Neovascularization In Retinopathy Of Prematurity Research Articles

Phlebotomy-induced anemia reduces oxygen-induced retinopathy severity and dampens retinal developmental transcriptomic pathways in rats.

Phlebotomy-induced-anemia (PIA), which induces tissue hypoxia and angiogenesis, occurs universally among infants at risk for severe retinopathy of prematurity (ROP). We hypothesized that PIA exacerbates pathologic retinal neovascularization in ROP. We induced PIA to a hematocrit of 18% among rats undergoing the established 50/10 oxygen-induced retinopathy (OIR) model. Rats were euthanized at P15 and P20, during the avascular and neovascular phases of OIR, respectively. Retinal vascular morphometry, cytokine/chemokine concentrations, transcriptomes, and mRNA expression of angiogenic and iron-deficiency markers were compared to non-PIA controls. In OIR, PIA decreased percent avascular area at P15 by 35%, percent neovascular area at P20 by 42%, and select pro-inflammatory cytokine/chemokine concentrations at both time points. At P20, PIA increased mRNA expression of angiopoietin 2/ vascular endothelial growth factor-A 2-fold and transferrin and transferrin receptor 5-fold. RNA sequencing showed dampened pathways of angiogenesis, inflammation, and neural development in anemic OIR females. Contrary to our hypothesis, PIA decreased OIR severity and retinal cytokine and chemokine levels and dampened transcriptomic pathways central to retinal vascular and neural development in neonatal rats. These data suggest PIA provides a protective effect from OIR. Further investigation into the functional effect of these molecular changes is warranted. This is the first preclinical study to investigate the impact of neonatal anemia on oxygen-induced retinopathy (OIR) outcomes. This study adds to the literature that anemia decreases neovascularization, decreases cytokine and chemokine levels, and dampens angiogenic and neural transcriptomic pathways in the rat 50/10 OIR model. The study identifies a sex-specific transcriptomic response to anemia in the 50/10 OIR model, with females primarily impacted.

Timed topical dexamethasone eye drops improve mitochondrial function to prevent severe retinopathy of prematurity

Pathological neovascularization in retinopathy of prematurity (ROP) can cause visual impairment in preterm infants. Current ROP treatments which are not preventative and only address late neovascular ROP, are costly and can lead to severe complications. We showed that topical 0.1% dexamethasone eye drops administered prior to peak neovessel formation prevented neovascularization in five extremely preterm infants at high risk for ROP and suppressed neovascularization by 30% in mouse oxygen-induced retinopathy (OIR) modeling ROP. In contrast, in OIR, topical dexamethasone treatment before any neovessel formation had limited efficacy in preventing later neovascularization, while treatment after peak neovessel formation had a non-statistically significant trend to exacerbating disease. Optimally timed topical dexamethasone suppression of neovascularization in OIR was associated with increased retinal mitochondrial gene expression and decreased inflammatory marker expression, predominantly found in immune cells. Blocking mitochondrial ATP synthetase reversed the inhibitory effect of dexamethasone on neovascularization in OIR. This study provides new insights into topical steroid effects in retinal neovascularization and into mitochondrial function in phase II ROP, and suggests a simple clinical approach to prevent severe ROP.

Timed topical dexamethasone eye drops improve mitochondrial function to prevent severe retinopathy of prematurity.

Pathological neovascularization in retinopathy of prematurity (ROP) can cause visual impairment in preterm infants. Current ROP treatments which are not preventative and only address late neovascular ROP, are costly and can lead to severe complications. We showed that topical 0.1% dexamethasone eye drops administered prior to peak neovessel formation prevented neovascularization in five extremely preterm infants at high risk for ROP and suppressed neovascularization by 30% in mouse oxygen-induced retinopathy (OIR) modeling ROP. In contrast, in OIR, topical dexamethasone treatment before any neovessel formation had limited efficacy in preventing later neovascularization, while treatment after peak neovessel formation had a non-statistically significant trend to exacerbating disease. Optimally timed topical dexamethasone suppression of neovascularization in OIR was associated with increased retinal mitochondrial gene expression and decreased inflammatory marker expression, predominantly found in immune cells. Blocking mitochondrial ATP synthetase reversed the inhibitory effect of dexamethasone on neovascularization in OIR. This study provides new insights into topical steroid effects in retinal neovascularization and into mitochondrial function in phase II ROP, and suggests a simple clinical approach to prevent severe ROP.

Isolated Retinal Neovascularization in Retinopathy of Prematurity: Clinical Associations and Prognostic Implications

Isolated retinal neovascularization (IRNV) is a common finding in patients with stage 2 and 3 retinopathy of prematurity (ROP). This study aimed to further classify the clinical course and significance of these lesions (previously described as "popcorn" based on clinical appearance) in patients with ROP as visualized with ultrawidefield OCT (UWF-OCT). Single center, retrospective case series. Images were collected from 136 babies in the Oregon Health and Science University neonatal intensive care unit. A prototype UWF-OCT device captured en face scans (>140°), which were reviewed for the presence of IRNV along with standard zone, stage, and plus classification. In a cross-sectional analysis we compared demographics and the clinical course of eyes with and without IRNV. Longitudinally, we compared ROP severity using a clinician-assigned vascular severity score (VSS) and compared the risk of progression among eyes with and without IRNV using multivariable logistic regression. Differences in clinical demographics and disease progression between patients with and without IRNV. Of the 136 patients, 60 developed stage 2 or worse ROP during their disease course, 22 of whom had IRNV visualized on UWF-OCT (37%). On average, patients with IRNV had lower birth weights (BWs) (660.1 vs. 916.8 g, P= 0.001), gestational age (GA) (24.9 vs. 26.1 weeks, P= 0.01), and were more likely to present with ROP in zone I (63.4% vs. 15.8%, P < 0.001). They were also more likely to progress to stage 3 (68.2% vs. 13.2%, P < 0.001) and receive treatment (54.5% vs. 15.8%, P= 0.002). Eyes with IRNV had a higher peak VSS (5.61 vs. 3.73, P < 0.001) and averaged a higher VSS throughout their disease course. On multivariable logistic regression, IRNV was independently associated with progression to stage 3 (P= 0.02) and requiring treatment (P= 0.03), controlling for GA, BW, and initial zone 1 disease. In this single center study, we found that IRNV occurs in higher risk babies and was an independent risk factor for ROP progression and treatment. These findings may have implications for OCT-based ROP classifications in the future. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Efficacy of Anti-VEGF in Treatment of Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a vasoproliferative retinal disorder that affects premature infants. Vascular endothelial growth factor (VEGF) has been implicated in the pathogenesis of ROP. Anti-VEGF agents can potentially inhibit abnormal vessel growth in ROP. This study aimed to evaluate the efficacy of anti-VEGF (bevacizumab) in treatment of ROP. A prospective study was conducted on 75 patients including 70 adults and 5 ROP babies who received intravitreal injection of bevacizumab (Avastin). Distant visual acuity, slit lamp examination, indirect ophthalmoscopy and optical coherence tomography (OCT) were assessed at baseline, immediate, 1 week and 4 weeks post injection. Statistically significant improvement was observed in distant visual acuity and reduction in macular thickness after Avastin injection. At 4 weeks, best corrected visual acuity of 6/6 was attained by 15 adults and 3 ROP babies. OCT revealed decreased macular edema with mean reduction of 115.29μm. ROP subjects showed greater visual gain (mean acuity improvement - 2.4 lines) as compared to adults (mean acuity improvement - 1.52 lines). Significant correlation was found between better visual acuity and macular thickness less than 300μm. Intravitreal Avastin resulted in rapid regression of neovascularization in ROP. No ocular or systemic complications were observed. Single injection controlled disease progression in majority of cases. Anti-VEGF agents can be considered as primary modality for treating type 1 ROP due to their safety, efficacy and long-term benefits. Larger studies are required to establish optimal dosage and long-term effects.

A pilot optical coherence tomography angiography classification of retinal neovascularization in retinopathy of prematurity

Extraretinal neovascularization is a hallmark of treatment-requiring retinopathy of prematurity (ROP). Optical coherence tomography angiography (OCTA) offers vascular flow and depth information not available from indirect ophthalmoscopy and structural OCT, but OCTA is only commercially available as a tabletop device. In this study, we used an investigational handheld OCTA device to study the vascular flow in and around retinal neovascularization in seven preterm infants with treatment-requiring ROP and contrasted them to images of vascular flow in six infants of similar age without neovascular ROP. We showed stages of retinal neovascularization visible in preterm infants from 32 to 47 weeks postmenstrual age: Intraretinal neovascularization did not break through the internal limiting membrane; Subclinical neovascular buds arose from retinal vasculature with active flow through the internal limiting membrane; Flat neovascularization in aggressive ROP assumed a low-lying configuration compared to elevated extraretinal neovascular plaques; Regressed neovascularization following treatment exhibited decreased vascular flow within the preretinal tissue, but flow persisted in segments of retinal vessels elevated from their original intraretinal location. These findings enable a pilot classification of retinal neovascularization in eyes with ROP using OCTA, and may be helpful in detailed monitoring of disease progression, treatment response and predicting reactivation.

Expression of Concern: Astragalus root extract inhibits retinal cell apoptosis and repairs damaged retinal neovascularization in retinopathy of prematurity

Expression of Concern: Astragalus root extract inhibits retinal cell apoptosis and repairs damaged retinal neovascularization in retinopathy of prematurity

Pathophysiology of retinopathy of prematurity.

Retinopathy of prematurity (ROP) is a vasoproliferative disease occurring in premature infants that affects the blood vessels of the developing retina. ROP results in the development of vascular shunts, neovascularization, and in its most severe form tractional retinal detachment. The development of retinal vascular shunts and neovascularization in ROP is related to local ischemia in the immature and incompletely vascularized retina. Understanding the pathophysiology of ROP helps physicians both in the prevention and treatment of ROP and will be discussed in this review article. The role of oxygen in the pathophysiology of ROP will be reviewed with recent studies discussed.

Myeloid cells regulate retinal neovascularization via SOCS3

Abstract Neovascularization is the leading cause of vision loss in retinopathy of prematurity (ROP). Inflammation and myeloid cells are involved in retinal angiogenesis. However, the underlying mechanisms of how myeloid cells control neovascularization in ROP remain unknown. We and others previously reported that suppressor of cytokine signaling 3 (SOCS3) is induced in retinopathy. To investigate whether myeloid cells regulate retinal angiogenesis via SOCS3 in ROP, we used myeloid lineage specific SOCS3 loss-of-function (conditional knockout, cKO) mice and gain-of-function (conditional overexpression, cOE) mice and generated ROP mouse model - mice with oxygen induced retinopathy (OIR) by exposing mice to 75% oxygen from postnatal day (P)7 to P12 for 5 days, and then returned to normal air until P17. Retinas were collected for analysis including quantification of retinal neovascularization, gene expression, immune cell profiling and single cell sequencing. Our results showed that mice with myeloid SOCS3 deficiency had a substantial increase in pathological retinal neovascularization, whereas overexpression of SOCS3 in myeloid cells prevented pathological retinal neovascularization in response to OIR. Our single-cell sequencing data showed that population of myeloid lineage cells including microglia, macrophages and neutrophils was changed in mice with OIR and controlled by SOCS3. Therefore, myeloid cells are involved in retinal neovascularization via SOCS3 in ROP. Manipulating SOCS3 expression in myeloid cells may provide a new way to cure neovascularization in retinas. Supported by grants from NIH (R01EY030140, R01EY029238) and from BrightFocus Foundation

Corrigendum: Maternally expressed gene 3 regulates retinal neovascularization in retinopathy of prematurity

[This corrects the article DOI: 10.4103/1673-5374.327358].

Maternally expressed gene 3 regulates retinal neovascularization in retinopathy of prematurity.

The mouse model of oxygen induced retinopathy is suitable for the study of various retinal neovascularization diseases, including retinopathy of prematurity. The maternally expressed gene 3 (MEG3) has been demonstrated to have an inhibitory effect on diabetic retinopathy. In this study, we investigated the role of MEG3 overexpression in oxygen-induced retinopathy in mice. The results showed that MEG3 overexpression effectively inhibited the production of retinal neovascularization in oxygen-induced retinopathy mice. It acts by down-regulating the expression of phosphoinositide 3-kinase, serine/threonine kinase, and vascular endothelial growth factor and pro-inflammatory factors. MEG3 overexpression lentivirus has a future as a new method for the clinical treatment of retinopathy of prematurity. The animal experiments were approved by the Animal Ethics Committee of Shengjing Hospital of China Medical University, China (approval No. 2016PS074K) on February 25, 2016.

Retinopathy of prematurity shows alterations in Vegfa164 isoform expression

BackgroundPathologic ocular neovascularization in retinopathy of prematurity (ROP) and other proliferative retinopathies are characterized by dysregulation of vascular endothelial growth factor-A (VEGF-A). A study of Vegfa isoform expression during oxygen-induced ischemic retinopathy (OIR) may enhance our understanding of Vegf dysregulation.MethodsFollowing induction of OIR, immunohistochemistry and polymerase chain reaction (PCR) was performed on room air (RA) and OIR mice.ResultsTotal Vegfa messenger RNA (mRNA) expression was stable in RA mice, but increased in OIR mice with a peak at postnatal day 17 (P17), before returning to RA levels. Vegfa164a expression was similar in both OIR and RA mice at P10 (Phase 1 OIR), but 2.4-fold higher in OIR mice compared to RA mice at P16 (Phase 2 OIR). At P10, Vegfa164b mRNA was similar in OIR vs RA mice, but was expressed 2.5-fold higher in OIR mice compared to RA mice at P16. At P10 and P16, Vegfr2/Vegfr1 expression was increased in OIR mice compared to RA mice. Increased activation of microglia was seen in OIR mice.ConclusionsVegfa164a, Vegfa164b, and Vegfr1 were overexpressed in OIR mice, leading to abnormal signaling and angiogenesis. Further studies of mechanisms of Vegf dysregulation may lead to novel therapies for ROP and other proliferative retinopathies.ImpactVegfa164 has two major isoforms, a proangiogenic, Vegfa164a, and an antiangiogenic, Vegfa164b, with opposing receptors, inhibitory Vegfr1, and stimulatory Vegfr2, but their role in OIR is unclear.In Phase 1 OIR, both isoforms and receptors are expressed similarly.In Phase 2 OIR, both isoforms are overexpressed, with an increased ratio of inhibitory Vegfr1.Modulation of angiogenesis by Vegf regulation enables pruning of excess angiogenesis during physiology, but results in ineffective angiogenesis during OIR. Knowledge of VEGF dysregulation may have novel therapeutic implications in the management of ROP and retinal proliferative diseases.

Effects of long non-coding RNA myocardial infarction-associated transcript on retinal neovascularization in a newborn mouse model of oxygen-induced retinopathy.

Whether long non-coding RNA myocardial infarction-associated transcript is involved in oxygen-induced retinopathy remains poorly understood. To validate this hypothesis, we established a newborn mouse model of oxygen-induced retinopathy by feeding in an oxygen concentration of 75 ± 2% from postnatal day 8 to postnatal day 12, followed by in normal air. On postnatal day 11, the mice were injected with the myocardial infarction-associated transcript siRNA plasmid via the vitreous cavity to knockdown long non-coding RNA myocardial infarction-associated transcript. Myocardial infarction-associated transcript siRNA transcription significantly inhibited myocardial infarction-associated transcript mRNA expression, reduced the phosphatidylinosital-3-kinase, phosphorylated Akt and vascular endothelial growth factor immunopositivities, protein and mRNA expression, and alleviated the pathological damage to the retina of oxygen-induced retinopathy mouse models. These findings suggest that myocardial infarction-associated transcript is likely involved in the retinal neovascularization in retinopathy of prematurity and that inhibition of myocardial infarction-associated transcript can downregulate phosphatidylinosital-3-kinase, phosphorylated Akt and vascular endothelial growth factor expression levels and inhibit neovascularization. This study was approved by the Animal Ethics Committee of Shengjing Hospital of China Medical University, China (approval No. 2016PS074K) on February 25, 2016.

Angiotensin-II as a Trigger Factor in the Development of Retinopathy of Prematurity

The multifactorial nature of the retinopathy of prematurity (ROP) pathogenesis, makes the thorough study of the mechanism of pathological retinal neovascularization actual. However recently the attention of scientists has been attracted by the participation of renin-angiotensin system (RAS) in the development of retinal vasoproliferative diseases. Purpose: to study the role of AT-II in the pathogenesis of experimental ROP (EROP) in the original model of the disease. Material and methods. To reproduce EROP Wistar rats (n = 15) were exposed to the oxygen concentration varying from 60 to 15% every 12 hours for 14 days from the first day after birth followed by room air for 7 days. Throughout the experiment, the room maintained a constant temperature (+26 °C) and light regime (12 hours a day, 12 hours a night) modes. Control rats (n = 12) were born and kept under normal oxygen content (21 %). Batches of EROP (n = 5) and control (n = 4) rats were sacrificed on 7, 14 and 21 days. All rats underwent binocular enucleation, after which every eyeball was opened on the limb, the cornea and lens were removed with the remains of a persistent vascular bag and a hyaloid artery. Retinas were isolated, homogenized and stored at -20 °C. Angiotensin-II (AT-II) in homogenates was measured using the IFA kit. Results. On the 7th day of the experiment, the level of AT-II in the retina of the experimental group rats was 0.19 ± 0.02 pg/mg protein that was significantly higher than in controls (0.12 ± 0.01 pg/mg protein). On the 14th and 21st days concentrations of AT-II in EROP and control groups had no significant difference. Conclusion. On the 7th day of the experiment, i.e. at the period corresponding to the existence of avascular retinal zones in both groups concentration of AT-II in the retinas of rats with EROP was significantly higher than in controls. This fact indicate the role of this proangiogenic factor in the induction of pathological neovascularization in ROP. Possible prognostic function of this parameter during the period before ROP manifestation has undoubted practical significance.

Hyaloid Vasculature as a Major Source of STAT3+ (Signal Transducer and Activator of Transcription 3) Myeloid Cells for Pathogenic Retinal Neovascularization in Oxygen-Induced Retinopathy.

Myeloid cells are critically involved in inflammation-induced angiogenesis, although their pathogenic role in the ischemic retina remains controversial. We hypothesize that myeloid cells contribute to pathogenic neovascularization in retinopathy of prematurity through STAT3 (signal transducer and activator of transcription 3) activation. Approach and Results: Using the mouse model of oxygen-induced retinopathy, we show that myeloid cells (CD45+IsolectinB4 [IB4]+) and particularly M2-type macrophages (CD45+ Arg1+), comprise a major source of STAT3 activation (pSTAT3) in the immature ischemic retina. Most of the pSTAT3-expressing myeloid cells concentrated at the hyaloid vasculature and their numbers were strongly correlated with the severity of pathogenic neovascular tuft formation. Pharmacological inhibition of STAT3 reduced the load of IB4+ cells in the hyaloid vasculature and significantly reduced the formation of pathogenic neovascular tufts during oxygen-induced retinopathy, leading to improved long-term visual outcomes (ie, increased retinal thickness and scotopic b-wave electroretinogram responses). Genetic deletion of SOCS3 (suppressor of cytokine signaling 3), an endogenous inhibitor of STAT3, in myeloid cells, enhanced pathological and physiological neovascularization in oxygen-induced retinopathy, indicating that myeloid-STAT3 signaling is crucial for retinal angiogenesis. Circulating myeloid cells may migrate to the immature ischemic retina through the hyaloid vasculature and contribute to retinal neovascularization via activation of STAT3. Understanding how STAT3 modulates myeloid cells for vascular repair/pathology may provide novel therapeutic options in pathogenic angiogenesis.

Effect and mechanism of the long noncoding RNA MALAT1 on retinal neovascularization in retinopathy of prematurity

AimsThe most typical pathological manifestation of retinopathy of prematurity (ROP) is Retinal neovascularization (RNV). Long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been reported to mediate angiogenesis. Our experiment aimed to research the effect and mechanism of the MALAT1 on RNV in ROP. Main methodsC57 mice was used to establish oxygen-introduced retinopathy (OIR), and divided into control, hyperoxia, hyperoxia control siRNA, and hyperoxia MALAT1 siRNA groups. Key findingsIt was shown that MALAT1 mRNA was high expressed in the retinas of OIR mice. Further studies revealed that after intravitreal injection of MALAT1 siRNA, the degree of retinopathy was significantly reduced compared with OIR group. In addition, the protein and mRNA expression levels of CCN1, AKT and VEGF were significantly decreased. This was accompanied by a decrease in inflammatory genes including IL-1β, IL-6, and TNF-α compared with the hyperoxia control siRNA mice. SignificanceThe result suggested that MALAT1 may be involved in the process of RNV in ROP and MALAT1 siRNA may be a promising agent for the treatment of ROP by inhibiting RNV.

AB038. Pathological neovascularization in retinopathy of prematurity is regulated by heme-derived iron trafficking

Background: Retinopathy of prematurity (ROP) is an eye disease of the immature newborn characterized by pathological neovascularization (NV). ROP classically arises due to changes in oxygen availability in the retina. However, other factors, such as red blood cell (RBC) transfusion, independently contribute to disease severity. Heme molecules, rich in RBC, are the primary source of endogenous iron. Heme is metabolized by heme oxygenase (HO) into biliverdin, carbon monoxide, and ferrous ions. Low iron levels stabilize hypoxia-inducible factor 1α (HIF1 α), the main transcription factor of vascular endothelial growth factor (VEGF) that drives angiogenesis. Here we investigate the role of heme metabolism in pathological NV.

Astragalus root extract inhibits retinal cell apoptosis and repairs damaged retinal neovascularization in retinopathy of prematurity

ABSTRACT Since the functions of Astragalus root extract in retinopathy remain to be unraveled, this study is performed to elucidate whether Astragalus root extract functions in retinal cell apoptosis and angiogenesis in retinopathy of prematurity (ROP). Newborn mice were selected for establishing mice models of oxygen-induced retinopathy (OIR), which were treated with high-, medium- or low-Astragalus root extract. Evans Blue (EB) was perfused to detect the blood retinal barrier. Additionally, the vascular morphology, number of endothelial cell nuclei of neovascularization, proliferation of blood vessels, ultrastructural changes were determined via a series of assays. Moreover, levels of reactive oxygen species (ROS), expression of other factors such as VEGF, PEDF, IGF-1, HIF-1α, Bax, Bcl-2, eNOS, nNOS, and iNOS were detected. Astragalus root extract was found to protect blood-retinal barrier in the OIR model mice through repairing the structure and morphology of retina, inhibiting ROS production, retinal cell apoptosis, as well as improving retinal vascular angiogenesis. Astragalus root extract was also found to decrease VEGF and HIF-1α expression, but enhance PEDF and IGF-1 expression in the OIR model mice, thereby protecting retinas in ROP. This study highlights that Astragalus root extract is able to suppress retinal cell apoptosis and repair damaged retinal neovascularization in ROP, which provides basis for ROP therapy.

The association of platelet counts with development and treatment for retinopathy of prematurity - is thrombocytopenia a risk factor?

IntroductionThrombocytes may regulate the activity of vascular endothelial growth factor (VEGF), limiting neovascularization in retinopathy of prematurity (ROP). The aim of this study was to examine the role of platelet counts, thrombocytopenia, and infections in the pathogenesis of ROP.Material and methodsThe study included 163 preterm infants diagnosed with ROP, comparing 76 patients who required treatment with 87 patients in whom ROP resolved spontaneously (control group). Further analysis concerned 52 patients in whom a first line treatment was sufficient to stop ROP progression, and 24 patients who required re-treatment.ResultsA statistically significant difference was found in the occurrence of thrombocytopenia (p = 0.015), platelet counts before the diagnosis of ROP (p = 0.008), and the presence of late-onset infection (p = 0.007). The ROC curve analysis showed that the value of platelets above 232 × 109/l may stimulate spontaneous resolution of ROP. A significant difference between patients once treated and patients that required re-treatment was found in platelet count before the diagnosis of ROP (p = 0.017), platelet count before the first intervention (p = 0.013), and the number of transfusions (p = 0.042).ConclusionsThe results of the study confirm the association between ROP development and its severity with thrombocytopenia. While there were no differences in the occurrence of thrombocytopenia right after the birth, its episode before the diagnosis of ROP seems to be significant for ROP development. The deficiency of platelets prior to a treatment intervention may be associated with necessity of re-treatment.

Three-dimensional pattern of extraretinal neovascular development in retinopathy of prematurity

The application of three-dimensional (3D) visualization techniques to evaluate the earliest visible onset of abnormal retinal vascular development in preterm infants with retinopathy of prematurity (ROP), using bedside non-contact optical coherence tomography (OCT) imaging to characterize morphology and sequential structural changes of abnormal extraretinal neovascularization. Thirty-one preterm infants undergoing routine ROP screening with written informed consent for research imaging were enrolled in this prospective observational study. We imaged the macula and temporal periphery of preterm infants using a handheld OCT system (Envisu 2300 or handheld swept-source research system). The scans obtained were segmented and, using enhanced ray casting, were converted to 3D volumes to which color filter was applied. Using colorized 3D visualization, we defined extraretinal neovascular structures as buds, bridging networks, and placoid lesions. We could longitudinally follow progression and regression of extraretinal neovascularization in stage 3 ROP after treatment in one infant over 12weeks and document the appearance of early buds, and formation of florid neovascularization. From stages 2 to 3 ROP, we observed progression from sessile buds to a complex plaque that corresponded to stage 3 ROP on clinical examination. We demonstrated regression of neovascular complexes to small pre-retinal tufts after treatment with anti-VEGF. The extension of OCT processing to include surface flattening and colorization that further improved structural analysis rendered better understanding of extraretinal tissue. Our ability to image similar areas in the same infant over multiple visits enabled us to study the evolution of these structural components and follow pathological vascular events longitudinally in development and regression after treatment. These methods can be applied to further study which are likely contribute to our understanding of the pathophysiology of neovascularization in ROP.