7.5 ± 4.1%) compared to diabetic patients (SCP 13.8 ± 1.2%, P = 0.001; DVC 13.8 ± 0.2%, P < 0.0001; ONH 13.0 ± 0.7%, P =  < 0.0001), but higher in DVC (15.7 ± 1.2%, P < 0.0001). Furthermore, VLD was lower in WS patients in all the vascular parameters compared to controls (SCP 13.8 ± 1.5%, P < 0.0001; DVC 17.3 ± 0.6%, P < 0.0001; ONH 15.7 ± 0.5%, P < 0.0001). A significant microvasculature impairment in the macular SCP and ONH microvasculature was demonstrated in eyes affected by WS. Microvascular impairment may be considered a fundamental component of the neurodegenerative changes in WS.

Analysis of Macular Retinal Thickness and Microvascular System Changes in Children with Monocular Hyperopic Anisometropia and Severe Amblyopia

OBJECTIVE

To study the changes of macular retinal thickness and microvascular system in children with monocular hyperopic anisometropia and severe amblyopia using optical coherence tomography angiography (OCTA) and to explore the value of OCTA in the diagnosis and treatment of amblyopia.

METHODS

Thirty-two children with monocular hyperopic anisometropia and severe amblyopia who were treated in the Department of Ophthalmology of the First Affiliated Hospital of Gannan Medical College from January 2020 to December 2020 were included in the study. Eyes with amblyopia (n = 32) served as the experimental group, and the contralateral healthy eyes (n = 32 eyes) served as the control group. All children underwent comprehensive ophthalmological examination including slit lamp, eye position, visual acuity, optometry, eye movement, intraocular pressure, ocular axis, and fundus examination to rule out organic lesions. Macular 6 mm × 6 mm scans were performed on both eyes of all subjects by the same experienced clinician using an OCTA instrument. After ImageJ processing, the vessel density, inner layer, and full-layer retinal thickness (RT) of superficial retinal capillary plexus (SCP) were obtained. All data were analyzed by SPSS21.0 software, and a paired t-test was used for comparison between groups. P < 0.05 was considered to indicate statistical significance.

RESULTS

The vessel densities of macular SCP in the amblyopia and control groups were 47.66 ± 2.36% and 50.37 ± 2.24% in the outer superior, 49.19 ± 2.64% and 51.44 ± 2.44% in the inner inferior, 49.63 ± 2.51% and 51.41 ± 3.03% in the outer inferior, and 45.56 ± 3.44% and 50.44 ± 3.52% in the outer temporal regions, respectively. The vessel density of macular SCP in the amblyopia group was significantly lower than that in contralateral healthy eyes in the outer superior, inner inferior, outer inferior, outer temporal, and central regions. There was no significant difference between the two groups in the inner superior, inner nasal, outer nasal, and inner temporal regions. The macular RT in the amblyopia group and the control group is 90.38 ± 6.09 μm and 87.56 ± 5.55 μm in the outer temporal, respectively. The RT in the macular inner layer in the outer temporal region of the amblyopia group was thicker than that of the control group (P < 0.05). There was no significant difference in the other eight regions between the two groups. The whole macular RT in the amblyopia group was thicker than that in the control group in nine regions, and the central area of macular RT in the amblyopia and control groups was 229.06 ± 6.70 μm and 214.50 ± 10.36 μm, respectively.

CONCLUSION

The OCTA results showed the overall RT of macula in 9 areas in the amblyopia group was thicker than that in the control group, which could show that the macular retinal thickness can be a potential way to distinguish the children with monocular hyperopic anisometropia and severe amblyopia.

Macular Microvasculature Features of the Eyes of Healthy Korean Children Using Optical Coherence Tomography Angiography

Purpose: We used optical coherence tomography angiography to analyze the macular microvasculature of normal eyes of healthy Korean children; we derived normative data stratified by age.Methods: We retrospectively analyzed the medical records of 68 children (126 eyes) aged from 3 to 15 years. Optical coherence tomography angiography was performed on 3-mm2 regions centered on the fovea. The vascular densities of the superficial and deep capillary plexuses and the foveal avascular zone were determined, and analyzed by age. We sought correlations between age, gender, axial length, and the spherical equivalent.Results: The foveal, superficial capillary plexus vessel densities were 17.41 ± 5.41, 20.53 ± 4.76, 21.78 ± 5.73, and 22.95 ± 3.91% in children aged 3-5, 6-8, 9-11, and 12-15 years, respectively. The vessel densities of the foveal deep capillary plexus were 30.20 ± 6.59, 34.54 ± 7.16, 35.81 ± 6.02, and 37.38 ± 5.16% in those aged 3-5, 6-8, 9-11, and 12-15 years, respectively. Significant differences by age were apparent (p = 0.002, p < 0.001, respectively). The foveal vessel densities of the superficial and deep capillary plexuses were positively correlated with axial length (R2 = 0.153, p < 0.001; R2 = 0.158, p < 0.001, respectively) and the foveal avascular zone area was negatively correlated with axial length (R2 = 0.085, p < 0.001).Conclusions: The vessel densities of the superficial and deep capillary plexuses measured via optical coherence tomography angiography in normal eyes of healthy Korean children differed by age, and correlated significantly with axial length.

Microvascular differences in amblyopic subgroups: An observational case-control study

PURPOSE

To determine retinal microvascular differences among amblyopic subgroups and compare them with control eyes.

STUDY DESIGN

This study was designed as an observational case-control study.

METHODS

Twenty-three strabismic, 23 anisometropic, 22 meridional, 22 ametropic amblyopic eyes, and 24 healthy control eyes were included. The mean vessel densities in the deep and superficial capillary plexus, the foveal avascular zone area, the choriocapillaris flow area, and the foveal thickness were compared.

RESULTS

Vessel density was markedly lower in all sectors of the amblyopic subgroups in the deep capillary plexus than in control eyes. Density was significantly lower in the superficial capillary plexus only in ametropic and meridional amblyopic eyes. Among these groups, the meridional amblyopic eyes had the largest choriocapillaris flow area (p = 0.013) and the lowest vessel density in all sectors (p < 0.001). The foveal avascular zone area was similar in all groups (p = 0.561). The fovea was significantly thicker only in the anisometropic and meridional subgroups than control eyes (p = 0.011, p = 0.001, respectively). The foveal avascular zone area was inversely related to the foveal thickness in all groups.

CONCLUSION

Retinal structural and microvascular differences were found among amblyopic subgroups. Optical coherence tomography angiography can noninvasively detect these variations, which may be related to the etiologic factors.

Macular perfusion normative data acquired with optical coherence tomography angiography in healthy four-year-old Caucasian children

BACKGROUND

The purpose of this cross-sectional study involving healthy emmetropic four-year-old Caucasian children was to provide a macular perfusion normative database acquired with optical coherence tomography angiography (OCTA). One eye of each examinee underwent OCTA imaging. The following parameters were analyzed using AngioTool Image J software: vessels area (VA), vessels density (VD), total number of junctions (TNJ), junctions density (JD), total vessel length (TVL), average vessel length (AVL), total number of endpoints (TNEP), lacunarity (L), vessel diameter index (VDI), tortuosity (T) and foveal avascular zone (FAZ). Average central macular thickness (CMT) and average central macular volume (CMV) were measured.

RESULT

Sixty-two eyes of 62 children of average age 50.4 ± 3.8 months were examined. VA, VD, and T increased from the inner towards the outer layers of the retina. The intermediate capillary plexus had the highest JD and TNEP and narrowest FAZ. Retinal sexual differentiation was supported with higher values of the retinal VA, VDI and TNEP, and chorioretinal VA, VDI and L in males. The choriocapillaris presented with the highest VD, AVL, and T and the lowest L and TNEP.

CONCLUSION

The study provides the first detailed normative database of the macular vascular network in the youngest uniform cohort of emmetropic four-year-old children.

Quantification of macular perfusion in healthy children using optical coherence tomography angiography

Background

This study aimed at defining the variance of vessel density (VD) characteristics in the macula of children with normal eyes.

Methods

This was a cross-sectional study in which subjects with normal eyes aged 3–18 years were enrolled. The macula was scanned by optical coherence tomography angiography (OCTA). Four age groups as under 7 years, 7–10 years, 11–14 years and more than 14 years of age were defined. The influences of age, gender, and body mass index on VD were analyzed.

Results

A total of 108 normal eyes from 54 participants with a mean age of 10.9 years were enrolled in the study. At the superficial and deep retina capillary plexus (SCP and DCP) and choriocapillaris (CC), respectively, the mean VD of the fovea was 20.10%, 36.99%, and 75.67%; at parafovea, these measurements were 53.12%, 55.81%, and 69.76%; and at perifovea, these measures were 51.38%, 52.46%, and 73.47%. The median foveal avascular zone (FAZ) was 0.30 mm². No significant differences between superior-hemi VD and inferior-hemi VD were found in the studied plexuses. The VD at parafovea and perifovea CC differed significantly between groups. There was no variation in VD of macular retina and CC between eyes or sex. FAZ areas were different between genders.

Conclusions

No difference between eyes and genders in the retina and CC VD of macular area was noted. FAZ area was larger in male. Even though this is not a longitudinal study, it may provide us with hints about macular vascular development during puberty and clinical implications of OCTA in children.

OCT-Angiography Findings in Patients with Amblyopia: Comparison between Healthy Controls, Treatment-Responsive, and Treatment-Unresponsive Amblyopic Patients

There is no consensus on whether amblyopia affects the retinal vascular plexus and morphology. Previous studies focused on the differences between amblyopic patients and normal controls without evaluating amblyopic eyes after patching. To evaluate differences in the superficial vascular density of amblyopic eyes, normal eyes, and amblyopic eyes reaching normal BCVA after patch therapy, OCTA was used. All patients underwent a comprehensive ophthalmological examination, including visual acuity, refraction, ocular motility tests, and anterior and posterior segment examination. OCTA was performed by an expert physician using the Zeiss Cirrus 5000-HD-OCT Angioplex (Carl Zeiss, Meditec, Inc., Dublin, OH, USA). OCTA scans were performed using a 3 × 3 mm² and 6 × 6 mm² fovea-centered image setting. The mean outer macular vessel density in the previously amblyopic group was 19.15 ± 0.51%. This was statistically significantly higher than in both the amblyopic group (18.70 ± 1.14%) and the normal controls (18.18 ± 1.40%) (p = 0.014). The previously amblyopic group also significantly differed from both normal controls and amblyopic eyes with regards to the inner (p = 0.011), outer (p = 0.006), and full (p = 0.003) macular perfusion. Finally, linear regression analysis revealed that BCVA was linearly correlated to outer perfusion in amblyopic (p = 0.003) and ex amblyopic eyes (p < 0.001). Considering the cross-sectional nature of our study, from our results, we can only hypothesize a possible correlation between light stimulation and retinal vasculature development. However, further longitudinal studies are needed to support this hypothesis.

Optical coherence tomography angiography in amblyopia: A critical update on current understandings and future perspectives

Optical coherence tomography angiography (OCTA) is a non-invasive tool to assess the retino-choroidal vasculature in vivo. It tracks the red blood cell movement and maps the vasculature in quick succession. In routine, diabetic retinopathy, age related macular degeneration, central serous chorioretinopathy, and others are commonly being studied to unveil its clinic role. On the other hand, amblyopia is a condition where the visual acuity is subnormal due to non-organic causes in the eye. But the OCTA studies till now have shown variable changes along retino-choroidal vasculature. Hence, to comprehend the existing literature knowledge, a systematic literature search was carried out and the original works describing novel findings in amblyopic eyes on OCTA were included. Upon detailed assessment, firstly, the disturbed vasculature along superficial retinal plexus, deeper retinal plexus, and choroidal plexus were evident in most untreated amblyopic eyes. However, such changes were not uniform, which is due to noted heterogenic patient profile, small sample size, biometric biases, non-uniform algorithms, and other factors. And to note, even in presence of such diverse changes, almost all the authors stated a plausible explanation for their notable changes. Secondly, the utility of OCTA in identifying vascular changes with standard treatments and segregation of visual beneficiaries from non-beneficiaries were possible. Hence, to conclude, OCTA is a valuable tool which can provide valuable useful insights into the amblyopic eyes during pre and post treatment periods. However, to gather more concrete evidence for clinical benefits, systematic, homogenous, and better structured clinical studies are mandated.

Evaluation of the Optic Disc and Macula in Healthy Children Using Optical Coherence Tomography Angiography

Objectives

To perform the measurements of the optic disc and macula in healthy children using optical coherence tomography angiography (OCTA) in order to determine the normative data values and compare these by age, gender, spherical equivalent (SE), and axial length (AL).

Materials and Methods

A total of 146 eyes belonging to 146 healthy children (74 girls, 72 boys) aged 6 to 16 years were included in this prospective study. Refraction and biometry measurements were performed. Retinal nerve fiber layer thickness (RNFLT), central macular volume, and central macular thickness (CMT) were measured by optical coherence tomography (OCT) after dilatation. Using the OCTA device, foveal avascular zone (FAZ) area, vascular density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) of the macula, and the VD of the radial peripapillary capillary plexus (RPCP) of the optic disc were recorded.

Results

The mean age of the study group was 11.27±3 years, the mean AL was 23.39±1.18 mm and the mean SE was -1.31±1.61 diopters. The mean FAZ area was 0.3±0.09 mm2, the mean SCP-VD was 43.88±3.4%, the mean DCP-VD was 39.6±3.55%, and the mean RPCP-VD was 52.47±3.42%. When the relationship between the OCTA measurements and the SE and AL values were analyzed, there was no statistical significance (p>0.05). When age and OCTA measurements were compared, only DCP-VD values were found to significantly decrease with increasing age (p=0.015). There was no significant difference in OCTA measurements based on gender (p>0.05). Similarly, no statistical age-based differences were observed in RNFLT, CMV and CMT values (p>0.05).

Conclusion

With its short procedure time and no dye requirement, OCTA can be safely used in the evaluation of the optic disc and macular perfusion in children. Determination of normative values in children will be useful in detecting pathologic changes in tissue in patients with retinal diseases.

Evaluation of macular and optic nerve head parameters in amblyopic eyes: An optical coherence tomography study

PURPOSE

To evaluate morphological differences in retinal nerve fibers layers (RNFL), optic nerve head (ONH), ganglion cell complex (GCC), and macular thickness between amblyopic and normal eyes from spectral domain optical coherence tomography (SD-OCT).

METHODS

Of 234 eyes of 117 children, four groups emerged: group A (162 eyes of 81 non-amblyopic subjects); group B (32 fellow eyes of 32 subjects with monolateral amblyopia); group C (32 amblyopic eyes of 32 subjects affected by monolateral amblyopia); group D (8 amblyopic eyes of 4 subjects with bilateral amblyopia). Patients underwent SD-OCT for ONH parameters, RNFL, GCC and macular thickness, retina map, and ONH scan quality index (SQI). Two-sided p values <0.05 were taken as statistically significant. (Analysis: STATA v.13).

RESULTS

Parameters with a significant difference between groups (p < 0.005) with their Standard Deviation (SD) are presented: rim area, 2.08 (0.49) mm² in group A and 1.76 (0.68) mm² in group C; disk area, 2.43 (0.45) mm² in group A and 2.02 (0.71) mm² in group C; central macular thickness, 250.99 (19.74) µm in group A and 267.16 (23.52) µm in group C; nerve fiber ONH SQI, 62.82 (13.15) in group A, 51.26 (15.55) in group C, 48.29 (14.37) in group D; retina map SQI, 63.34 (10.34) in group A and 57.34 (9.84) in group C. For other parameters no significant difference was observed (p > 0.005).

CONCLUSIONS

Amblyopia may influence optic nerve morphology, central macular thickness, and OCT scan quality. RNFL and GCC are not affected by monolateral amblyopia.

Macular perfusion density evaluation in constant and intermittent exotropia by means of optical coherence tomography angiography

Background

To quantify and compare retinal microvascular features using optical coherence tomography angiography (OCTA) in constant (XT) and intermittent exotropia (IXT).

Methods

An observational cross-sectional study was conducted from September 2020 to November 2020 at the Affiliated Eye Hospital of Wenzhou Medical University. OCTA examination was performed to evaluate the macular perfusion density of the deep capillary plexus (DCP), superficial capillary plexus (SCP), and foveal avascular zone (FAZ) parameters in XT and IXT patients, and in age-matched controls. The study parameters were analyzed.

Results

A total of 76 participants, including 16 (21%) XT patients, 24 (32%) IXT patients, and 36 (47%) controls, were recruited. The exodeviation angle was 39.06 ± 10.38 prism degrees (PD) at near and 43.00 ± 9.74 PD at distance in the XT group, and 27.13 ± 18.28 PD at near and 31.04 ± 18.82 PD at distance in the IXT group. The macular perfusion density of the DCP in 6 × 6-mm scans and the SCP in 3 × 3-mm scans were lower in the deviating eyes than in the fixating eyes of XT patients (p < 0.001, p = 0.032, respectively). The macular perfusion density of the DCP in the deviating eyes of XT and IXT patients was significantly lower than that of the controls. There was no significant difference in the FAZ parameters among the groups.

Conclusions

In XT patients, OCTA revealed lower macular perfusion density in deviating eyes than in fixating eyes and control eyes. IXT patients showed no difference between the two eyes, but the macular perfusion density of the DCP was lower than that of the controls.

Evaluation of amblyopic eyes with optical coherence tomography angiography and electrophysiological tests

Purpose

To investigate the structural and functional changes of the retina and optic nerve in amblyopia.

Methods

Eighteen patients with unilateral anisometropic amblyopia and 27 age-matched healthy controls were involved in this study. All patients underwent optical coherence tomography angiography (OCTA), pattern visual evoked potential (pVEP), and flash electroretinogram (fERG).

Results

There was no statistically significant difference in terms of the foveal avascular zone (FAZ), perifoveal superficial density, whole superficial density, parafoveal deep density, perifoveal deep density among the eyes (P > 0 0.05). Significant differences were found only in superficial capillary plexus (SCP) vessel density in whole (P = 0.029) and parafoveal (P = 0.008) image. In electrophysiological tests, while VEP latencies of the amblyopic eyes increased compared to nonamblyopic eyes and controls (P = 0.027), VEP amplitudes decreased in amblyopic and nonamblyopic eyes compared to controls (P = 0.01), amplitudes of the rod (P = 0.027) and cones (P < 0.001) also decreased in amblyopic eyes compared to nonamblyopic and healthy eyes. When we assessed the correlation between the parameters of OCTA and electrophysiological test, only a significant correlation was found between parafoveal SCP vessel density and VEP amplitudes (r = 0.341).

Conclusion

We found a significant decrease only in SCP vessel density of the OCTA parameters in amblyopic eyes compared to healthy eyes. We detected a significant relationship between parafoveal SCP vessel density and VEP parameters, which might be associated with the underlying pathophysiology of the amblyopia.

Macular Microvasculature and Associated Retinal Layer Thickness in Pediatric Amblyopia: Magnification-Corrected Analyses

Purpose

The purpose of this study was to characterize macular microvasculature and structural retinal layers using magnification-corrected optical coherence tomography angiography (OCTA) images in children with amblyopia.

Methods

This prospective cross-sectional study included 22 children with unilateral amblyopia (4–11 years of age) receiving spectral-domain OCTA. Vessel densities in foveal and parafoveal regions of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were measured in amblyopic and fellow eyes using a customized image analysis program correcting the scale of retinal image with axial length. Iowa Reference Algorithms (Iowa Institute for Biomedical Imaging) were used to measure mean thickness values of 10 intra-retinal layers rescaled for image size correction.

Results

Foveal and parafoveal vessel densities in amblyopic eyes were lower than that of the fellow eyes in the SCP (fovea: P = 0.006 and parafovea: P = 0.003) and the DCP (P = 0.024 and P = 0.025, respectively). Amblyopic eyes had significantly smaller foveal avascular zone (FAZ) area than fellow eyes (P < 0.001). There were significant differences in retinal layer thickness between paired eyes, particularly in the inner retina in both foveal and parafoveal regions; retinal nerve fiber layer (RNFL) (P = 0.024 and P = 0.095, respectively), ganglion cell layer (P < 0.001 and P = 0.008), inner plexiform layer (IPL; P = 0.12 and P = 0.037), inner nuclear layer (P = 0.005 and P = 0.005), and outer plexiform layer (OPL; P = 0.02 and P = 0.057), except in the foveal IPL, the parafoveal RNFL, and OPL.

Conclusions

Unilateral amblyopic eyes demonstrate reduced macular vessel density and thicker inner retinal layers compared with fellow eyes even after correcting for image magnification. Changes in macular microvasculature and structural layers may offer valuable insights in the development of amblyopia.

Association of Optical Coherence Tomography Angiography Metrics With Detection of Impaired Macular Microvasculature and Decreased Vision in Amblyopic Eyes: The Hong Kong Children Eye Study

Importance

Microvascular abnormalities in amblyopia are becoming evident with high-resolution imaging, such as optical coherence tomography angiography (OCT-A); however, to our knowledge, the clinical significance and use of these findings are unknown.

Objective

To assess changes in quantitative OCT-A metrics in amblyopic eyes and explore their association with visual acuity in children.

Design, Setting, and Participants

This population-based nested case-control study included children aged 6 to 8 years who were consecutively recruited between January 2016 and July 2017 from the population-based Hong Kong Children Eye Study (HKCES) at the Chinese University of Hong Kong Eye Centre. All participants underwent OCT-A with a swept-source OCT and detailed ophthalmic investigations. Macular microvasculature of the superficial capillary plexus was quantified by a customized automated image analysis program. A multivariable linear regression was conducted to evaluate the differences in OCT-A metrics between amblyopic and nonamblyopic eyes after adjustment for all known confounders. Data analysis was conducted from September to November 2018.

Main Outcomes and Measures

Differences in OCT-A metric (foveal avascular zone [FAZ]) area, FAZ circularity, vessel density, vessel diameter index, and fractal dimension between amblyopic and nonamblyopic eyes.

Results

There were 30 participants with amblyopia (mean [SD] age, 7.57 [1.2] years; 16 girls [53.3%]) and 1045 controls (mean [SD] age, 7.65 [1.0] years; 580 girls [55.5%]) in this cohort. Compared with control eyes, amblyopic eyes had decreased FAZ circularity (-0.058; 95% CI, -0.096 to -0.021, P = .002), decreased fractal dimension (-0.014; 95% CI, -0.024 to -0.003; P = .01), and increased vessel diameter index (0.002; 95% CI, 0.002 to 0.003; P < .001). A difference was not identified between FAZ area and vessel density. LogMAR visual acuity was associated with FAZ circularity (sβ, -0.133; P < .001) and vessel diameter index (sβ, 0.097; P = .001) but not with vessel density nor FAZ area.

Conclusions and Relevance

The results of this population-based study in children supports the presence of macular microvascular abnormalities in amblyopic eyes. Such changes as measured by OCT-A metrics are associated with visual acuity, inferring retinal involvement in the development of amblyopia and suggesting a potential role of quantitative OCT-A metrics in the diagnosis and recognition of amblyopia.

Effect of amblyopia treatment on macular microvasculature in children with anisometropic amblyopia using optical coherence tomographic angiography

To measure the retinal microvascular density in patients with anisometropic amblyopia using optical coherence tomographic angiography (OCTA) and to evaluate the effects of successful amblyopia treatment on microvasculature in retina. 59 children (5–12 years old) including 22 newly diagnosed unilateral anisometropic amblyopia, 16 recovered unilateral anisometropic amblyopia, and 21 control children were imaged with OCTA using 6 × 6-mm macular scan pattern. Vessel densities of the superficial capillary plexus (SCP), the deep capillary plexus (DCP), and the overall macular thickness were acquired and compared among the three groups. After adjustment for axial length, the amblyopia group showed lower macular vessel density in the SCP (P = 0.005) and in the DCP (P = 0.004) compared with that of the control group. However, for the recovered amblyopia group, no difference of vessel density was found when compared with the control group in both the SCP (P = 0.548) and the DCP (P = 0.124). No difference of the mean macular thickness was found among three groups (P ≥ 0.15). Children with anisometropic amblyopia have reduced macular vessel density in OCTA, while no difference of macular vessel density was found between the recovered amblyopic and control eyes. Macular thickness showed no difference in anisometropic amblyopia and remained unchanged after amblyopic treatment.

Macular Microvasculature Density Changes in Anisometropic Amblyopic Eyes after Successful Treatment

Purpose. To determine if the abnormal macular microvasculature in hyperopic anisometropic amblyopia changes after occlusion therapy, and to discover if the macular microvasculature influences the efficacy of amblyopic treatment. Materials and Methods. Twenty-two children with hyperopic anisometropic amblyopia (median, 8 years old) were enrolled along with 66 healthy controls of similar age and gender distribution. Best-corrected visual acuity (BCVA) was determined, and macular vessel density in the superficial and deep capillary plexuses (SCPs and DCPs, respectively) was measured by optical coherence tomography angiography before and after refractive correction and occlusion therapy. Changes in BCVA and macular SCP and DCP vessel density were measured after amblyopia treatment of 7.5 ± 4.4 months. Results. The amblyopic baseline BCVA, logMAR 0.42 ± 0.27, improved to logMAR 0.18 ± 0.18 in 14 patients (64%) after amblyopia treatment ( $P<0.001$ ). In 8 patients (36%), there was no improvement in the BCVA. In amblyopic eyes with improved BCVA, the SCP density tended to increase in each parafoveal quadrant, while it tended to decrease in all quadrants of the fellow eyes. For patients in whom BCVA did not improve, the macular SCP vessel density tended to decrease in all quadrants of the amblyopic and fellow eyes. The posttreatment difference in SCP vessel density between amblyopic and fellow eyes was not significant. Multiple linear regression analysis showed that older age and greater foveal SCP vessel density were negatively correlated with BCVA improvement ( $P<0.018$ and $P<0.036$ , respectively). Conclusions. Macular vessel density tends to increase in anisometropic amblyopic eyes after successful treatment. Younger age and lower SCP macular density are predictive of a greater therapeutic effect of occlusion therapy.

Macular capillary system and ganglion cell-layer complex of the amblyopic eye with optical cohorence tomography angiography and optical cohorence tomography

PURPOSE

To investigate the macular capillary system and ganglion cell-layer complex of the amblyopic eye with OCTA and OCT in comparison with fellow non-amblyopic eyes and a healthy control group and to examine their relationship with the severity of amblyopia.

METHODS

This prospective, cross-sectional comparative study enrolled 25 amblyopic patients and 25 healthy controls. All patients and controls underwent OCTA and OCT imagining. Macular vessel densities of the Superficial Capillary Plexus (SCP) and Deep Capillary Plexus (DCP) and retinal thickness were measured by OCTA and ganglion cell layer (GCL) by OCT.

RESULTS

SCP density at the fovea and parafovea was significantly lower in amblyopic eyes than in fellow eyes and control group. DCP density at the fovea was significantly lower in amblyopic eyes than fellow eyes and control group. Mean GCL thickness on OCT was 0.73 ± 0.07 μm in amblyopic eyes, 0.75 ± 0.06 μm in fellow eyes and 0.77 ± 0.06 μm in the control group. GCL volume was significantly lower in amblyopic eyes than the fellow eyes. The SCP and DCP and GCL thickness were not affected by the severity of amblyopia.

CONCLUSION

Macular vessel densities of the SCP and DCP of eyes with amblyopia is lower compared to the fellow non-amblyopic eyes and the control group. The thickness of GCL was lower in amblyopic eyes than fellow eyes while the severity of amblyopia did not have any impact on these structures. Microvascular retinal structures may have been affected in the course of amblyopia development.

Quantification of diabetic macular ischemia using novel three-dimensional optical coherence tomography angiography metrics

We applied three-dimensional (3D) analysis to optical coherence tomography angiography (OCTA) to measure macular ischemia in eyes affected by non-proliferative diabetic retinopathy (DR). A previously validated algorithm was applied to OCTA data in order to obtain 3D visualization of the retinal vasculature. Successively, a global thresholding algorithm was applied and two novel quantitative metrics were introduced: 3D vascular volume and 3D perfusion density. Two-dimensional (2D) OCTA metrics were also obtained with different binarization thresholds for comparison. Of the 30 patients included, 15 were diagnosed with DR and 15 were controls. The 3D vascular volume and 3D perfusion density were reduced in DR eyes (P < .0001). The 2D variables also significantly differ between groups. The 3D perfusion density had the highest area under the receiver operating characteristic curve (0.964) among tested variables. Assessing quantitative perfusion using 3D analysis is reliable and promising, and with an elevated diagnostic efficacy in identifying DR eyes.

MACULAR MICROVASCULAR NETWORKS IN HEALTHY PEDIATRIC SUBJECTS

PURPOSE

To report optical coherence tomography angiography (OCTA) values in healthy pediatric eyes and to identify factors that may modify these values.

METHODS

In this prospective observational cross-sectional study, macular OCTA images were acquired from healthy pediatric patients. Main outcome measures were 1) foveal avascular zone (FAZ) area at the level of the superficial retinal capillary plexus (SCP); 2) SCP and deep retinal capillary plexus (DCP) perfusion density (based on the area of vessels); 3) SCP and DCP vessel density (based on a map with vessels of 1-pixel width); and 4) CC perfusion density. Multiple regression analysis was performed to assess the effect of age, sex, ethnicity, refraction, and foveal macular thickness (FMT) on OCTA parameters.

RESULTS

Seventy-seven eyes from 52 subjects (23 male and 29 female) were included in analysis. Mean age was 11.1 ± 3.3 years (range = 5.0-17.0 years). Twenty-nine (55.8%) subjects were white, 14 (27.0%) Hispanic, 8 (15.4%) Asian, and 1 (1.8%) African-American. Mean refraction was -0.1 ± 2.4 diopters (D) (range = -5.75 to +9.0 D). Mean FMT was 248.6 ± 18.6 μm. Larger FAZ area was significantly associated with older age (P = 0.014). Furthermore, larger FAZ area was associated with reduced FMT (P < 0.0001). Male sex was associated only with increased SCP perfusion density (P = 0.042). Increased CC perfusion density was associated with younger age (P = 0.022).

CONCLUSION

We report data for pediatric OCTA parameters in healthy subjects. Several variables influence the density of macular microvascular networks, and these factors should be considered in the OCTA study of pediatric eye disorders.

Comparison of Pre-Treatment vs. Post-Treatment Retinal Vessel Density in Children with Amblyopia

BACKGROUND

Prior studies have reported a lower retinal vessel density (RVD) in amblyopic vs. non-amblyopic eyes. No studies have shown if amblyopic eye RVD changes following patching therapy. We assessed for RVD differences between pre-treatment vs. post-treatment amblyopic eyes.

METHODS

Participants were included if they were <10 years old with unilateral amblyopia. All subjects were required to visit the pediatric eye clinic for examination. Exclusion criteria included: deprivation amblyopia, bilateral amblyopia, nystagmus, media opacity, intraocular inflammation, or any retinal disease. All participants underwent optical coherence tomography angiography (OCTA) before and after refraction and patching treatment. Outcomes included superficial (SCP) and deep (DCP) capillary plexus RVD.

RESULTS

12 patients (12 amblyopic eyes) were included. Mean (SD) age, gestational age (GA), birth weight (BW), and follow-up time were: 6.5 (1.7) years, 39.4 weeks (1.4 w), 3271 g (262 g), and 114 days (46d), respectively. There was a significant increase in the RVD of the DCP in 3 × 3-mm scans after treatment, specifically in the whole image (52.6 ± 5.75 vs 56.5 ± 2.48%, p = .046) and superior hemisphere regions (52.47 ± 6.17 vs 56.73 ± 2.27%, p = .048).

CONCLUSIONS

Amblyopic eye RVD potentially increases after amblyopia treatment in specific regions of the retina. Further research is required to refine this clinical parameter.

Inter-Ocular Symmetry of Vascular Density and Retinal Thickness in Unilateral Anisometropic Amblyopia

Background

Inter-ocular symmetry of macular vascular anatomy in healthy subjects has been well documented in previous optical coherence tomography angiography (OCTA) studies. In our present study, we have demonstrated that the presence of anisometropic amblyopia in one eye does not alter this unique feature significantly. We investigated whether the presence of unilateral anisometropic amblyopia due to moderate amounts of hyperopia and/or astigmatism would have any significant influence on measurements of retinal thickness (RT) and superficial vessel density (SVD) in adult subjects.

Subjects and methods

In the study group, both eyes of 21 adult subjects with unilateral anisometropic amblyopia were enrolled. Only one eye of an age-matched control group including 33 subjects was randomly selected. RT and SVD were measured in foveal and parafoveal retinal areas and compared in amblyopic eyes, their fellow eyes and in the control group. Inter-ocular symmetry of RT and SVD in amblyopic and fellow eyes were investigated by using correlation analysis.

Results

There were statistically significant inter-ocular correlations of foveal and parafoveal RT in amblyopic and fellow eyes (P < 0.0001, for both). Foveal and parafoveal RT of the control group were not statistically different from amblyopic eyes (P = 0.072 and P = 0.46, respectively). There was no difference between foveal SVD of amblyopic eyes and control group (P = 0.10) and a significant inter-ocular correlation was found between amblyopic and fellow eyes (P = 0.029).

Conclusion

For our adult subjects, none of the investigated OCTA parameters of the amblyopic eyes were found to be statistically different from those of age-matched controls. The preservation of inter-ocular symmetry in the amblyopic and fellow eyes implies that the influence of anisometropic amblyopia in one eye would be relatively small and negligible on routine OCTA examination.

Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age

In this cross-sectional study, we examined age-related changes in the retinal vessels of 100 healthy participants, aged from 5 to 80 years, and divided into four groups (G1, under 20 years of age; G2, from 20 to 39 years of age; G3, from 40 to 59 years of age; G4, age 60 years or older). All subjects underwent swept-source optical coherence tomography (SS-OCT) and OCT angiography (OCTA). The vascular density (VD) of the superficial (SCP) and deep capillary plexus (DCP), and choriocapillaris (CCP) were measured using OCTA. The vascular density of each capillary layer, foveal avascular zone (FAZ) area, ganglion cell-inner plexiform layer (GC-IPL) thickness, retinal thickness (RT), and choroidal thickness (CT) were compared between age groups. Most OCT variables were correlated with OCTA variables. The FAZ area; VD of the SCP, DCP, and CCP; GC-IPL thickness; RT; and CT showed significant difference (p < 0.001) between G1 + G2 and G3 + G4, except for central GC-IPL thickness (p = 0.14) and central RT (p = 0.25). Density of the retinal capillary vasculature reduced and FAZ area increased after age 40, which represents the onset of middle age.

Quantitative analysis of macular and peripapillary microvasculature in adults with anisometropic amblyopia

INTRODUCTION

The aim of this study was to compare the macular and peripapillary capillary vessel density (CVD) and foveal avascular zone (FAZ) in amblyopic eyes of adults with their fellow eyes and with eyes of healthy controls using optical coherence tomography-angiography (OCT-A).

METHODS

A total of 34 eyes of 17 patients with anisometropic amblyopia and 80 eyes of 40 age- and gender-matched healthy controls were included. CVD in superficial (SCP) and deep retinal capillary plexuses (DCP), peripapillary region, and FAZ were analyzed by OCT-A.

RESULTS

The median ages were 31 years (range 20-64) in patients with amblyopia and 34.5 years (range 24-65) in healthy controls (p = 0.242). The mean FAZ area measured was 0.329 ± 0.024 mm² in amblyopic eyes, 0.332 ± 0.025 mm² in fellow eyes, and 0.269 ± 0.015 mm² in control eyes (p < 0.05). The amblyopic eye of participants showed a decrease in CVD of SCP and DCP (p < 0.001, for all). The inside optic disk CVD measurements were lower in the amblyopic eyes than in the fellow eyes (p = 0.001) and healthy subjects (p = 0.015).

CONCLUSION

Significant differences in macular and peripapillary microvasculature were found in anisometropic amblyopic patients. The clinical significance of the results requires further investigation.

Foveal avascular zone and vessel density in children with attention deficit hyperactivity disorder

PURPOSE

To compare the retinal and choroidal microvasculature quantitatively via optical coherence angiography (OCTA) in children with attention deficit hyperactivity disorder (ADHD) who were under methylphenidate (MFD) treatment or newly diagnosed as ADHD and were not taking any medication.

METHODS

This was a cross-sectional, comparative, and observational study. The children who were between 6 and 17 years old and previously diagnosed as ADHD and were under MFD treatment or who were newly diagnosed as ADHD were included in the study. Optical coherence tomography angiography imaging was performed via OCT RT XR Avanti with AngioVue software (Optivue Inc, Freemont, CA). The main outcome measure of the study was OCTA parameters of the children with ADHD.

RESULTS

A total of 186 eyes of 186 patients were included in the study. There were 80 eyes in the control group (newly diagnosed) and 106 eyes in the treatment group (under MFD treatment). The mean duration of methylphenidate use in the treatment group was 33.9 ± 20.1 months (between 6 and 84 months). The choriocapillary flow area (p = 0.03), superficial parafoveal thickness (p = 0.01), and deep parafoveal thickness (p = 0.01) were statistically greater in the treatment group than the control group.

CONCLUSION

Most of the important OCTA parameters especially foveal avascular zone (FAZ) area and FAZ perimeter were similar in the two groups. There was a significant difference between the two groups in parafoveal thickness values which might point to a slight effect of MFD on retinal circulation.

Comparison of Retinal Vascular Structure in Eyes With and Without Amblyopia by Optical Coherence Tomography Angiography

PURPOSE

To evaluate the retinal vascular structure in amblyopic eyes by optical coherence tomography angiography (OCTA).

METHODS

Thirty-seven eyes of 37 patients with anisometric amblyopia were compared with 37 eyes of 37 age- and gender-matched control subjects by OCTA in terms of superficial capillary plexus vessel density, deep capillary plexus vessel density, and foveal avascular zone.

RESULTS

The mean age was 12 ± 4.2 years in patients with amblyopia and 13 ± 6.1 years in individuals without amblyopia. Foveal superficial capillary plexus vessel densities were 20.49% ± 3.27%, 19.70% ± 3.82%, and 19.96% ± 3.84%, and parafoveal superficial capillary plexus vessel densities were 48.50% ± 3.64%, 49.01% ± 3.33%, and 48.9% ± 2.98% in amblyopic, fellow, and control eyes, respectively. The foveal deep capillary plexus vessel densities were 18.95% ± 3.76%, 18.6% ± 4.50%, and 19.29% ± 4.01%, and parafoveal deep capillary plexus vessel densities were 51.0% ± 4.21%, 51.85% ± 4.12%, and 52.03% ± 3.57% in amblyopic, fellow, and control eyes, respectively. Superficial and deep capillary plexus vessel densities in the foveal and parafoveal areas were not significantly different between the groups (P > .05). The parafoveal area was evaluated in quadrants. In the superior quadrant, superficial and deep capillary plexus parafoveal densities were significantly lower in amblyopic eyes (P < .05). No significant difference was observed in the foveal avascular zone between the groups (P > .05).

CONCLUSIONS

Although no significant vascular damage was demonstrated by OCTA in amblyopic eyes, localized defects may be specific for it. Additional studies are needed to evaluate any specific localization of vascular damage related to amblyopia. [J Pediatr Ophthalmol Strabismus. 2020;57(1):48-53.].

Optical coherence tomography angiography-derived flow density: a review of the influencing factors

Research interest in the possibility of quantifying macular and optic nerve head perfusion through optical coherence tomography angiography (OCTA) is rapidly advancing. Numerous scientific trials have furthered our understanding of the capabilities and the limitations of this novel technology, while applying OCTA to various ocular pathologies. In recent years, different parameters such as age, gender, intraocular pressure, spherical equivalent, physical activity, systemic diseases, and medication have been shown to have a significant impact on quantitative OCTA metrics. Since OCTA is likely to remain a "hot topic" in the near future, it is crucial to be aware of influencing factors in order to ensure correct interpretation of imaging results. This article reviews the factors currently known to influence flow density (FD) as measured by OCTA in healthy eyes.

Foveal avascular zone and macular vessel density after correction for magnification error in unilateral amblyopia using optical coherence tomography angiography

Background

To investigate the area of foveal avascular zone (FAZ) and macular vessel density (VD) after correction for magnification error in unilateral amblyopia using optical coherence tomography angiography (OCTA).

Methods

Participants comprised 15 patients with unilateral amblyopia due to anisometropia with or without strabismus (mean age, 9.8 ± 3.4 years; range, 6–17 years). OCTA images were obtained by using spectral-domain OCT with angiography software. The OCTA scanning protocol used was 3 × 3-mm volume scan centered on the fovea. OCTA images were corrected for magnification errors using individual axial length (AL), and an adjusted 2.3 × 2.3-mm square was derived as a region of interest. The FAZ area and VD in both superficial capillary plexus (SCP) and deep capillary plexus (DCP) layers, foveal minimum thickness (FMT) were assessed using built-in OCTA software and ImageJ software (NIH, Bethesda, MD).

Results

LogMAR in the amblyopic eyes was significantly poorer than that of the fellow eye (p < 0.001). AL was significantly shorter in the amblyopic eye than in the fellow eye (p < 0.001). FAZ area of SCP in amblyopic eyes was significantly smaller than that of fellow eyes (p < 0.001). No significant differences were seen in FAZ area of DCP, VD of SCP, VD of DCP, and FMT between amblyopic and fellow eyes (p = 0.07, 0.43, 0.55, and 0.25, respectively).

Conclusions

Our present study after magnification error correction found smaller FAZ area of SCP in the amblyopic eye compared with the fellow eyes, but there was no significant difference in the macular VD between the amblyopic and fellow eyes.

Analysis of Macular Vessel Density and Foveal Avascular Zone in Adults with Amblyopia

Purpose: To quantify and compare the foveal avascular zone (FAZ) and the whole, parafoveal and foveal vessel density of superficial (SCP) and deep capillary plexus (DCP) in amblyopic eyes of adults and age-matched controls.Methods: This cross-sectional study involved 52 eyes from 34 subjects aged 18 to 45 years. Optical coherence tomography angiography (OCTA) was performed to all participants and SCP, DCP and FAZ were evaluated. SPSS (Statistical Package for the Social Sciences) 23 was used for data analysis.Results: Eighteen of 34 subjects (52,9%) were amblyopic and 16 (47,1%) of them controlled. Mean subject age was 31.2 years in the amblyopia group and 28.3 years in the control group. The mean FAZ measurements were 0.28 ± 0.08 in amblyopic eyes, 0.29 ± 0.08 in fellow eyes and 0.3 ± 0.11 in control eyes. The whole, foveal and parafoveal vessel density of SCP in both 3x3-mm and 6x6-mm scans were not statistically different in amblyopic eyes, fellow eyes and control eyes. In 6x6-mm scans, the whole, and parafoveal vessel density of DCP were significantly lower in amblyopic eyes than controls. There was no statistically significant difference in 3x3-mm scans about DCP.Conclusion: OCTA revealed lower vessel density in DCP of amblyopic eyes than fellow eyes and controls in adults.

Imaging Amblyopia: Insights from Optical Coherence Tomography (OCT)

Amblyopia refers to visual impairment resulting from perturbations in visual experience during visual development, typically secondary to strabismus, uncorrected refractive error, and/or deprivation. Amblyopia has traditionally been considered a cortical disease, but the depth of our understanding of this complex neurodevelopmental condition is limited by our ability to appreciate structural pathophysiology in the visual pathway. Recent advances in Optical Coherence Tomography (OCT) have facilitated numerous studies of the structural changes in the retina and optic nerve, thereby expanding our appreciation for the pathogenesis of this condition. In this review, we summarize findings from studies evaluating retinal, retinal nerve fiber layer, and choroidal thickness changes in patients with amblyopia. Focusing on the largest and most recent studies, we discuss common limitations and confounding variables in these studies. We summarize recent advances in ocular imaging technology and reconcile the findings of early histological reports with those of structural OCT in amblyopia.

Optical Coherence Tomography Angiography: Are There Any Changes in Measurements After Strabismus Surgery?

PURPOSE

To evaluate the possible hemodynamic changes following strabismus surgery via optical coherence tomography angiography.

METHODS

Thirty-two eyes of 16 patients who underwent strabismus surgery in one eye were included in the study. Fellow eyes were used as a control group. The vessel densities of the superficial and deep capillary plexus and superficial and deep foveal avascular zones were measured preoperatively and 3 months postoperatively.

RESULTS

The mean superficial and deep foveal avascular zones measurements were 0.84 ± 0.09 and 0.76 ± 1.13 mm², respectively. The mean vessel density of the superficial capillary plexus was 1.23 ± 0.12 and 11.13 ± 1.04 mm² preoperatively in the 1- and 3-mm zones, respectively, whereas the mean vessel density of the deep capillary plexus was 1.13 ± 0.16 and 10.11 ± 1.28 mm² preoperatively. Postoperatively, the mean superficial and deep foveal avascular zones changed to 0.20 ± 0.13 and 0.23 ± 0.12 mm², respectively. Postoperatively, the mean vessel density of the superficial capillary plexus changed to 1.47 ± 0.11 and 12.75 ± 1.10 mm², and the mean vessel density of the deep capillary plexus changed to 1.56 ± 0.12 and 13.91 ± 1.35 mm² in 1- and 3-mm zones, respectively. There was a statistically significant increase in vessel density measurements of the superficial and deep capillary plexus, and a statistically significant decrease in measurements of the superficial and deep foveal avascular zone postoperatively (P < .05). In the fellow eyes, there was no statistically significant change in any of the measurements (P > .05).

CONCLUSIONS

Following strabismus surgery, vessel density of the fovea may increase and the foveal avascular zone may decrease according to optical coherence tomography angiography measurements. [J Pediatr Ophthalmol Strabismus. 2019;56(2):95-100.].