Perfusion Deficits in Diabetes Without Retinopathy Localize to the Perivenular Deep Capillaries Near the Fovea on OCT Angiography

Purpose

To localize early capillary perfusion deficits in patients with diabetes mellitus (DM) without clinical diabetic retinopathy (DR) using averaged OCT angiography (OCTA).

Design

Retrospective cross-sectional study.

Participants

Patients with DM without DR and healthy controls.

Methods

We measured perfusion deficits in the full retina, superficial capillary plexus (SCP), and deep capillary plexus (DCP) on averaged 3 × 3-mm OCTA images. Perfusion deficits were defined as the percentage of retinal tissue located >30 μm from blood vessels, excluding the foveal avascular zone (FAZ). One eye from each patient was selected based on image quality. We measured deficits in the parafoveal region, the 300 μm surrounding the FAZ, and 300 to 1000 μm surrounding the FAZ. If a capillary layer within one of these regions was significantly different in DM without DR compared with controls, we further characterized the location of perfusion deficit as periarteriolar, perivenular, or the capillaries between these 2 zones.

Main Outcome Measures

Location of increased perfusion deficits in patients with DM without DR compared with controls.

Results

Sixteen eyes from 16 healthy controls were compared with 16 eyes from 16 patients with DM without DR (age 45.1 ± 10.7 and 47.4 ± 15.2 years respectively, P = 0.64). Foveal avascular zone area and perfusion deficits in the entire parafovea and the 300 to 1000-μm ring around the FAZ were not significantly different between groups (P > 0.05 for all). Perfusion deficits in 300 μm around the FAZ were significantly increased in patients with DM without DR in full retinal thickness, SCP, and DCP (P < 0.05 for all). When analyzing the perivenular, periarteriolar, and capillary zones, only the perivenular DCP perfusion deficits were significantly increased (5.03 ± 2.92% in DM without DR and 2.73 ± 1.97% in controls, P = 0.014).

Conclusions

Macular perfusion deficits in patients with DM without DR were significantly increased in the region nearest the FAZ, mainly at the perivenular deep capillaries. Further research on these early changes may improve our understanding of the capillaries most susceptible to vascular injury and disruption during diabetes.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Evaluation of Posterior Ocular Blood Flow in Diabetic Retinopathy Patients Without Macular Edema Using Optical Coherence Tomography Angiography

AIM

The objective of this study is to investigate and compare the superficial and deep vascular structures of the retina, as well as the changes in the choriocapillaris (CC) and optic disc microvasculature, using optical coherence tomography angiography (OCTA) in patients diagnosed with diabetes mellitus (DM) without diabetic retinopathy (DR), patients with non-proliferative and proliferative DR, and healthy individuals.

MATERIALS AND METHODS

This prospective study conducted between July 2020 and July 2021 included patients diagnosed with type 2 DM without DR, as well as patients with mild nonproliferative, moderate nonproliferative, and proliferative DR without macular oedema. A control group of 25 age- and gender-matched healthy individuals was also included. OCTA parameters of the patients were examined.

RESULTS

In the DR groups, compared to the control group, there was a significant decrease in macular superficial, deep, and CC perfusion areas as the severity of DR increased (p<0.001). The vascular density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) exhibited a statistically significant decrease in all quadrants of the DR group compared to the control group (p = 0.033 for SCP in the fovea, p<0.001 for all other quadrants). The superficial and deep FAZs showed a significant expansion in the DR group compared to the control group (p = 0.003 for superficial FAZ, p<0.001 for deep FAZ). As the severity of DR increased, there was a statistically significant decrease in the perfusion areas of the optic nerve head (ONH), radial peripapillary capillary (RPC), and vitreous segments (p<0.001 for ONH, p = 0.031 for RPC, p<0.001 for vitreous). There was a statistically significant decrease in RPC VD in all quadrants as the severity of DR increased. Moreover, as the severity of DR increased, a statistically significant decrease in the VD of the ONH was observed in all quadrants except for the inferior nasal (p = 0.094), inferior temporal (p = 0.111), superior temporal (p = 0.18), and temporal (p = 0.284) quadrants.

CONCLUSION

Our study demonstrated the involvement of macular and optic nerve perfusion areas (PA) and VD in diabetic patients. OCTA proved to be a valuable and noninvasive imaging modality, providing an easy and repeatable assessment of posterior segment vascular changes in patients with DR.

Paracentral acute middle maculopathy presenting as a sign of impending central retinal artery occlusion: a case report

BACKGROUND

To report a case of paracentral acute middle maculopathy (PAMM) that progressed to central retinal artery occlusion (CRAO) on spectral domain-optical coherence tomography (SD-OCT).

CASE PRESENTATION

A 63-year-old male presented with a paracentral scotoma that began several days ago. His past medical history consisted of third-degree atrioventricular heart block requiring a pacemaker. Giant cell arteritis was unlikely given the patient's labs, demographics and review of systems. SD-OCT revealed a characteristic hyperreflective band in the inner nuclear layer consistent with PAMM in his left eye. Fluorescein angiography was obtained and was unremarkable. Five days later, the patient developed no light perception in the left eye. SD-OCT showed a diffuse inner retinal hyperreflectivity consistent with CRAO.

CONCLUSION

PAMM can be a harbinger event for complete CRAO. Complete stroke evaluation should be performed to prevent a cerebrovascular event or progression to complete blindness in the involved eye.

Quantitative analysis of retinal microvascular structure and correlation with ocular parameters: A normative database of pediatric OCT angiography

PURPOSE

To analyze the vascular structure of the healthy pediatric population using optical coherence tomography angiography (OCTA), and to investigate its relationship with ocular parameters.

MATERIALS AND METHOD

This cross-sectional, prospective study included 142 eyes of 71 healthy subjects aged 8-18 years. All patients underwent a complete ocular assessment, biometric evaluation and OCTA analysis. Anterior chamber depth, axial length, corneal thickness values were also reported and their relationship with OCTA measurements was evaluated.

RESULTS

There was no statistical difference between girls and boys in terms of demographic characteristics (p>0.05). Neither vascular density in the deep and superficial capillary plexus nor FAZ area was significantly related to the ocular parameters or age of any patient in the study.

CONCLUSIONS

Despite the relatively small number of participants, this study may represent normative data for the Turkish pediatric population. It was also shown that vascular density and FAZ area in childhood are not affected by age, axis length, anterior chamber depth, cornea and foveal thickness.

Deep Capillary Plexus as Biomarker of Peripheral Capillary Nonperfusion in Central Retinal Vein Occlusion

Purpose

To identify the vascular biomarkers of peripheral capillary nonperfusion in patients affected by naive central retinal vein occlusion (CRVO), and to analyze their changes over the follow-up.

Study Design

Consecutive prospective case series with a planned follow-up of 2 years.

Participants

Thirty-five patients affected by CRVO and 35 healthy gender- and age-matched subjects were enrolled in the study.

Methods

Ophthalmic examination included best corrected visual acuity (BCVA), ultrawidefield fluorescein angiography (UWFFA), OCT, and OCT angiography (OCTA).

Main Outcome Measures

Vessel density (VD) at the superficial capillary plexus and deep capillary plexus (DCP) were calculated on OCTA images. The ischemic index (ISI) was calculated on UWFFA.

Results

The mean baseline ISI was 37%, increasing to 40% at the end of the follow-up, whereas it was 4.9% in the patients' fellow eyes and 4.5% in the control group with no change over the follow-up. OCT angiography revealed VD reduction in the DCP, considering both 3 × 3 mm and 12 × 12 mm scans. The correlation analyses revealed that DCP VD was the only parameter showing a statistically significant correlation with the foveal avascular zone (FAZ) area, BCVA, and ISI.

Conclusions

Deep capillary plexus VD impairment is detectable in all CRVO cases, variably involving both the central retina (with enlarged FAZ) and the periphery (with VD reduction in the peripheral retina). The severity of DCP VD reduction has correlates with various clinical markers. Deep capillary plexus VD may represent a crucial biomarker to characterize CRVO, and further studies are necessary to identify the cutoff thresholds for the different clinical manifestations.

Deep Capillary Nonperfusion on OCT Angiography Predicts Complications in Eyes with Referable Nonproliferative Diabetic Retinopathy

OBJECTIVE

To evaluate the ability of capillary nonperfusion parameters on OCT angiography (OCTA) to predict the development of clinically significant outcomes in eyes with referable nonproliferative diabetic retinopathy (NPDR).

DESIGN

Prospective longitudinal observational study.

SUBJECTS

In total, 59 patients (74 eyes) with treatment-naive moderate and severe (referable) NPDR.

METHODS

Patients were imaged with OCTA at baseline and then followed-up for 1 year. We evaluated 2 OCTA capillary nonperfusion metrics, vessel density (VD) and geometric perfusion deficits (GPDs), in the superficial capillary plexus, middle capillary plexus (MCP), and deep capillary plexus (DCP). We compared the predictive accuracy of baseline OCTA metrics for clinically significant diabetic retinopathy (DR) outcomes at 1 year.

MAIN OUTCOME MEASURES

Significant clinical outcomes at 1 year, defined as 1 or more of the following-vitreous hemorrhage, center-involving diabetic macular edema, and initiation of treatment with pan-retinal photocoagulation or anti-VEGF injections.

RESULTS

Overall, 49 patients (61 eyes) returned for the 1-year follow-up. Geometric perfusion deficits and VD in the MCP and DCP correlated with clinically significant outcomes at 1 year (P < 0.001). Eyes with these outcomes had lower VD and higher GPD, indicating worse nonperfusion of the deeper retinal layers than those that remained free from complication. These differences remained significant (P = 0.046 to < 0.001) when OCTA parameters were incorporated into models that also considered sex, baseline corrected visual acuity, and baseline DR severity. Adjusted receiver operating characteristic curve for DCP GPD achieved an area under the curve (AUC) of 0.929, with sensitivity of 89% and specificity of 98%. In a separate analysis focusing on high-risk proliferative diabetic retinopathy outcomes, MCP and DCP GPD and VD remained significantly predictive with comparable AUC and sensitivities to the pooled analysis.

CONCLUSIONS

Evidence of deep capillary nonperfusion at baseline in eyes with clinically referable NPDR can predict short-term DR complications with high accuracy, suggesting that deep retinal ischemia has an important pathophysiologic role in DR progression. Our results suggest that OCTA may provide additional prognostic benefit to clinical DR staging in eyes with high risk.

Superficial capillary plexus vessel density/deep capillary plexus vessel density ratio in healthy eyes

BACKGROUND

To identify factors differently affecting the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in healthy eyes using their vessel density (VD) ratio.

METHODS

Healthy eyes were enrolled. The ratio between the VD of SCP and DCP (SVD/DVD ratio) was calculated. Pearson correlation analyses were performed to identify the relationships between this ratio and other factors.

RESULTS

The mean SVD and DVD were 36.2 ± 5.7 and 37.7 ± 4.9%, respectively, and the mean SVD/DVD ratio was 0.96 ± 0.15. The SVD was significantly correlated with the best-corrected visual acuity (BCVA) (r = - 0.368, P <  0.001), age (r = - 0.408, P <  0.001), and OCTA quality (r = 0.520, P <  0.001). The DVD was significantly correlated with the BCVA (r = - 0.150, P = 0.008), age (r = - 0.229, P <  0.001), and OCTA quality (r = 0.555, P <  0.001). Among various factors, age (r = - 0.296, P <  0.001), the BCVA (r = - 0.237, P <  0.001), axial length (r = 0.234, P <  0.001), and OCTA quality (r = 0.270, P < 0.001) were significantly correlated with the SVD/DVD ratio.

CONCLUSIONS

Age, BCVA, axial length, and OCTA image quality were significantly correlated with the SVD/DVD ratio. Age, the BCVA, and OCTA quality were more strongly correlated with the SCP, and the axial length was more strongly correlated with the DCP.

Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies

PURPOSE

To characterize and distinguish non-neovascular deep retinal age-related microvascular anomalies (DRAMA) from type 3 macular neovascularization (MNV) using volume rendering of OCT and OCT angiography (OCTA).

DESIGN

Retrospective, consecutive case series.

SUBJECTS

Consecutive patients with age-related macular degeneration (AMD) exhibiting de novo non-neovascular abnormalities within the deep vascular plexus (DCP), as detected using high-resolution (High-Res) spectral-domain (SD) and swept-source (SS) OCT or OCTA. Patients with retinal vascular alterations attributable to other disease entities were excluded.

METHODS

Complete ophthalmic examination and multimodal imaging, including confocal fundus photography (CFP), SD-OCT, High-Res SD-OCT and OCTA, and volume-averaged SS-OCTA. The volume renderings of High-Res OCTA and averaged SS-OCTA were used to analyze capillary abnormalities and inflow or outflow connectivity pathways.

MAIN OUTCOME MEASURES

The primary outcomes were the characteristics of capillary abnormalities (number, size, shape, reflectivity, and location) and inflow or outflow connectivity pathways. The secondary outcomes were nearby changes in CFP and structural OCT (hyperreflective foci [HRF], outer retinal atrophy, and retinal pigment epithelium [RPE] atrophy).

RESULTS

From 8 eyes of 8 patients, 2 subtypes of DRAMA were identified: small-diameter perifoveal capillary dilations with hyperreflective walls within the inner nuclear layer (type 1, n = 4) and vascular outpouchings, typically multiple, extending posteriorly into the Henle fiber layer, with reflectivity similar to adjacent normal retinal capillaries (type 2, n = 10). Four eyes had both subtypes of DRAMA. The 3-dimensional visualization of OCTA data demonstrated DRAMA corresponding to the dilations of DCP capillaries without direct inflow or outflow connections to the superficial plexus. Fundus photographs showed circular red dots in 3 eyes, all corresponding to type 1 DRAMA. In all the cases, DRAMA colocalized with HRF. No lesions were found anterior to the areas of the RPE or outer retina atrophy. Asymptomatic intraretinal exudation varied through a follow-up duration of up to 6 years, with no lesions progressing to type 3 MNV.

CONCLUSIONS

In eyes with non-neovascular AMD, DRAMA include 2 types of capillary dilations occurring without the remodeling of the surrounding vascular network. Deep retinal age-related microvascular anomalies can resemble microvascular changes due to other causes and can masquerade as type 3 MNV. Mild intraretinal exudation can vary during follow-up, without progression to type 3 MNV.

OCT and OCTA evaluation of vascular and morphological structures in the retina in recovered pediatric patients with COVID-19

BACKGROUND

Using OCT and OCTA imaging, we aimed to determine whether COVID-19 induces pathological changes in vascular and morphological structures in the pediatric retina.

METHODS

The current prospective, cross-sectional, observational clinical study included recovered pediatric patients with COVID-19 evaluated between May 2020 and June 2020. Retinal vascular (radial peripapillary, superficial, and deep capillary plexus vessel densities) and morphological (peripapillary retinal nerve fiber, ganglion cell layer, retinal, and choroidal thickness) in the optic disk and macula regions were quantitively assessed using OCT and OCTA. Data were compared between COVID-19 patients and age-matched controls.

RESULTS

The COVID-19 group included 32 eyes of 16 patients and the control group included 32 eyes of 16 cases. Fundus and biomicroscopic examinations revealed no signs of pathology in the COVID-19 group. Mean peripapillary retinal nerve fiber, ganglion cell layer, and choroidal thickness values were significantly greater in the COVID-19 group than in the control group (p<0.05). OCTA indicated that mean superficial and deep capillary plexus vessel densities, and choriocapillaris flow area values were significantly lower in the COVID-19 group than in the control group, whereas mean radial peripapillary capillary plexus vessel density values were significantly higher (p<0.05).

CONCLUSIONS

Even if fundus examination results appear normal in pediatric patients with COVID-19, vascular and morphological changes may be observed in the retina. Further studies with larger numbers of patients are needed to elucidate the clinical significance of vascular and morphological changes in this population.

Deep Capillary Geometric Perfusion Deficits on OCT Angiography Detect Clinically Referable Eyes with Diabetic Retinopathy

PURPOSE

To evaluate the sensitivity (SN) and specificity (SP) of OCT angiography (OCTA) parameters for detecting clinically referable eyes with diabetic retinopathy (DR) in a cohort of patients with diabetes mellitus (DM).

DESIGN

Retrospective, cross-sectional study.

SUBJECTS

Patients with DM with various levels of DR.

METHODS

We measured vessel density, vessel length density (VLD), and geometric perfusion deficits (GPDs) in the full retina, superficial capillary plexus (SCP), and deep capillary plexus (DCP) on 3 × 3-mm OCTA images. Geometric perfusion deficit was recently described as retinal tissue located further than 30 μm from blood vessels, excluding the foveal avascular zone (FAZ). We modified the GPD metric by including the FAZ as an additional variable. Clinically referable eyes were defined as moderate nonproliferative DR (NPDR) or worse retinopathy, or diabetic macular edema (DME). One eye from each patient was selected for the analysis based on image quality. We used a binary logistic regression model to adjust for covariates.

MAIN OUTCOME MEASURES

Sensitivity, SP, and area under the curve (AUC).

RESULTS

Seventy-one of 150 included eyes from 150 patients (52 with DM without DR, 27 with mild NPDR, 16 with moderate NPDR, 10 with severe NPDR, 30 with proliferative DR, and 15 with DME) had clinically referable DR. Geometric perfusion deficit metric that included the FAZ performed better than GPD in detecting referable DR in the SCP (P = 0.025) but not the DCP or full retina (P > 0.05 for both). Deep capillary plexus GPD had the largest AUC for detecting clinically referable eyes (AUC = 0.965, SN = 97.2%, SP = 84.8%), which was significantly larger than the AUC for vessel density of any layer (P < 0.05 for all) but not DCP VLD (P = 0.166). The cutoff value of 2.5% for DCP GPD resulted in a highly sensitive test for detecting clinically referable eyes without adjusting for covariates (AUC = 0.955, SN = 97.2%, SP = 79.7%).

CONCLUSIONS

Vascular parameters in OCTA, especially in the DCP, have the potential to identify eyes that warrant further evaluation. Geometric perfusion deficits may better distinguish these clinically referable eyes with DR than standard vessel density parameters.

Subclinical Retinal Capillary Abnormalities in Juvenile Systemic Lupus Erythematosus without Ocular Involvement

PURPOSE

This study aimed to evaluate subclinical retinal microvascular changes with OCTA in juvenile systemic lupus erythematosus (JSLE) patients without ocular involvement.

METHODS

Ten eyes of 10 JSLE and 13 eyes of 13 age and sex-matched healthy controls (HCs) were enrolled. The superficial (SCP) and deep capillary plexus (DCP), FAZ parameters, the flow area of the outer retina, and choriocapillaris were evaluated using OCTA.

RESULTS

All vessel density (VD) parameters in DCP were significantly lower in JSLE group compared to HCs. There was no significant difference between the groups in VD parameters of both SCP and ONH, FAZ, outer retina and choriocapillaris flow area. All DCP VD parameters showed a good ability to differentiate JSLE from HCs.

CONCLUSION

OCTA could detect retinal vascular impairment in the deep macular region in JSLE patients with normal ocular examination. Furthermore, all DCP VD parameters have a good ability to discriminate JSLE from HCs.

Evaluation of radiation maculopathy after treatment of choroidal melanoma with ruthenium-106 using optical coherence tomography angiography

BACKGROUND

To assess the impact of brachytherapy on macular microvasculature utilizing optical coherence tomography angiography (OCTA) in treated choroidal melanoma.

METHODS

In this retrospective observational case series, we reviewed the recorded data of the patients with unilateral extramacular choroidal melanoma treated with ruthenium - 106 (¹⁰⁶Ru) plaque radiotherapy with a follow-up period of more than 6 months. Automatically measured OCTA retinal parameters were analysed after image processing.

RESULTS

Thirty-one eyes of 31 patients with the mean age of 51.1 years were recruited. Six eyes had no radiation maculopathy (RM). From 25 eyes with RM, nine eyes (36%) revealed a burnout macular microvasculature with imperceptible vascular details. Twenty-one non-irradiated fellow eyes from the enrolled patients were considered as the control group. Foveal and optic disc radiation dose had the highest value to predict the burnout pattern (ROC, AUC: 0.763, 0.727). Superficial and deep foveal avascular zone (FAZ) were larger in irradiated eyes in comparison to non-irradiated fellow eyes (1629 μm² vs. 428 μm², P = 0.005; 1837 μm² vs 268 μm², P = 0.021; respectively). Foveal and parafoveal vascular area density (VAD) and vascular skeleton density (VSD) in both superficial and deep capillary plexus (SCP and DCP) were decreased in all irradiated eyes in comparison with non-irradiated fellow eyes (P < 0.001). Compared with non-irradiated fellow eyes, irradiated eyes without RM had significantly lower VAD and VSD at foveal and parafoveal DCP (all P < 0.02). However, these differences at SCP were not statistically significant.

CONCLUSION

The OCTA is a valuable tool for evaluating RM. Initial subclinical microvascular insult after ¹⁰⁶Ru brachytherapy is more likely to occur in DCP. The deep FAZ area was identified as a more critical biomarker of BCVA than superficial FAZ in these patients.

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.

The role of quantitative deep capillary plexus in the pathogenesis of type 3 macular neovascularization: an optical coherence tomography angiography study

Purpose

To quantitatively investigate the role of deep capillary plexus (DCP) in patients affected by type 3 macular neovascularization (MNV), compared to patients with reticular pseudodrusen (RPD) eyes and healthy controls, using optical coherence tomography angiography (OCTA).

Methods

In this prospective observational study, a total of seventy-eight eyes of 78 patients were included. Group 1 consisted of 40 eyes of 40 patients with stage 1 of type 3 MNV (22 males, 18 females, mean age 73.7, SD ± 6.60) and group 2 included 38 eyes of 38 patients with RPD (17 males, 21 females, mean age 73.2, SD ± 4.55). The control group included 40 eyes of 40 healthy subjects (20 males, 20 females, mean age 71.4, SD ± 6.36 years). We evaluated the retinal vessel density (VD) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) using OCTA.

Results

Patients with diagnosis of type 3 MNV showed statistically lower values of VD in DCP with respect to controls and to RPD group (p < 0.001), while there were no statistical differences between RPD and control group in macular region. No significant differences in VD of SCP were detected among the three study groups.

Conclusion

OCTA provides a reproducible, non-invasive detailed quantitative analysis of retinal vascular features and changing in early-stage type 3 MNV patients, which allowed to shed the light on the main role of DCP ischemia in the development of type 3 MNV.

Optical coherence tomography angiography in preterm-born children with retinopathy of prematurity

PURPOSE

To describe the foveal avascular zone (FAZ) and vessel density (VD) in the superficial and deep capillary plexus in children with a history of prematurity on optical coherence tomography angiography (OCTA) and their correlation with gestational age (GA) and birth weight (BW).

METHODS

We enrolled 81 preterm- and eight term-born children in this prospective observational study. The Optovue RTVue AVANTI (Optovue Inc., Fremont, CA) was used to procure the OCTA images. The 3 × 3 mm scan protocol centered on the fovea and the central 1 mm of the grid along with the FAZ of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) was acquired.

RESULTS

The mean SCP-VD was comparable between the preterms and term controls (p = 0.315) in the central fovea (1-mm grid). However, the SCP-VD of the 3-mm grid was lower in the preterms born without ROP, with type 1 ROP, and with type 2 ROP (47.61, 47.90, and 48.82 respectively) compared to that in the term group (51.38; p = 0.031). The FAZ in the SCP (p = 0.003) and DCP (p = 0.003) was significantly smaller in the preterms compared to that in the controls. Based on the GA sub-analysis, the FAZ was significantly smaller in the SCP and DCP of preterms born < 31 weeks and > 31 weeks GA (p < 0.000, p < 0.035, respectively). Based on the BW, the difference between the FAZ in the SCP (p = 0.002) and DCP (p = 0.003) was significant. There was no association between the visual acuity and FAZ.

CONCLUSION

Optical coherence tomography angiography findings in this study show an altered foveal morphology and vascularity in preterms with and without ROP.

Comparison of fundus fluorescein angiography, optical coherence tomography and optical coherence tomography angiography features of macular changes in Eales disease: a case series

Purpose

To study the macular features in Eales disease patients observed with fundus fluorescein angiography (FA), optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA).

Methods

A cross-sectional study was done on treatment naïve 31 eyes (23 patients) with Eales disease. Baseline parameters such as Best-corrected visual acuity (BCVA), slit-lamp bio microscopy (SLB), indirect ophthalmoscopy, FA, spectral-domain OCT {quantitative (central macular thickness [CMT]) and qualitative analysis on SD-OCT} and OCTA were performed. Any media opacity precluding the above investigations was excluded.

Results

Macular findings comprised of- epiretinal membrane, macular exudation, full thickness macular hole, sub internal limiting membrane bleed, cystoid macular oedema, neurosensory detachment and retinal thickening. Sixteen (51.6%) of our patients had macular changes as seen on all modalities together. SLB and indirect ophthalmoscopy missed macular findings in 50% patients and FA in 18.8% patients. OCT and OCTA diagnosed all macular findings. On comparison of mean BCVA in patients with macular involvement on FA, OCT and OCTA, compared to those without macular involvement, patients with macular involvement had lower BCVA (p 0.000, 0.01 and 0.001 respectively). Thus, FA missed many patients who had significant macular involvement and hence less vision.

Conclusion

Eales disease though described in literature as classically being peripheral retina disease process, also has macular involvement. OCT and OCTA are useful guides to evaluation of macular involvement in these patients. The latter seems to be superior to FA in detecting macular abnormalities in this ailment. OCTA is non-invasive and shows deep capillary plexus changes which are not shown by any other modality.

Concurrent vascular flow defects at the deep capillary plexus and choriocapillaris layers in acute macular neuroretinopathy on multimodal imaging: A case series

Purpose

To describe multimodal imaging findings with focus on retinal and choroidal vascular features in acute macular neuroretinopathy (AMN).

Observations

Three eyes from 3 patients (1 man, 2 women) with average age of 31 were included in this retrospective case series at a single institution. Each case showed petaloid hyporeflective areas on infrared images (IR) with variable levels of outer retinal defects on spectral domain optical coherence tomography (OCT). En face OCT angiography (OCT-A) images showed quantifiable reduction in vessel density at levels of the deep capillary plexus (DCP) and choriocapillaris (CC) layers. In 2 of the cases with near-infrared autofluorescence imaging (NIRAF), there were subtle areas of hypoautofluorescence corresponding in location to the lesions seen on IR. In one case, fluorescein angiography (FA) showed a small area of retinal vascular leakage in the area of the IR lesion, and in other 2 cases, there were paracentral areas of hypofluorescence in the area of the IR lesions. En face structural OCT image at the retinal pigment epithelium (RPE) level in each case showed no evidence of projection artifact from the retina.

Conclusions and Importance

The pathogenesis of AMN is suspected to involve a vasogenic insult. However, the precise localization of the vascular insult has been controversial and unclear. Our findings demonstrate that concurrent vascular flow defects in both DCP and CC could be possible in AMN and suggest that an inflammatory and vascular etiology in concert could underlie the pathogenesis of AMN.

Colocalization of optical coherence tomography angiography with histology in the mouse retina

Optical coherence tomography angiography (OCT-A) allows in vivo, non-invasive, functional imaging of retinal perfusion. The purpose of this study was to determine the reliability of OCT-A in visualizing the complete retinal vasculature by comparing in vivo OCT-A images to matched ex vivo retinal tissue in mice. Adult female C57BL/6 mice were imaged to obtain OCT-A images of the superficial vascular complex, intermediate capillary plexus and deep capillary plexus. Z-stack fluorescence images of whole-mounted retinas, labeled for vascular endothelial cells by anti-isolectin immunohistochemistry and FITC-dextran perfusion, were generated. The OCT-A and fluorescence images were manually colocalized and vessel length measured for each of the techniques. Mean vessel length among all plexuses showed less than 13% difference between OCT-A and lectin immunohistochemistry and less than 4% difference between OCT-A and FITC-dextran perfusion. The strength of the correlation between OCT-A and lectin immunohistochemistry ranged from 0.46-0.95, while that between OCT-A and FITC-perfusion ranged from 0.67-0.88. OCT-A visualized retinal vasculature in vivo to a similar extent in matched ex vivo histology images. Our results show that OCT-A is a reliable method for acquiring in vivo images of retinal perfusion in mice, with the ability to differentiate each vascular plexus.

Quantitative evaluation of retinal microvascular circulation in patients with obstructive sleep apnea-hypopnea using optical coherence tomography angiography

PURPOSE

To compare capillaries perfusion in macular areas at different layers and peripapillary region in radial peripapillary capillaries (RPC) between healthy subjects and subjects with obstructive sleep apnea-hypopnea (OSA) using spectral-domain optical coherence tomography angiography (OCTA).

METHODS

Totally 16 eyes with mild-to-moderate OSA, 14 eyes with severe OSA and 22 control eyes were enrolled in this study. Every subject filled out the Berlin questionnaire and received a comprehensive ocular and physical examination. The clinical characteristics were collected, OCT and OCTA scans using OCTA RT XR Avanti (AngioVue software, Optovue Inc., Fremont, CA, USA) were performed and analyzed.

RESULTS

Compared to the control group, the severe group had significantly higher VD in parafovea and perifoveal regions (p = 0.031; p = 0.029) at the level of deep capillary plexus (DCP), whereas the mild-to-moderate group had a significantly lower VD in the peripapillary region on RPC network in disc areas (p = 0.013).

CONCLUSIONS

Blood flow changes in macular areas might first appear at the DCP layer in OSA patients. Reduced VD in the peripapillary region at the RPC layer might be associated with OSA and cause subsequent RNFL changes.

Evaluation of retinal neurovascular structures by optical coherence tomography and optical coherence tomography angiography in children and adolescents with type 1 diabetes mellitus without clinical sign of diabetic retinopathy

BACKGROUND

The aim of the study was to investigate whether retinal neurovascular structural impairment in children and adolescents with type 1 diabetes mellitus (T1D) without clinical signs of diabetic retinopathy (DR) could be detected early via optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

In the current prospective, cross-sectional, observational clinical study children and adolescents with T1D without DR were evaluated between December 2018 and May 2019. Retinal neurovascular structures in the macular and optic disc regions were examined in detail and quantitatively assessed using OCT and OCTA. Data from subjects with T1D were compared with data from healthy controls. Whether retinal neurovascular structural changes were significantly associated with puberty stage, diabetes duration, and HbA1c level was also investigated.

RESULTS

The T1D group included 110 eyes and the control group included 84 eyes. In the T1D group the mean inside disc vessel density (VD) was significantly lower than that of the control group (p < 0.001), as was the mean superior temporal disc VD (p < 0.043). Puberty stage was significantly associated with retinal thickness, parafoveal superficial capillary plexus VD, and peripapillary retinal nerve fiber layer thickness (p < 0.05). Diabetes duration and HbA1c level was significantly correlated with retinal layer thickness, foveal avascular zone diameter, and superficial and deep capillary plexus VDs.

CONCLUSION

In children and adolescents with T1D without clinical signs of DR, the VD of the disc region is affected earlier than the macular region. In these patients, early neurovascular impairment can be detected non-invasively via OCT and OCTA.

Assessment of macular capillary perfusion in patients with inactive Vogt-Koyanagi-Harada disease: an optical coherence tomography angiography study

PURPOSE

To assess macular capillary perfusion in patients with inactive Vogt-Koyanagi-Harada (VKH) disease by using optical coherence tomography angiography (OCTA).

METHODS

A total of 51 eyes of 51 patients with inactive VKH (group 1, n = 23) and healthy volunteers (group 2, n = 28) underwent detailed eye examination including OCTA (RTVue-XR Avanti) scanning. OCTA images (6 × 6 mm) were assessed for central retinal thickness (CRT), subfoveal choroidal thickness (SFCT), vessel densities (VD) in superficial capillary plexus (SCP) and deep capillary plexus (DCP), choriocapillaris (CC) flow area and vessel flow density (VFD), foveal avascular zone (FAZ) area and acircularity index (AI).

RESULTS

The mean ages of group 1 (13 female, 10 male) and group 2 (15 female, 13 male) were 39.9 ± 11.8 (range, 24-58) and 38.9 ± 8.5 (range, 29-51) years, respectively (p = 0.773). CRT and SFCT were 218.2 ± 39.4 μm and 195.6 ± 28.6 μm in group 1, while 243.5 ± 9.7 μm and 316.7 ± 20.1 μm in group 2, respectively (p < 0.05). VD in SCP and DCP were significantly lower in group 1 (50.6 ± 4.7% vs. 54.3 ± 3.4% and 53.9 ± 3.6% vs. 61.1 ± 2.7% respectively; p < 0.05). FAZ areas were 0.32 ± 0.11 mm² in group 1 and 0.25 ± 0.06 mm² in group 2 (p = 0.046). There was no statistically significant difference between groups regarding AI, CC flow area, and VFD (p > 0.05). There was weak negative correlation between BCVA (logMAR) and parafoveal and perifoveal VD in SCP and DCP of group 1 (p < 0.05).

CONCLUSION

Macular capillary perfusion was significantly reduced both in SCP and DCP in patients with inactive VKH disease.

Is there a relationship between hypoparathyroidism and retinal microcirculation?

PURPOSE

To investigate the retinal microvasculature in patients with surgically induced hypoparathyroidism who have no clinical evidence of retinopathy and to compare these data with those of healthy control subjects.

METHODS

Forty patients with a confirmed diagnosis of permanent hypoparathyroidism and no clinical evidence of retinopathy and 37 age- and sex-matched healthy control subjects were included in the study. After complete ophthalmological examination, all patients underwent optical coherence tomography angiography measurement (Optovue Inc., Fremont, California, USA) to assess the foveal avascular zone (FAZ) area; FAZ perimeter; acircularity index of FAZ; foveal density-300; radial peripapillary capillary plexus (RPCP) vessel density; superficial, middle and deep capillary plexus vessel densities (SCP, MCP and DCP). The data from the right eyes of all participants were used for statistical analysis.

RESULTS

The SCP and MCP vessel densities were significantly lower, and the RPCP whole image and peripapillary vessel densities were significantly higher than those in healthy control subjects (p < 0.05 for all). The DCP vessel densities of patients with surgically induced hypoparathyroidism were not significantly different from those of healthy control subjects (p > 0.05 for all). No significant difference was found in the FAZ area, FAZ perimeter, acircularity index of FAZ, foveal density-300 measurements between patients and controls (p > 0.05 for all).

CONCLUSIONS

Reduced retinal vessel density in patients with surgically induced hypoparathyroidism supports the hypothesis that parathyroid hormone is associated with regulation of vascular homeostasis, including macular microcirculation. Increased perfusion in the peripapillary area may suggest an early subclinic effect of hypoparathyroidism.

Effects of iron deficiency anemia on peripapillary and macular vessel density determined using optical coherence tomography angiography on children

PURPOSE

To evaluate retinal vascular parameters by optical coherence tomography angiography (OCT-A) in iron deficiency anemia (IDA).

METHODS

Thirty-two patients with IDA (study group) and 30 healthy children (control group) were enrolled in the study. All subjects underwent a complete ocular examination. OCT-A scans were performed in a 6 × 6 mm area centered on the macula. Foveal avascular zone (FAZ), non-flow area (NFA), FAZ perimeter (PERIM), acircularity index (AI) of FAZ, and foveal density (FD) were measured in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). SCP and DCP were also scanned centered on the optic disk. Hemoglobin (Hb), mean corpuscular volume (MCV), serum iron, total iron-binding capacity (TIBC), and ferritin were also studied and compared for both groups.

RESULTS

The mean age was 12.22 ± 4.48 years (ranged 5-18 years) in the study group and 12.37 ± 3.76 years (ranged 6-18 years) in the control group. The mean FAZ value was 0.290 ± 0.09 mm² in the study group and 0.298 ± 0.11 mm² in the control group. The mean NFA value was 0.477 ± 0.10 mm² in the study group and 0.486 ± 0.13 mm² in the control group (p > 0.05). FD and AI were not statistically significant between the study group and control group (p > 0.05). The mean value for SCP was statistically significant between the study group and control group (p < 0.05). The mean value for DCP was not significantly different between the study and control groups (p > 0.05). The mean values for capillary density on optic disk were also statistically significant between the study group and control group (p < 0.05). A negative correlation was found between serum iron, TIBC, and capillary plexus density (p < 0.05). A positive correlation was found between MCV and ferritin values and capillary plexus density (p < 0.05).

CONCLUSION

IDA had significantly lower capillary plexus density. We detected retinal microvascular changes in young IDA patients before significant ocular anomalies, especially ischemic changes, developed.

Clinically relevant factors associated with quantitative optical coherence tomography angiography metrics in deep capillary plexus in patients with diabetes

Background

To test clinically relevant factors associated with quantitative artifact-free deep capillary plexus (DCP) metrics in patients with diabetes mellitus (DM).

Methods

563 eligible eyes (221 with no diabetic retinopathy [DR], 135 with mild DR, 130 with moderate DR, and 77 with severe DR) from 334 subjects underwent optical coherence tomography-angiography (OCT-A) with a swept-source OCT (Triton DRI-OCT, Topcon, Inc., Tokyo, Japan). Strict criteria were applied to exclude from analysis those DCP images with artifacts and of poor quality, including projection artifacts, motion artifacts, blurriness, signal loss, B-scan segmentation error, or low-quality score. A customized MATLAB program was then used to quantify DCP morphology from the artifact-free DCP images by calculating three metrics: foveal avascular zone (FAZ), vessel density (VD), and fractal dimension (FD).

Results

166 (29.5%) eyes were excluded after quality control, leaving in the analysis 397 eyes (170 with no DR, 101 with mild DR, 90 with moderate DR, 36 with severe DR) from 250 subjects. In the multiple regression models, larger FAZ area was associated with more severe DR (β = 0.687; p = 0.037), shorter axial length (AL) (β = − 0.171; p = 0.003), thinner subfoveal choroid thickness (β = − 0.122; p = 0.031), and lower body mass index (BMI) (β = − 0.090; p = 0.047). Lower VD was associated with more severe DR (β = − 0.842; p = 0.001), shorter AL (β = 0.107; p = 0.039), and poorer visual acuity (VA) (β = − 0.133; p = 0.021). Lower FD was associated with more severe DR (β = − 0.891; p < 0.001) and with older age (β = − 0.142; p = 0.004).

Conclusions

Quantitative artifact-free DCP metrics are associated with VA, DR severity, AL, subfoveal choroidal thickness, age, and BMI in diabetic patients. The effects of ocular and systemic factors should be considered for meaningful interpretations of DCP changes in DM patients.

Foveal vasculature changes and nonperfusion in patients with diabetes types I and II with no evidence of diabetic retinopathy

PURPOSE

To analyze the foveal avascular zone (FAZ) in patients with diabetes and no retinopathy vs. controls using OCT angiography (OCT-A).

METHODS

Prospective, observational clinical study. Type I and II diabetics with no retinopathy and healthy control patients underwent OCT-A. The FAZ size and capillary density were calculated using Image J and Adobe Photoshop CS8. Statistical analysis was performed using one-way ANOVA with Tukey's multiple comparison test and the Pearson correlation test.

RESULTS

Fifty-two eyes of 28 diabetic patients and 28 eyes of 16 healthy controls were enrolled. Type I diabetes patients had a longer disease duration than type II (30.3 ± 10.3 vs. 12.3 ± 9.7 years). The mean superficial capillary plexus (SCP) of the FAZ area was 0.27 ± 0.1, 0.36 ± 0.14, and 0.27 ± 0.12 mm², for the type I, type II, and controls (p = 0.0058) and was significantly larger in type II diabetics (p < 0.05). The mean DCP (deep capillary plexus) FAZ was significantly larger in type II diabetics vs. controls (0.67 ± 0.2 and 0.52 ± 0.16 mm² respectively) (p < 0.05). Both type I and type II SCP capillary density were significantly lower than the controls (p < 0.05, p < 0.005), and DCP capillary density was significantly lower in type II vs. controls (p < 0.005).

CONCLUSIONS

Type I patients showed fewer changes in the FAZ than the type II group, although their duration of diabetes was longer. Larger studies are needed to better analyze the differences between type I and type II diabetics.

Optical coherence tomography angiography findings of type 1 diabetic patients with diabetic retinopathy, in comparison with type 2 patients

PURPOSE

To compare optical coherence tomography angiography (OCT-A) parameters between type 1 and type 2 diabetic patients with diabetic retinopathy (DR).

METHODS

A total of 70 patients with type 1 diabetes and 70 with type 2 diabetes were retrospectively analyzed. DR was graded as no DR, mild nonproliferative DR (NPDR), moderate NPDR, severe NPDR, and proliferative DR (PDR). Using OCT-A, the foveal avascular zone (FAZ) area (mm²) and vascular density (VD) (%) were calculated in the superficial capillary plexus (SCP) and deep capillary plexus (DCP).

RESULTS

In both type 1 and 2 diabetes patients, the FAZ area (mm²) in both capillary plexuses (CP) increased with DR progression, whereas the VD (%) progressively decreased. The changes in the FAZ area and the VD were significantly greater in the DCP than in the SCP in both types of diabetes patients(p < 0.001). In the analysis of decreasing slope of the VD in the DCP, attenuation was not significant until severe NPDR stage but then abruptly decreased when it progressed to PDR stage in type 1 diabetes. In type 2 diabetes, the DCP VD decreased gradually as DR stage progressed.

CONCLUSIONS

As DR progression, the increasing in FAZ area and the decreasing in VD are more severe in the DCP than in the SCP in both types of diabetes. In type 1 diabetes eyes, they were remained in relatively healthy until it gets to the advanced stage of DR, while the gradual deterioration of FAZ area and VD was found from the early stage to the advanced stage of DR in type 2 diabetes.

Foveal microvasculature features of surgically closed macular hole using optical coherence tomography angiography

Background

To describe the features of foveal microvasculature using optical coherence tomography angiography (OCTA) and to determine the related clinical factors in eyes with surgically closed macular hole (MH).

Methods

A retrospective case series of 18 patients with unilateral MH was reviewed. The patients maintained complete hole closure after vitrectomy with inner limiting membrane (ILM) peeling for at least 12 months. The healthy fellow eyes were studied as controls. The foveal microvasculature of both eyes was examined by OCTA. The area of the foveal avascular zone (FAZ) and the vascular density (VD) ratio in the superficial and deep capillary plexuses (SCP and DCP) were determined after surgery. Several clinical factors including age, stage and dimensions of MH, papillofoveal distance, the extent of nasal displacement of the fovea after surgery, postoperative central foveal thickness, and outer-retina integrity were evaluated to determine any relationships with the OCTA parameters.

Results

The mean FAZ area in both the SCP and DCP (0.29 ± 0.11 mm² and 0.39 ± 0.14 mm²) was significantly smaller than those of the controls (0.45 ± 0.14 mm² and 0.62 ± 0.22 mm²) (p = 0.001 and <0.001, respectively). The mean VD ratio in the SCP (0.270 ± 0.349) was similar to that of the controls (0.321 ± 0.189) (p = 0.231); however, that in the DCP (0.321 ± 0.189) was significantly lower than that of the controls (0.331 ± 0.119) (p = 0.025). Only the extent of nasal displacement of the fovea was correlated with the DCP FAZ-area difference values between the study group and the controls (correlation coefficient = 0.577; p = 0.012).

Conclusions

After successful MH surgery, the FAZ area in both the SCP and DCP was smaller and the VD ratio of the DCP was lower, suggesting a possible DCP vulnerability to tractional stress. As the FAZ area of the DCP in closed-MH eyes became smaller than that in the controls, the fovea was less displaced toward the optic disc, possibly reflecting a lack of retinal redundancy caused by horizontal stretching accompanied by foveal displacement.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0607-z) contains supplementary material, which is available to authorized users.

Diametric measurement of foveal avascular zone in healthy young adults using optical coherence tomography angiography

BACKGROUND

The objective of this study is to measure the diameter size of foveal avascular zone (FAZ) in both eyes of healthy young adults using optical coherence tomography (OCT) angiography.

METHODS

A cross sectional study to measure the foveal avascular zone in healthy young adults. Subjects underwent OCT angiography using Zeiss AngioPlex OCT angiography in both eyes.

RESULTS

30 eyes of 15 healthy young adults were evaluated. The mean horizontal FAZ diameter of superficial vascular plexus was 661.166 ± 119.99 microns and mean vertical FAZ diameter was 660.033 ± 96.169 microns (P = 0.9442). The mean horizontal FAZ diameter of deep vascular plexus was 1011.2 ± 154.526 microns and the mean vertical FAZ diameter of deep vascular plexus was 818.033 ± 102.108 microns. There was no difference between the contralateral eyes of subjects in FAZ diameter of both superficial and deep capillary plexuses.

CONCLUSION

The mean diametric size of FAZ in superficial capillary plexus is 660.599 ± 0.801 microns and deep capillary plexus is 914.616 ± 136.589 microns. There was no significant difference with the contralateral eyes.