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

Effects of hemoglobin concentration on retinochoroidal vascular plexuses: an optical coherence tomography angiography study

PURPOSE

To evaluate retinal and choroidal microvascular structures using optical coherence tomography angiography (OCTA) in patients with anemia and polycythemia vera (PV).

METHODS

In this prospective study, 142 patients (142 eyes) were enrolled and divided into 3 groups: the anemia (n = 56), PV (n = 46), and healthy groups (n = 40, controls). For each patient, 6- × 6-mm macular angiography images were taken using an OCTA system (optovue, Inc., Fremont). For each eye analyzed, the software automatically measured vessel density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP; superior, nasal, temporal, and inferior quadrants), choriocapillaris (CC), and foveal avascular zone (FAZ).

RESULTS

The OCTA analysis revealed that the VD of the DCP was significantly decreased in the superior and inferior hemispheres of the whole area, multiple quadrants of the perifovea, and CC with a 1-mm2 flow area in the anemia group compared with the PV group (p < 0.017), but the VD of the SCP did not show any significant difference in any quadrant between the two groups (p > 0.017). When compared with the healthy group, the anemia and PV groups showed a significant difference in multiple quadrants of the parafovea and temporal quadrant of the perifovea in the VD of the SCP and CC with a 2-mm2 flow area (p < 0.017). The FAZ and non-flow area did not manifest any significant difference between the groups (p > 0.017). The hemoglobin concentrations in the anemia, PV, and healthy groups were 8.11 ± 1.33, 17.5 ± 1.2, and 15.6 ± 0.73 g/dL, respectively, indicating statistically significant differences between the groups (p < 0.001).

CONCLUSION

In this study, quantitative OCTA analysis revealed a higher tendency for retinal and choroidal microvascular morphological changes in patients with anemia and PV. The outcomes of the current investigation can provide new insights into the retinal and choroidal pathophysiologies found in patients with hemoglobin abnormalities.

Optical coherence tomography angiography for the characterisation of retinal microvasculature alterations in pregnant patients with anaemia: a nested case‒control study

AIMS

To characterise retinal microvascular alterations in the eyes of pregnant patients with anaemia (PA) and to compare the alterations with those in healthy controls (HC) using optical coherence tomography angiography (OCTA).

METHODS

This nested case‒control study included singleton PA and HC from the Eye Health in Pregnancy Study. Fovea avascular zone (FAZ) metrics, perfusion density (PD) in the superficial capillary plexus, deep capillary plexus and flow deficit (FD) density in the choriocapillaris (CC) were quantified using FIJI software. Linear regressions were conducted to evaluate the differences in OCTA metrics between PA and HC. Subgroup analyses were performed based on comparisons between PA diagnosed in the early or late trimester and HC.

RESULTS

In total, 99 eyes of 99 PA and 184 eyes of 184 HC were analysed. PA had a significantly reduced FAZ perimeter (β coefficient=-0.310, p<0.001), area (β coefficient=-0.121, p=0.001) and increased circularity (β coefficient=0.037, p<0.001) compared with HC. Furthermore, higher PD in the central (β coefficient=0.327, p=0.001) and outer (β coefficient=0.349, p=0.007) regions were observed in PA. PA diagnosed in the first trimester had more extensive central FD (β coefficient=4.199, p=0.003) in the CC, indicating impaired perfusion in the CC.

CONCLUSION

It was found that anaemia during pregnancy was associated with macular microvascular abnormalities, which differed in PA as pregnancy progressed. The results suggest that quantitative OCTA metrics may be useful for risk evaluation before clinical diagnosis.

TRIAL REGISTRATION NUMBERS

2021KYPJ098 and ChiCTR2100049850.

Does thalassemia truly cause microvascular changes without us noticing? An optical coherence tomography angiography study of the children with beta-thalassemia

PURPOSE

It was aimed to evaluate the retinochoroidal microvascular alterations of pediatric beta-thalassemia patients and investigate the effect of blood transfusion on perfusion among transfusion-dependent thalassemia (TDT), by means of optical coherence tomography angiography (OCTA).

METHODS

In this multicentered, prospective, cross-sectional study, 56 TDT, 14 non-TDT (NTDT), and 63 healthy children were evaluated. The vessel density (VD) in superficial capillary plexus (SCP), deep capillary plexus, radial peripapillary capillary network, choriocapillaris, and the foveal avascular zone area (FAZ) were evaluated by OCTA. Before and after transfusion values ​​of the TDT group were compared, and correlations were made with blood values ​​and iron accumulation.

RESULTS

Foveal and parafoveal zones were significantly thinner among TDT patients, with larger FAZ area. Macula VD of SCP and ppVD was lowest in NTDT group. In the TDT group, a decrease in retinal nerve fiber thickness and ppVD values was detected ​​after transfusion. A negative significant relationship was found between both hemoglobin (Hb), hematocrit (Htc), and ppVD.

CONCLUSIONS

OCTA provides a better insight into retinal and choriocapillaris vascular impairment influenced by tissue hypoxia and oxidative stress in different clinical phenotypes of beta-thalassemia.

Diagnosing Systemic Disorders with AI Algorithms Based on Ocular Images

The advent of artificial intelligence (AI), especially the state-of-the-art deep learning frameworks, has begun a silent revolution in all medical subfields, including ophthalmology. Due to their specific microvascular and neural structures, the eyes are anatomically associated with the rest of the body. Hence, ocular image-based AI technology may be a useful alternative or additional screening strategy for systemic diseases, especially where resources are scarce. This review summarizes the current applications of AI related to the prediction of systemic diseases from multimodal ocular images, including cardiovascular diseases, dementia, chronic kidney diseases, and anemia. Finally, we also discuss the current predicaments and future directions of these applications.

The Role of Optical Coherence Tomography Angiography in Optic Nerve Head Edema: A Narrative Review

Optic nerve head (ONH) edema is a clinical manifestation of many ocular and systemic disorders. Ocular and central nervous system imaging has been used to differentiate the underlying cause of ONH edema and monitor the disease course. ONH vessel abnormalities are among the earliest signs of impaired axonal transportation. Optical coherence tomography angiography (OCTA) is a noninvasive method for imaging ONH and peripapillary vessels and has been used extensively for studying vascular changes in ONH disorders, including ONH edema. In this narrative review, we describe OCTA findings of the most common causes of ONH edema and its differential diagnoses including ONH drusen.

Quantitative vessel density analysis of macular and peripapillary areas by optical coherence tomography angiography in adults with primary nephrotic syndrome

PURPOSE

To compare the microvascular parameters of macular and peripapillary areas in adults with primary nephrotic syndrome (PNS) and healthy controls (HCs).

METHODS

In this cross-sectional study, optical coherence tomography angiography (OCTA) was used to evaluate the changes in retinal microvascular in 37 adult patients with PNS and 30 HCs in this study. All subjects underwent OCTA for measuring vascular density (VD), perfusion density (PD), and foveal avascular zone (FAZ) in the superficial capillary plexus (SCP) and optical coherence tomography (OCT) for measuring central macular thickness (CMT) and retinal nerve fiber layer (RNFL) thickness. The following clinical data of the PNS group were collected: hemoglobin, platelet, total protein, albumin, prealbumin, creatinine, urea nitrogen, glomerular filtration rate, blood lipid, urinary protein, urine microalbumin, urine microalbumin/creatinine, 24-h urine volume, and 24-h urine protein quantification. The OCTA data were compared between patients with PNS and HCs, and the correlation between the OCTA data and clinical data was analyzed in the PNS group.

RESULTS

VD and PD in the macular area of the PNS group were significantly lower than those in the HC group (VD: 17.025 ± 2.229 vs. 18.290 ± 0.721, P = 0.001; PD: 0.417 ± 0.058 vs. 0.450 ± 0.019, P = 0.003). No significant differences in the FAZ area and perioptic disc microvascular parameters were observed between the two groups, and patients in the PNS group showed consistent changes in the left and right eyes. VD and PD in the central macular area were positively correlated with plasma prealbumin level (VD: ρ = 0.541, P = 0.001; PD: ρ = 0.562, P < 0.001) and negatively correlated with urinary protein level (VD: ρ = -0.579, P < 0.001; PD: ρ = -0.596, P < 0.001).

CONCLUSIONS

In adult patients with PNS, the decrease in VD and PD was mainly occurred in the macular area. Partly vascular density of the macular area was positively correlated with plasma prealbumin level and negatively correlated with urinary protein level. OCTA provides a convenient, non-invasive and effective method for evaluating and monitoring retinal microcirculation damage in patients with PNS.

Deep-Learning-Based Hemoglobin Concentration Prediction and Anemia Screening Using Ultra-Wide Field Fundus Images

Background: Anemia is the most common hematological disorder. The purpose of this study was to establish and validate a deep-learning model to predict Hgb concentrations and screen anemia using ultra-wide-field (UWF) fundus images.

Methods: The study was conducted at Peking Union Medical College Hospital. Optos color images taken between January 2017 and June 2021 were screened for building the dataset. ASModel_UWF using UWF images was developed. Mean absolute error (MAE) and area under the receiver operating characteristics curve (AUC) were used to evaluate its performance. Saliency maps were generated to make the visual explanation of the model.

Results: ASModel_UWF acquired the MAE of the prediction task of 0.83 g/dl (95%CI: 0.81–0.85 g/dl) and the AUC of the screening task of 0.93 (95%CI: 0.92–0.95). Compared with other screening approaches, it achieved the best performance of AUC and sensitivity when the test dataset size was larger than 1000. The model tended to focus on the area around the optic disc, retinal vessels, and some regions located at the peripheral area of the retina, which were undetected by non-UWF imaging.

Conclusion: The deep-learning model ASModel_UWF could both predict Hgb concentration and screen anemia in a non-invasive and accurate way with high efficiency.

Detection of Systemic Diseases From Ocular Images Using Artificial Intelligence: A Systematic Review

PURPOSE

Despite the huge investment in health care, there is still a lack of precise and easily accessible screening systems. With proven associations to many systemic diseases, the eye could potentially provide a credible perspective as a novel screening tool. This systematic review aims to summarize the current applications of ocular image-based artificial intelligence on the detection of systemic diseases and suggest future trends for systemic disease screening.

METHODS

A systematic search was conducted on September 1, 2021, using 3 databases-PubMed, Google Scholar, and Web of Science library. Date restrictions were not imposed and search terms covering ocular images, systemic diseases, and artificial intelligence aspects were used.

RESULTS

Thirty-three papers were included in this systematic review. A spectrum of target diseases was observed, and this included but was not limited to cardio-cerebrovascular diseases, central nervous system diseases, renal dysfunctions, and hepatological diseases. Additionally, one- third of the papers included risk factor predictions for the respective systemic diseases.

CONCLUSIONS

Ocular image - based artificial intelligence possesses potential diagnostic power to screen various systemic diseases and has also demonstrated the ability to detect Alzheimer and chronic kidney diseases at early stages. Further research is needed to validate these models for real-world implementation.

Macular Structure and Microvasculature Changes in AIDS-Related Cytomegalovirus Retinitis Using Optical Coherence Tomography Angiography

Background: Cytomegalovirus retinitis (CMVR) is a crucial blind-causing disease of AIDS-related ocular opportunistic infection. The CMVR lesions produced retinal necrosis. It is not entirely clear whether CMVR eyes without macular-involved necrotic lesions may have subtle macular damage. In this study, we conducted a cross-sectional study using optical coherence tomography angiography (OCTA) to evaluate macular microvasculature and structure in eyes with AIDS-related CMVR.

Methods: Acquired immune deficiency syndrome (AIDS)-related CMVR patients (active and inactive CMVR) and healthy controls treated in the Department of Ophthalmology, Beijing Youan Hospital, Capital Medical University between August 25, 2019, and October 18, 2019, were recruited. All OCTA parameters, including the foveal avascular zone (FAZ), retinal vessel density (VD), choroidal vascularity index (CVI), retinal thickness, and choroidal thickness, were compared between groups after the signal strength was corrected.

Results: Signal strength in the 3 × 3 and 6 × 6 mm scan patterns was significantly weaker in the inactive CMVR group than in the control group (both p < 0.001). After adjusting for signal strength, heterogeneity in the central fovea and parafoveal quadrants was present with a shift toward lower macular chorioretinal vasculature, decreased full choroidal thickness, and thicker retinal thickness in the active and inactive CMVR groups. The retinal nerve fiber layer (RNFL) and inner nuclear layer (INL) were significantly thicker in the active and inactive CMVR groups than in the control group (all p < 0.05). For photoreceptor-retinal pigment epithelium (PR-RPE) thickness, no significant differences were found in any quadrant between groups. Foveal avascular zone areas were not significantly different among the three groups (p = 0.053).

Conclusions: Subtle macular structure and microvasculature damage still existed in CMVR eyes without macular-involved necrotic lesions. The results of our study are helpful for a deep understanding of the damage caused by CMVR.

Choroidal and retinal thickness variations in anaemia and anaemic retinopathy

Anemia is the most common hematological disorder noted in the people of the Indian subcontinent. Hemodynamic changes following anemia on the retina and choroid are not frequently studied. The aim of the study was to analyse the subfoveal retinal (CRT) and choroidal (SFCT) thickness changes in patients with anemia. In this retrospective, comparative study, patients who were diagnosed with primary anemia and had a fundus examination by a retinal specialist were included. Patients were divided into 3 groups: Group 1: Patients with anemic retinopathy; Group 2: Patients with anemia without retinopathy; Group 3: Normal healthy controls. One hundred and ninety-seven eyes of 197 subjects (group 1 - 38 eyes, group 2 - 90 eyes; group 3 - 69 eyes) met the inclusion criteria. Mean CRT was 269 ± 117µm, 258 ± 99.7µm and 201 ± 19.2µm and SFCT was 303 ± 68.4µm, 303 ± 50.1µm and 275 ± 38.9µm in groups 1, 2 and 3 respectively. Low haemoglobin corelated negatively with retinal (r = -0.362; p = <0.001) and choroidal (r = -0.294; p = <0.001) thickening and reduced visual acuity (r = -0.157; p = 0.03). In conclusion, patients with anemia have a thicker retina and choroid compared to normal healthy controls.

The Impact of Chronic Heart Failure on Retinal Vessel Density Assessed by Optical Coherence Tomography Angiography in Children with Dilated Cardiomyopathy

(1) Introduction: The aim of this study is to assess retinal vessel density (VD) in the superficial capillary plexus layer (SP) and deep capillary plexus layer (DP) in children with chronic heart failure (CHF) in the course of dilated cardiomyopathy (DCM) using optical coherence tomography angiography (OCTA). (2) Methods: Thirty children with CHF due to DCM lasting more than six months, with an enlarged left ventricle and impaired left ventricular systolic function (left ventricular ejection fraction (LVEF) ≤ 55%), were enrolled to have both their eyes assessed for this study. Mean age of the children was 9.9 ± 3.57 years. The control group consisted of an additional 30 children without CHF (mean age 11.27 ± 3.33 years) matched for age and gender against the study group. All participants underwent transthoracic echocardiography to measure LVEF using Simpson method. Blood serum was tested for N-terminal-pro-brain natriuretic peptide (NT-proBNP) marker value. All children underwent OCTA with evaluation of the foveal avascular zone (FAZ), whole superficial vessel density (wsVD), foveal superficial vessel density (fsVD), parafoveal superficial vessel density (psVD), whole deep vessel density (wdVD), foveal deep vessel density (fdVD), parafoveal deep vessel density (pdVD), whole thickness (WT), foveal thickness (FT), and parafoveal thickness (PFT). (3) Results: Retinal VD in SP was significantly lower in children with CHF as compared to the controls. The following SP parameters in the study group were statistically significantly lower than these same measurements for the control group. Details, with study group findings quantified first, include wsVD (46.2% vs. 49.83%, p < 0.05), fsVD (18.07% vs. 24.15%, p < 0.05), and psVD (49.24% vs. 52.51%, p < 0.05). The WT (311.03 micrometers (μm) vs. 323.55 μm, p < 0.05), FT (244.57 μm vs. 256.98 μm, p < 0.05), and PFT (320.63 μm vs. 332.02 μm, p < 0.05). No significant differences in DP retinal VD were found between the two groups. No statistically significant differences in the FAZ were found. The fsVD and FT were correlated with biometry and the age of the study participants. There was a correlation between FAZ and FT (p < 0.001). There were no correlations between retinal VD in both plexuses and refractive error, sex, NT-proBNP, and LVEF. (4) Conclusions: In children with CHF in the course of DCM as compared to the control group, significantly decreased retinal VD in SP was observed. The results of our study indicate that measurements of the OCTA may be a useful diagnostic method in children with chronic heart failure, but it is necessary to conduct further studies in larger groups of participants and long-term observation of these patients.

Retinochoroidal vascular plexuses in patients with iron deficiency anaemia

Clinical relevance: Optical coherence tomography angiography (OCT-A) may enable the identification of alteration in the retinochoroidal microvasculature in patients with iron deficiency anaemia.Background: To investigate the presence of macular microvascular alterations in females with IDA by using OCT-A.Methods: This is a cross-sectional comparative study. Forty patients with IDA and 35 age-matched healthy women underwent a complete ophthalmologic examination and OCT-A imaging. Foveal avascular zone parameters and the vessel density in the superficial (SCP) and deep capillary plexus (DCP) were calculated using automated software. All measurements were compared between groups. Correlations between the OCT-A metrics and haematological laboratory parameters were evaluated.Results: Compared to healthy subjects, IDA patients revealed significantly decreased vessel density of the SCP in all parafoveal quadrants (p < 0.05). In contrast, vessel density analysis in DCP has shown no statistically significant difference in all parafoveal quadrants (p > 0.05). Although foveal vessel density in both SCP and DCP were higher in the IDA group, only the foveal vessel density in DCP was significantly higher than controls (p = 0.001). The mean values of the foveal avascular zone area and perimeter and choriocapillaris flow area were significantly lower in the IDA group (p < 0.05). The parafoveal vessel density in SCP, foveal avascular zone area, and choriocapillaris flow area were positively correlated with haematological parameters including haemoglobin, haematocrit, mean corpuscular haemoglobin, and mean corpuscular volume (p < 0.01).Conclusion: Patients with IDA had decreased parafoveal vessel density in the SCP, but not the DCP. Foveal avascular zone metrics and choriocapillaris flow area measurements were significantly lower in IDA.

Evaluation of radial peripapillary capillary density in patients with newly diagnosed iron deficiency anemia

PURPOSE

To investigate the effects of iron deficiency anemia (IDA) on radial peripapillary capillary vessel density (RPCvd) and retinal nerve fiber layer (RNFL) thickness.

METHODS

Forty patients with IDA, and 46 healthy participants, were enrolled in this study. Optical coherence tomography angiography was used to determine RNFL thickness and RPCvd measurements. In addition, hemoglobin (Hb), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and ferritin laboratory values were evaluated.

RESULTS

Analysis of retinal regions (whole images, peripapillary, superior-hemi, inferior-hemi, inferior-nasal, inferior-temporal, temporal-inferior, temporal-superior, superior-nasal) showed that RPCvd values were significantly lower in patients with IDA compared to the control group values (p < 0.05 for all). However, there were no significant differences in RNFL thickness values between the IDA patient group and the control group (p > 0.05 for all). In addition, there were significant positive correlations between RPCvd values and hematological values for Hb, HCT, MCV, MCH, MCHC, and ferritin.

CONCLUSION

It is important to identify changes in retinal vascularity to prevent possible ocular problems in patients with IDA. Specifically, the significant positive correlations between RPCvd values and hematological values suggest that anemia treatment is important for optic nerve perfusion.