Diabetic Retinal Neovascularization Research Articles

Reassessment of arterial versus venous perfusion of diabetic retinal neovascularization using ultrawide-field fluorescein angiography.

The purpose of this study was to assess whether diabetic NV is perfused by the arterial or the venous circulation. This is a retrospective, consecutive case series evaluating patients with proliferative diabetic retinopathy (PDR) imaged with ultrawide-field (UWF) fluorescein angiography (FA). Areas of neovascularization elsewhere (NVE) and neovascularization of the disc (NVD) were assessed. Perfusion was defined as arterial, arteriovenous, or venous if the area of diabetic neovascularization (NV) began to hyperfluoresce either prior, during, or after laminar venous flow, respectively. A total of 180 eyes from 176 patients with 928 NV were identified (830 NVE, 98 NVD). Of those, 5.1% of NVE were classified as arterial and 58.2% of NVD were classified as arterial. The remaining NV were classified as arteriovenous except for a small subset (6.1%) which were indeterminate. None of the NV were classified as venous. Noteworthy examples demonstrated NV that nearly fully perfused prior to any detectable fluorescence within nearby veins as well as clear shunting of blood from a feeding artery to a draining vein. UWF FA images suggest that some NV is perfused by retinal arteries. This may be useful in devising strategies for early detection and treatment of NV precursors. What is known • Diabetic retinal neovascularization has long been thought to be perfused by the retinal venous circulation. • Vascular endothelial growth factor has been shown to play key roles in both angiogenesis and arteriogenesis. What is new • Ultrawide-field fluorescein angiography demonstrates that at least some diabetic neovascularization is perfused by the retinal arterial circulation. • This supports the hypothesis that diabetic neovascularization may arise from arterially-perfused intraretinal microvascular abnormalities in the capillary bed.

Therapeutic effect of ultra-long-lasting human C-peptide delivery against hyperglycemia-induced neovascularization in diabetic retinopathy.

Rationale: Neovascularization is a hallmark of the late stages of diabetic retinopathy (DR) leading to blindness. The current anti-DR drugs have clinical disadvantages including short circulation half-lives and the need for frequent intraocular administration. New therapies with long-lasting drug release and minimal side effects are therefore needed. We explored a novel function and mechanism of a proinsulin C-peptide molecule with ultra-long-lasting delivery characteristics for the prevention of retinal neovascularization in proliferative diabetic retinopathy (PDR). Methods: We developed a strategy for ultra-long intraocular delivery of human C-peptide using an intravitreal depot of K9-C-peptide, a human C-peptide conjugated to a thermosensitive biopolymer, and investigated its inhibitory effect on hyperglycemia-induced retinal neovascularization using human retinal endothelial cells (HRECs) and PDR mice. Results: In HRECs, high glucose conditions induced oxidative stress and microvascular permeability, and K9-C-peptide suppressed those effects similarly to unconjugated human C-peptide. A single intravitreal injection of K9-C-peptide in mice resulted in the slow release of human C-peptide that maintained physiological levels of C-peptide in the intraocular space for at least 56 days without inducing retinal cytotoxicity. In PDR mice, intraocular K9-C-peptide attenuated diabetic retinal neovascularization by normalizing hyperglycemia-induced oxidative stress, vascular leakage, and inflammation and restoring blood-retinal barrier function and the balance between pro- and anti-angiogenic factors. Conclusions: K9-C-peptide provides ultra-long-lasting intraocular delivery of human C-peptide as an anti-angiogenic agent to attenuate retinal neovascularization in PDR.

Characterizing Flow and Structure of Diabetic Retinal Neovascularization after Intravitreal Anti-VEGF Using Optical Coherence Tomography Angiography: A Pilot Study.

Background/Aims. This study evaluates changes of flow and structure of diabetic retinal neovascularization (NV) treated with intravitreal antivascular endothelial growth factor (VEGF) agents using optical coherence tomography angiography (OCTA). With OCTA, retinal blood vessels are visualized at high resolution to separately look at flow and structure information without the need for dye injection. We introduce a new measurement method including and combining information of flow and structure. Methods. Retrospective observational case series. Patients with proliferative diabetic retinopathy (PDR) were treated with intravitreal antiVEGF injections. Retinal NV were repeatedly imaged using swept-source OCTA (Zeiss PlexElite 9000) at baseline, after initial treatment block with 3-4 monthly injections, and during a follow-up period of up to 51 weeks. Change of size and flow density of the structural and angio area of NV was assessed. Results. Nine NV in eight eyes of five patients were analyzed with a median follow-up time of 45 weeks. After the initial treatment block, en face structural area regressed, 18.7% ± 39.0% (95% CI 44.2–6.8%, p=0.26), and en face angio area regressed, 51.9% ± 29.5% (95% CI 32.6 to 71.2%, p=0.007). Flow density within the en face structural area decreased by 33% ± 19.2% (95% CI 20.5–45.5%, p=0.0077). Flow density within the en face angio area decreased by mean 17.9% ± 25.2% (95% CI 1.4–34.4%, p=0.066). In two fellow eyes, NV recurrence could be observed before the onset of vitreous bleeding in one. Conclusion. Our study introduces a new quantitative measurement for NV in PDR, combining structure and flow measurement. The structure area remained after treatment, while its flow density and angio area regressed. We propose this measurement method as a more physiological and possibly more comparable metrics.

Evaluation of the Prognostic Significance of Adipose Tissue Hormones in the Development of Diabetic Retinopathy in Patients With Type 2 Diabetes Mellitus

Relevance: There are evidences of the participation of adipose tissue hormones (ATH) in the development of diabetic microangiopathy and retinal neovascularization. The disign of methods for the mathematical evaluation of the prognosis of the development of diabetic retinopathy (DR) with the participation of ATH is an actual problem in modern diabetology. Goal: Elaboration of a mathematical model for assessing the prognostic significance of ATH to study the likelihood of developing and progressing DR in patients with type 2 diabetes mellitus (T2DM). Materials and Methods: An open observational single-center one-stage selective study was conducted. The study was approved by the Local Ethics Committee. 59 patients (187 eyes) with T2DM and DR (men and women; mean age - 58.20±0.18 years; mean T2DM duration - 9.19±0.46 years; mean HbA1C - 9.10±0.17 %), were assigned to 3 groups, based on the stage of DR (according to fundus instrumental examination), and underwent the study. The diagnostic predictive value was assessed by discriminant analysis. Models with linear combinations of the serum leptin, adiponectin and resistin, triglyceride (TG), also HbA1C, type of antidiabetic therapy (ADT) were developed, and, subsequently, formulas for classification-relevant discriminant functions were derived. ADT included metformin, either alone (type 1 ADT), or in combination with oral anti-hyperglycemic medication (type 2 ADT) or insulin therapy (type 3 ADT). The classification functions (CF) computed based on the variables found from the above developed models provided the basis for predicting the development of DR. Results: The formulas for CF from model are as follows: CF1 = 0.29 * TG + 1.55 * HbA1 + 1.81 * ADT_Type + 0.04 * Leptin + 0,34* Adiponectin + 0,91* Resistin – 13,82; CF2 = 0.05*TG + 1.36 * HbA1 + 3.01 * ADT_Type + 0.08 * Leptin + 0,35* Adiponectin + 1,01 * Resistin – 15.95. A step-by-step approach to diagnostic decision making should be used. First, blood samples are tested for serum leptin, adiponectin and resistin, TG, blood HbA1, and the patient is assigned a code for ADT_Type (1, 2 or 3). Second, CF1 and CF2 values are calculated. Finally, the two values are compared to determine which is greater. The predictive decision is made by selecting the classification function with the greater value. Thus, if CF1>CF2, the process can be stabilized at this stage given an adequate glycemic control (through compensation of carbohydrate metabolism) and body-mass control as well as patient compliance. If CF1<CF2, the pathological process may progress to the next stage or even within stage 3, and there is an urgent need to reduce BMI, and to correct the ADT and the blood lipid profile. Conclusion: Informativeness and statistical significance of model is 71.4 % and p=0.040, respectively.

Detection of neovascularisation in the vitreoretinal interface slab using widefield swept-source optical coherence tomography angiography in diabetic retinopathy

AimsTo compare the efficacy of diabetic retinal neovascularisation (NV) detection using the widefield swept-source optical coherence tomography angiography (WF SS-OCTA) vitreoretinal interface (VRI) Angio slab and SS-OCT VRI Structure slab.MethodsA...

Longitudinal Angiographic Evidence That Intraretinal Microvascular Abnormalities Can Evolve into Neovascularization

The hallmark of proliferative diabetic retinopathy (PDR) is retinal neovascularization. Tortuous intraretinal vascular segments known as intraretinal microvascular abnormalities (IRMAs) are a known risk factor for neovascularization (NV), but whether IRMA represents a biomarker or a vascular precursor lesion to NV has not been demonstrated. The purpose of this study was to determine whether IRMA may evolve directly into NV. Retrospective analysis of prospective, observational case series. Patients with treatment-naïve PDR. Patients were imaged longitudinally with fluorescein angiography (FA) and swept-source (SS) OCT angiography (OCTA) before and after panretinal photocoagulation (PRP). Presence and colocalization of IRMA and NV on serial FA and SS OCTA. Two PDR patients showed multiple NV and IRMA lesions at baseline examination. Three months after PRP, FA demonstrated profuse leakage from 3 new NV lesions in one patient and 1 new NV lesion in another patient. Multimodal imaging showed that these 4 lesions were IRMAs at baseline. Swept-source OCTA performed before PRP and 1 week, 1 month, and 3 months after PRP confirmed that the precursor IRMA lesions were intraretinal tortuous vascular lesions at baseline and that they developed into preretinal NV with contiguous intraretinal components. NV was found to develop and adhere to the posterior hyaloid even in areas of pre-existing hyaloidal detachment. Diabetic retinal NV can develop from IRMA. Early identification of IRMAs may be an accurate means of predicting progression to PDR, and frequent monitoring of IRMAs with SS OCTA may facilitate early diagnosis of PDR.

Vitreoretinal Interface Slab in OCT Angiography for Detecting Diabetic Retinal Neovascularization

To compare neovascularization identified in proliferative diabetic retinopathy (PDR) eyes by widefield swept-source (SS) OCT angiography (OCTA) using vitreoretinal interface (VRI) slab images, composed by automated and manual segmentation, with that identified by fluorescein angiography (FA). Retrospective study. Forty-two eyes of 30 treatment-naïve PDR patients who visited the outpatient clinic of the Department of Ophthalmology, Shinshu University, from June 2018 through October2019. All patients underwent comprehensive ophthalmologic examinations, including SS-OCTA and FA. Neovascularization detected by en face SS-OCTA 15× 15-mm VRI slab images and by FA in the same 15× 15-mm areas were compared in terms of number and structure. Among 100 neovascularizations detected by FA, 73 also were visualized as neovascularization in SS-OCTA VRI slab images using automated segmentation. The sensitivity of VRI slab images for detecting neovascularization was 73%. Among the remaining 27 neovascularizations detected only by FA, but not by VRI slab, 15 were intraretinal microvascular abnormalities with fluorescence leakage, 1 was a diabetic papillopathy, and 11 were flat neovascularizations on the internal limiting membrane surface that were missed because of segmentation error. Conversely, among the 98 neovascularizations detected on VRI slab images, 25 were not detected as neovascularizations by FA. They included 9 small neovascularizations that exhibited too little leakage on FA and 16 false-positive results that were the result of segmentation errors. After reconstruction of SS-OCTA VRI slab images by means of manual segmentation, the sensitivity of VRI slab images for detecting neovascularizations increased to 84%. The efficacy of SS-OCTA VRI slab images for detecting neovascularizations in PDR was comparable with that of FA. Swept-source OCTA VRI slab images may be better than FA for identifying intraretinal microvascular abnormalities and diabetic papillopathy from neovascularizations. Notably, however, FA and SS-OCTA VRI slab images demonstrated differences in identification efficacy in cases of small and flat neovascularizations. Further exploration of SS-OCTA technology is warranted to address this issue.

‘Dye-less’ angiography of diabetic retinal neovascularisation

A 61-year-old man presented with floaters in his right eye for the past 2 weeks. He had a history of poorly controlled type 2 diabetes mellitus for the past 16...

Secretogranin III: a diabetic retinopathy-selective angiogenic factor.

Secretogranin III (Scg3) is a member of the granin protein family that regulates the biogenesis of secretory granules. Scg3 was recently discovered as an angiogenic factor, expanding its functional role to extrinsic regulation. Unlike many other known angiogenic factors, the pro-angiogenic actions of Scg3 are restricted to pathological conditions. Among thousands of quantified endothelial ligands, Scg3 has the highest binding activity ratio to diabetic vs. healthy mouse retinas and lowest background binding to normal vessels. In contrast, vascular endothelial growth factor binds to and stimulates angiogenesis of both diabetic and control vasculature. Consistent with its role in pathological angiogenesis, Scg3-neutralizing antibodies alleviate retinal vascular leakage in mouse models of diabetic retinopathy and retinal neovascularization in oxygen-induced retinopathy mice. This review summarizes our current knowledge of Scg3 as a regulatory protein of secretory granules, highlights its new role as a highly disease-selective angiogenic factor, and envisions Scg3 inhibitors as "selective angiogenesis blockers" for targeted therapy.

Effects of reduced β2 glycoprotein I on high glucose‑induced cell death in HUVECs.

Reduced β2 glycoproteinI (β2GPI) has been demonstrated to exhibit a beneficial effect in diabetic atherosclerosis and retinal neovascularization. However, the effect of reduced β2GPI on vascular disorders in diabetic mellitus (DM) remains to be elucidated. The present study established a high glucose‑induced injury model using human umbilical cords veins (HUVECs) and evaluated the protective effects of reduced β2GPI against the injury. The data demonstrated that a low concentration of reduced β2GPI (0.5µM) mitigated high glucose‑induced cell loss, decreased nitric oxide (NO) production and resulted in calcium overloading. Mechanically, reduced β2GPI additionally reversed high glucose‑induced phosphatase and tensin homolog (PTEN) accumulation, decrease of protein kinase B phosphorylation and nitric oxide synthase activity, and increase of cyclooxygenase‑2 activity. It was further confirmed that PTEN inhibitor‑bpV (1µM) exhibited similar effects to those resulting from reduced β2GPI. Overall, the data revealed that reduced β2GPI exerts protective effects from glucose‑induced injury in HUVECs, potentially via decreasing PTEN levels. The present study suggests reduced β2GPI may act as a novel therapeutic strategy for the treatment of vascular disorders in DM.

Advancement of endostatin on inhibiting neoangiogenesis of diabetic retinopathy

Diabetic retinopathy (DR) is a common disease of ophthalmology, often causes irreversible decline of patients' vision, which has two features including macular oedema, diabetic retinal neovascularization.Diabetic retinal neovascularization is one of the most important reasons leading to blindness.Endostatin (ES) is one of the most effective agents inhibiting angiogenesis, whose biological function has a close relationship with its chemical construction.However, its mechanisms of treating diabetic retinal neovascularization are very complicated and remain unclear.Therefore, in this review we summarized several possible mechanisms, including regulating the expression of extracellular matrix, inhibiting the expression of pro-angiogenic factors, and regulating the signaling pathways, by which ES may inhibiting diabetic retinal neovascularization. Key words: Endostatin; Diabetic retinopathy; Ocular neovascularization; Vascular endothelial growth factor

A study on evaluation of bevacizumab in the management of diabetic retinopathy

Aims: The study stands to evaluate the usage of bevacizumab against diabetic retinal neovascularisation. Materials and Methods: The outcome measures of study include the determination of visual acuity and retinal cum macular thickness after bevacizumab administration. Twenty diabetic retinopathy patients were screened for bevacizumab administration and given either one or two doses of bevacizumab. Patient's visual acuity and optical tomography's results were analyzed to determine the vision, retinal, and macular thickness. Statistical Analysis Used: The numeric results were passed through analysis of variance, employing “Student's t-test” as posttest for statistically determining the numeric outcomes. Results: Within 1 month of bevacizumab administration visual acuity (distant vision, near vision, and pinhole vision) was improved to logarithm of the minimum angle of resolution (MAR) 0.63 ± 0.07 from 0.87 ± 0.12 of distant vision. Pinhole vision was improved to log MAR 0.37 ± 0.06 from 0.478 ± 0.07 and near vision was improve to log MAR 0.477 ± 0.071 from 0.528 ± 0.069, and retinal thickness was decreased to 336 ± 17.35 μm from 429 ± 30.20 μm. Mean macular thickness was improved to 363.75 ± 24.54 μm from 452.37 ± 30.99 μm. Conclusion: Hence, the off-label use of bevacizumab for the said treatment may be proven beneficial.

Vitreous levels of placental growth factor correlate with activity of proliferative diabetic retinopathy and are not influenced by bevacizumab treatment.

PurposePlacental growth factor (PlGF) is a member of the VEGF family that plays an important role in experimental models of diabetic retinopathy and retinal neovascularization. We aimed to investigate whether vitreous levels of PlGF correlated with proliferative diabetic retinopathy (PDR) status, VEGF levels, and bevacizumab treatment. We also analysed PDR membranes to confirm the presence of the PlGF receptor, FLT1, in endothelial cells.MethodsThis was a case-control study: undiluted vitreous fluid samples were obtained from 28 active PDR patients without preoperative bevacizumab treatment, 21 active PDR patients with preoperative bevacizumab treatment, 18 inactive PDR patients, and 21 control patients. PlGF and VEGF levels in samples were determined by enzyme-linked immunosorbent assay. Immunohistochemistry for FLT1 was performed on human PDR membranes.ResultsCompared to control, vitreous PlGF levels were higher in both active PDR without bevacizumab (P<0.0001) and with bevacizumab (P<0.0001). There was no significant difference in PlGF between active PDR patients without and with bevacizumab (P=0.56). Compared to active PDR, PlGF levels were significantly reduced in inactive PDR (P=0.004). PlGF levels were highly correlated with VEGF levels in active PDR. VEGFR1 was expressed in endothelial cells in human PDR membranes.ConclusionThe strong correlation of PlGF levels with PDR disease status and expression of FLT1 in human PDR membranes suggest that PlGF has a pathogenic role in proliferative diabetic retinopathy. Therapeutic targeting of PlGF with agents like aflibercept may be beneficial.

Progression of Diabetic Capillary Occlusion: A Model.

An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions.

Influence of diabetes and diabetes type on anatomic and visual outcomes following central rein vein occlusion

To determine the influence of diabetes and diabetes type on ocular outcomes following central retinal vein occlusion (CRVO). Retrospective chart review of all patients evaluated over a 4-year period in a tertiary diabetes eye care center. Ophthalmic findings were recorded including visual acuity and the presence of retinal neovascularization at presentation, after 3-6 months, and at last follow-up. The records of 19,648 patients (13,571 diabetic; 6077 nondiabetic) were reviewed. The prevalence of CRVO in diabetic patients (N=72) and nondiabetic patients (N=27) were 0.5 and 0.4%, respectively. Disc neovascularization (21.3 vs 0.0%, P=0.05) and panretinal photocoagulation (PRP) (48.7 vs 21.4%, P=0.01) were more common in diabetic patients compared with nondiabetic patients. Compared with type 2 diabetic patients, retinal neovascularization (28.6 vs 3.7%, P=0.004) and subsequent PRP (78.6 vs 41.9%, P=0.01) were more likely in type 1 patients. Optic nerve head collateral vessels (CVs) were observed less than half as often (21.4 vs 56.5%, P=0.04) in patients with type 1 diabetes. Presence of optic nerve head CVs at baseline was associated with less likelihood of PRP (14.3 vs 46.1%, P=0.03). In this cohort, the rates of CRVO in diabetic and nondiabetic patients were similar to previously published population-based studies. Following CRVO, diabetic patients had higher rates of disc neovascularization and were more likely to require subsequent PRP than nondiabetic patients. As compared with CRVO patients with type 2 diabetes, patients with type 1 diabetes and CRVO had worse anatomic outcomes with substantially increased risks of retinal neovascularization and PRP; however, final visual acuity outcomes were similar.

Fourier-domain optical coherence tomography evaluation of retinal and optic nerve head neovascularisation in proliferative diabetic retinopathy

AimTo describe the in vivo spatial and morphological vitreoretinal relationships associated with diabetic retinal neovascularisation using Fourier-domain optical coherence tomography (FD-OCT).MethodsQualitative assessment of macula, retina and optic disc head FD-OCT...

Attenuation of streptozotocin-induced diabetic retinopathy with low molecular weight fucoidan via inhibition of vascular endothelial growth factor

Diabetic retinopathy (DR) is a hyperglycemia-induced ischemic disorder characterized by microvascular dysfunction and neovascularization. It is a leading cause of blindness in many countries, yet efficient drugs are limited now for prevention and treatment of DR. Low molecular weight fucoidan (LMWF), extract from brown algae, has been shown to possess multiple biological activities like anti-inflammation, anti-oxidation and anti-aggregation, which all could be beneficial for attenuating ischemia-induced tissue damages. Here, by comparing with calcium dobesilate, the potent antioxidant compound currently used for the treatment of DR, we investigated the protective effect of LMWF against DR in streptozotocin-induced diabetic mice and high glucose-promoted vascular endothelial growth factor (VEGF) production and cell proliferation in microvascular endothelial cells. One week after diabetes induction, the mice were administered with LMWF (50, 100 or 200 mg/kg/day) or calcium dobesilate (200 mg/kg/day) for four months, then the retinal pathological changes and neovascularization were detected by hematoxylin-eosin staining and fluorescein dextran angiography, respectively. Immunofluorescence staining, ELISA and RT-PCR were used to examine the expression levels of hypoxia-inducible factor-1α (HIF-1α) and VEGF in retina and endothelial cells. Here, we found that LMWF resembled calcium dobesilate, in alleviating retinal pathological change and hindering neovascularization due to diabetes in vivo. The relative levels of VEGF expression and HIF-1α induction were also less in retinas of LMWF- or calcium dobesilate-treated diabetic mice than those in retinas of control mice. Furthermore, high glucose-induced VEGF overexpression and cell proliferation in primary cultured vascular endothelial cells were also inhibited by LMWF in a dose-dependent manner. Therefore, this study demonstrated that LMWF alleviates diabetic retinal neovascularization and damage likely through lowering HIF-1α and VEGF expressions, providing a potential candidate drug for prevention and treatment of diabetic retinopathy.

Decursin inhibited proliferation and angiogenesis of endothelial cells to suppress diabetic retinopathy via VEGFR2

Diabetes induces pathologic proliferation and angiogenesis in the retina that leads to catastrophic loss of vision. Decursin is a novel therapeutic that targets the vascular endothelial growth factor (VEGF) receptor (VEGFR) with putative anti-proliferative and anti-angiogenic activities. Thereby we utilized human retinal microvascular endothelial cells (HRMEC) and human umbilical vein endothelial cells (HUVEC) under conditions of excess glucose to explore dose-dependent responses of decursin on markers of migration, angiogenesis, and proliferation. Decursin dose-dependently inhibited tube formation, VEGFR-2 expression, along with relative metabolic activity and 5-bromo-2′-deoxy-uridine (BrdU) activity in both cell lines. We then correlated our findings to the streptozotocin-induced rat model of diabetes. Following three months of decursin treatment VEGFR-2 expression was significantly inhibited. Our data would suggest that decursin may be a potent anti-angiogenic and anti-proliferative agent targeting the VEGFR-2 signaling pathway, which significantly inhibits diabetic retinal neovascularization.

INTRAVITREAL BEVACIZUMAB IN THE TREATMENT OF DIABETIC OCULAR NEOVASCULARIZATION

To evaluate the efficacy of intravitreal bevacizumab for treating diabetic retinal and/or iris neovascularization. Consecutive, prospective, interventional case series study of 60 eyes with diabetic retinal and/or iris neovascularization. Patients had a complete ocular examination before receiving 1.25 mg (0.05 mL) of intravitreal bevacizumab. Abnormal new vessels elsewhere in the retina, optic disk, or iris were graded by size and associated hemorrhage or glaucoma. Patients had complete postinjection ophthalmic evaluations with regrading of the abnormal new vessels at 3 months and 6 months. The main outcome measures included clinical partial or total regression of abnormal new vessels, changes in visual acuity, and complications related to the intravitreal injections. Twenty-six patients (47.3%) were men (mean age, 59 years). Abnormal new vessel regression at 6 months occurred in 65% of new vessels of the iris (P = 0.001), 45% of new vessels of the optic disk (P = 0.009), and 43% of new vessels elsewhere (P = 0.008). The visual acuity improved in 20% of eyes, which was not significant (P = 0.235); the visual acuity deteriorated in 23% of eyes (P = 0.163). No systemic or ocular side effects developed except for postinjection hypotony in one eye. Intravitreal bevacizumab is a well-tolerated medication that causes regression of abnormal diabetic neovascularization. New vessels of the iris responded more than new vessels of the optic disk and new vessels elsewhere.

RETINAL NEOVASCULARIZATION SECONDARY TO PROLIFERATIVE DIABETIC RETINOPATHY CHARACTERIZED BY SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

The purpose of this study was to characterize diabetic retinal neovascularization (NV) and accompanying retinal and vitreal morphologic changes using high-resolution spectral domain optical coherence tomography. A cross-sectional retrospective analysis was performed on 16 eyes of 14 nonconsecutive subjects with proliferative diabetic retinopathy that were seen between August 2011 and December 2011 at the New England Eye Center, Boston, MA. Patients who had NV of the disk, NV elsewhere, and intraretinal microvascular abnormalities were scanned using optical coherence tomography directly over the region of the abnormal vessels. Characteristic changes of the retinal vasculature, retina, and vitreous were seen in the 16 eyes with NV. This study describes optical coherence tomography characteristics of 1) NV of the disk, 2) NV elsewhere, 3) intraretinal microvascular abnormality, 4) NV causing traction without retinal detachment; and 5) NV causing traction with retinal detachment. The morphologic appearance of vitreous traction was found to be consistent with the previous histologic reports. It is possible to image diabetic NV using spectral domain optical coherence tomography and to visualize the spectrum of retinal, retinal vascular, and vitreal changes seen through these areas of abnormal retinal vasculature.