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

Short-Term Morpho-Functional Changes before and after Strabismus Surgery in Children Using Structural Optical Coherence Tomography: A Pilot Study

PURPOSE

To evaluate the immediate alterations in the thickness of the macular ganglion cell-inner plexiform layer (mGCIPL), peripapillary retinal nerve fiber layer (RNFL), inner retinal layer (IRL), and outer retinal layer (ORL) using spectral domain optical coherence tomography (SD-OCT) subsequent to strabismus surgery in pediatric patients diagnosed with horizontal esotropia.

METHODS

Twenty-eight eyes from twenty-one child patients who had undergone uncomplicated horizontal rectus muscle surgery due to strabismus were included. Measurements of RNFL, mGCL-IPL, IRL, and ORL using structural OCT were conducted both before the surgery and one month after the surgical procedure. Importantly, a control group comprising 14 healthy eyes, matched for age and significant refractive error (<3.00 diopters), was included in the current analysis.

RESULTS

Our analysis indicated no significant disparity before and after surgery in terms of best-corrected visual acuity (BCVA), RNFL, IRL, and ORL. Conversely, concerning the macular ganglion cell layer-inner plexiform layer analysis, a substantial increase in mGCL-IPL was observed following the surgical intervention. The mean mGCL-IPL measured 60.8 ± 9.2 μm at baseline and 66.1 ± 13.2 μm one month after the surgery (p = 0.026). Notably, comparison between the strabismus group at baseline and the healthy group revealed a significant reduction in mGCL-IPL in the strabismus group (60.8 ± 9.2) compared to the healthy control group (68.3 ± 7.2; p = 0.014).

CONCLUSIONS

Following strabismus surgery, our observations pointed towards a thickening of the mGCL-IPL layer, which is likely attributable to transient local inflammation. Additionally, we identified a significant differentiation in the mGCL-IPL complex between the pediatric patient group with strabismus and the control group.

Assessment of macular choroidal and retinal thickness: a cohort study in Tibetan healthy children

This research investigates the distribution, progressive changes, and contributing factors of macular choroidal and retinal thickness in Tibetan children utilizing swept-source optical coherence tomography (SS-OCT). The Lhasa childhood study recruited 1632 students from seven primary schools in Lhasa. These participants underwent OCT and ophthalmological evaluations, encompassing retinal and choroidal thickness measurements, refractive error, axial length (AL), and systemic examinations. The median age of the scholars was 8.57 ± 0.50 years with a median spherical equivalent (SE) of 0.19 ± 1.28D. Multivariate regression analysis revealed that thinner macular choroid thickness was correlated with lower value of SE, worse best-corrected visual acuity, higher mean arterial blood pressure (MABP) and boys, while retinal thickness was associated with better image quality and lower value of SE. The choroid and retina were significantly thinner in myopic children. SE was positively related to the thickness of all choroidal and full retinal subregions. In comparison to baseline data from 20 months prior, most regions of the full retina had significantly thinned. Choroidal thickness of Tibetan children is thinner than that of same-age children from other regions. Thinning of retina, the outer-sector GCC and GCIPL may be specified as a follow-up and prognostic indicator for myopia.

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.

Evaluation of Macula and Optic Disc of Adult Amblyopia Patients with Diverse Etiologies using Optical Coherence Tomography Angiography

PURPOSE

To compare macula and optic-disc optical coherence tomography angiography (OCTA) metrics of adult amblyopic eyes with healthy controls and investigate whether these differ according to amblyopia etiology.

METHODS

This cross-sectional study included 35 unilateral amblyopic adults (n = 35 eyes) and 35 age-matched healthy controls (n = 35 eyes). Amblyopia subgroups consisted of anisometropic (n = 12 eyes), strabismic (n = 12 eyes), and combined-mechanism amblyopia (n = 11 eyes). Foveal avascular zone area (FAZA), vessel density (VD), and retinal thickness were obtained using OCTA. Retinal thicknesses were measured at the fovea, parafovea, perifovea, and retinal nerve fiber layer. Foveal, parafoveal, perifoveal, whole-macula, intradisc, peripapillary, and whole-disc VD were recorded. Groups were compared regarding OCTA metrics after adjusting for axial length, spherical equivalent, age, gender, and signal quality index using a one-way analysis of covariance test.

RESULTS

Amblyopic eyes had significantly lower foveal, parafoveal, perifoveal, whole-macula VD in superficial capillary plexus (SCP), and deep capillary plexus (DCP) than control eyes after adjusting for confounders (P < 0.05 for all). All amblyopia subgroups had significantly lower parafoveal, perifoveal, and whole-macula VD in SCP and DCP than control eyes after adjusting for confounders (P < 0.05 for all). There was no significant difference in retinal thickness, FAZA, intradisc VD, peripapillary VD, and whole-disc VD between amblyopic and control eyes, as well as amblyopia subgroups and control eyes.

CONCLUSION

These results suggest that effect of amblyopia on macular microvasculature should be considered when interpreting OCTA metrics of adults with concomitant diseases. It also supports that adult amblyopic eyes of different etiology have similar microvascular features.

Comparison of Retinal and Choroidal Microvasculature Changes in Monocular Amblyopic and Non-amblyopic Eyes following Short-term Patch Occlusion Treatment

PURPOSE

Our objective was to investigate whether there were differences in the short-term changes of retinal and choroidal microvasculature between amblyopic and non-amblyopic eyes after patch occlusion treatment in patients with monocular amblyopia. Additionally, we aimed to determine if these changes were associated with improvements in clinical parameters.

METHODS

We conducted a retrospective, longitudinal paired-eye case-control study by analyzing the medical records of patients under the age of 12 who had monocular amblyopia and underwent patch occlusion treatment for a duration of 2 to 12 months. Using optical coherence tomography angiography images, we compared the foveal avascular zone width, retinal blood vessel density (VD), choroidal thickness (CT), and choroidal vascularity index (CVI) in amblyopic and non-amblyopic eyes before and after patch occlusion treatment. We analyzed the correlations between the aforementioned parameters and changes in best-corrected visual acuity (BCVA) and stereopsis.

RESULTS

Overall, 114 eyes from 57 patients were enrolled. At baseline, parafoveal superficial plexus VD, foveal and parafoveal deep capillary plexus VD (DCPD) were lower by 0.994 ± 3.312% (p = .026), 2.403 ± 8.273% (p = .033), and 2.469 ± 4.095% (p < .001), respectively; CT was thicker by 30.6 ± 90.7 μm (p = .014); and CVI was higher by 1.920 ± 3.432% (p < 001) in the amblyopic eyes than in the non-amblyopic eyes. Following short-term patch occlusion treatment, foveal and parafoveal DCPD increased by 1.264 ± 3.829% (p = .017) and 1.028 ± 3.662% (p = .036), respectively, CT thinned by 15.5 ± 51.5 μm (p = .019), and CVI decreased by 1.296 ± 3.997% (p = .018) in the amblyopic eyes. Following patch occlusion treatment, as the foveal DCPD decreased and CVI increased, the BCVA improved (p = .017 and .035, respectively).

CONCLUSION

Following patch occlusion treatment, increased foveal DCPD and decreased CVI were associated with improved BCVA.

Short-term effects of occlusion therapy and optical correction on microvasculature in monocular amblyopia: a retrospective case-control study

This retrospective longitudinal case-control study investigated the short-term effects of patch occlusion treatment compared with optical correction on the microvasculature in monocular amblyopia. We included patients with monocular amblyopia treated for 2-12 months; they were classified into two groups according to the treatment regimen: patch occlusion or optical correction. Children aged < 12 years who presented to our clinic for examination without amblyopia diagnosis were enrolled as the control group. Changes in retinal and choroid microvasculature according to treatment were examined, and the correlation between changes in microvasculature and improvement in best-corrected visual acuity (BCVA) was evaluated. There were 57, 35, and 41 patients in the patch occlusion, optical correction, and control groups, respectively (mean age, 6.4 ± 2.0 years). Both amblyopic groups showed changes in the foveal and parafoveal deep capillary plexus vessel density (DCPD), choroidal thickness, and choroidal vascularity index (CVI) following short-term treatment (mean, 4.5 months). In the patch occlusion group, BCVA improved as the foveal DCPD increased (P = 0.013) and the CVI decreased (P = 0.037). In the optical correction group, BCVA improved as the foveal and parafoveal DCPD increased (P = 0.009). Increased foveal DCPD following amblyopia treatment and decreased CVI by patch occlusion were associated with improved BCVA.

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.

Evaluation of Macular Ganglion Cell-Inner Plexiform Layer in Children with Deprivational Amblyopia Who Underwent Unilateral Cataract Surgery

Background and Objectives: The aim of the study is to assess macular ganglion cell and inner plexiform layer (mGCIPL) thickness in deprivational amblyopic eyes (AE), fellow non-amblyopic eyes (FE) and normal eyes (NE) using spectral. domain optical coherence tomography (SD-OCT). Materials and Methods: Twenty two children (64% boys) who underwent surgical removal of unilateral congenital or developmental cataracts and exhibited visual impairment despite postoperative visual rehabilitation were included in the study. Cataract surgery was performed in patients aged 55.82 ± 35.85 months (range 6 to 114 months). The mean age of the study group was 9.73 ± 2.85 years (range 5 to 15 years). The comparison group consisted of 22 healthy age- and gender-matched children. The best corrected visual acuity (BCVA) after surgery was: 0.75 ± 0.27 (range 0.3 to 1.3) in AE, 0.1 ± 0.13 (range 0 to 0.5) in FE and 0.04 ± 0.07 (range 0 to 0.2) in NE. OCT scans were performed in all patients and subsequently corrected for axial length related magnification errors. Results: The average thickness of mGCIPL was 70.6 ± 11.28 μm in AE; 77.50 ± 6.72 μm in FE and 81.73 ± 5.18 μm in NE. We found that mGCIPL was statistically significantly thinner in deprivation AE compared to FE (p = 0.038) and NE (p = 0.0005). The minimum thickness of mGCIPL was respectively: 62.68 ± 13.2 μm, 70.3 ± 7.61 μm, and 74.5 ± 5.47, and also differed between AE and FE (p = 0.023) and AE and NE (p = 0.0004). Also, measurements in the inferior, inferotemporal, and superotemporal sectors showed thinning of mGCIPL in AE compared to NE. Conclusions: This analysis may suggest that deprivational amblyopia caused by unilateral congenital or developmental cataract in children may be associated with mGCIPL thinning.

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.

The iridocorneal angle and related anterior segment structures in pediatric anisohyperopic amblyopic eyes

Objectives:

We aimed at investigating the iridocorneal angle, anterior segment structural differences, and their relationship in pediatric anisohyperopic amblyopic eyes.

Methods:

This study was designed as an observational case-control study. We prospectively evaluated the pediatric patients who were newly diagnosed with hyperopic anisometropic amblyopia. Iridocorrneal angle in four sectors, axial length, and anterior segment structures were compared to emmetropic fellow and control eyes using Pentacam and IOLMaster 700 devices. The anisohyperopia and iridocorneal angle related factors were determined in hyperopic anisometropic amblyopic eyes.

Results:

Forty-three hyperopic anisometropic amblyopic eyes, 43 fellow eyes, and 44 control eyes were included. The mean axial length, anterior chamber volume, and anterior chamber depth were significantly reduced in the study eyes compared to the fellow (p < 0.001, p = 0.021, and p = 0.045, respectively) and control eyes (p < 0.001, p = 0.001, and p = 0.009, respectively). The average iridocorneal angle was significantly lower in the study eyes than in the fellow and control eyes (p < 0.001 and p = 0.018, respectively). The iridocorneal angle correlated with anterior chamber depth (r = 0.49, p = 0.013), anterior chamber volume (r = 0.42, p = 0.038), the anterior radius of curvature (r =−0.54, p = 0.005), the posterior radius of curvature (r =−0.58, p = 0.002), and lens thickness (Rho =−0.41, p = 0.033) in the study eyes. Anisohyperopia was related to the interocular difference in axial length (Rho = 0.53, p = 0.005), anterior chamber depth (Rho = 0.53, p = 0.005), and anterior chamber volume (Rho = 0.42, p = 0.031).

Conclusion:

Pentacam and IOLMaster 700 are suitable for non-contact imaging of iridocorneal angle and anterior segment structures in the pediatric age. These biometric differences and their relationship should be kept in mind whenever anterior or posterior segment surgery is planned for pediatric anisohyperopic amblyopic eyes.

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.

Assessment of Foveal Avascular Zone and Macular Vascular Plexus Density in Children With Unilateral Amblyopia: A Systemic Review and Meta-Analysis

Purpose: To examine the quantitative measurements of OCTA in children with amblyopia using the meta-analysis methodology. Methods: PubMed, Embase, and Cochrane library were searched for available papers up to March 2021. Weighted mean differences (WMD) were used to compare the retina parameters between the eyes with amblyopia and the contralateral eyes or healthy control eyes. Results: Twelve studies were included. When considering the parafovea, the microvessel density was reduced in amblyopic eyes compared with healthy control eyes in the superficial capillary plexus (SCP) in 6 × 6 volume scan (WMD = -2.12, 95%CI: -3.24, -0.99) but not SCP in 3 × 3 volume scan (WMD = -1.43, 95%CI: -2.96, 0.11). In the deep capillary plexus (DCP), amblyopia did not decrease vessel density in the 6 × 6 volume scan (WMD = -2.22, 95%CI: -5.86, 1.42; I ² = 79.6%, P = 0.008), but a difference was observed in the whole eye 3 × 3 (WMD = -1.95, 95%CI: -3.23, -0.67; I ² = 27.5%, P = 0.252). There were no significant differences in the foveal avascular zone area and foveal thickness between amblyopic eyes and healthy control eyes. There were no significant differences in microvessel density, foveal avascular zone area, and foveal thickness between amblyopic eyes and fellow eyes. Conclusion: According to OCTA, amblyopic eyes had lower vessel density in parafoveal SCP and DCP compared with healthy control eyes, but not compared with fellow eyes. There were no significant differences regarding the foveal avascular zone area and foveal thickness between amblyopic and non-amblyopic eyes.