Central Retinal Vein Occlusion: A Review of Current Evidence-based Treatment Options

Risk Factors for Developing Neovascular Glaucoma in Central Retinal Vein Occlusion: Two-Year Real-World Study

PURPOSE

To explore potential risk factors for the development of neovascular glaucoma (NVG) in central retinal vein occlusion (CRVO) over a two-year intensive follow-up period.

METHODS

This study reviewed 1545 patients with CRVO between 2005 and 2019 at Taipei Veterans General Hospital. Inclusion was restricted to (1) patients with acute CRVO within 3 months; (2) patients with ocular neovascularization at initial presentation (3) patients had not received any treatment at the time of CRVO; (4) at least bimonthly follow-up schedule over the course of 2 years. The included patients were screened for potential risk factors for developing NVG and assessed with Kaplan-Meier survival analysis and Cox regression model.

RESULTS

Among the included 123 patients, the cumulative probability of developing NVG was 26.8% (33/123 cases) in overall follow-up period. The mean interval between the onset of CRVO and NVG was 507 days. Neither macular edema nor central macular thickness at baseline was correlated with the development of NVG (p =.104 and .25, respectively). Patients with diabetes mellitus (DM), older age, and poor vision independently played significant risk factors for developing NVG after controlling other covariates. (p =.034, .001, and .013, respectively).

CONCLUSIONS

Patients presenting with CRVO who have comorbidities such as DM, older age, and worse VA warrant closer attention and intensive follow-up for the development of NVG. Additionally, the statistical analysis indicated that the presence of macular edema, increased central macular thickness, CV events, history of glaucoma, and early PRP within 3 months had no significant impact on the likelihood of developing NVG.

The application of functional imaging in visual field defects: a brief review

Visual field defects (VFDs) represent a prevalent complication stemming from neurological and ophthalmic conditions. A range of factors, including tumors, brain surgery, glaucoma, and other disorders, can induce varying degrees of VFDs, significantly impacting patients' quality of life. Over recent decades, functional imaging has emerged as a pivotal field, employing imaging technology to illustrate functional changes within tissues and organs. As functional imaging continues to advance, its integration into various clinical aspects of VFDs has substantially enhanced the diagnostic, therapeutic, and management capabilities of healthcare professionals. Notably, prominent imaging techniques such as DTI, OCT, and MRI have garnered widespread adoption, yet they possess unique applications and considerations. This comprehensive review aims to meticulously examine the application and evolution of functional imaging in the context of VFDs. Our objective is to furnish neurologists and ophthalmologists with a systematic and comprehensive comprehension of this critical subject matter.

Sleep-disordered breathing is related to retinal vein occlusion: A meta-analysis

BACKGROUND

Previous studies suggest that sleep-disordered breathing (SDB) may be a potential risk factor of retinal vein occlusion (RVO). We conducted a meta-analysis to systematically explore the relationship between RVO and SDB.

METHODS

Observational studies assessing the relationship between SDB and RVO were retrieved by searches of electronic databases including the PubMed, Embase, Web of Science, China National Knowledge Infrastructure, and Wan Fang databases from database inception to August 9, 2023. In consideration of intra-study heterogeneity, a random-effects model was adopted to combine the results.

RESULTS

Seven studies (1 retrospective cohort and 6 case-control studies) were included in this meta-analysis, and among 36,628 adults included in those studies, 6452 (17.6%) had SDB. The combined results indicated that SDB was associated with RVO [risk ratio (RR): 1.92, 95% confidence interval (CI): 1.60-2.30, P < .001] with no significant heterogeneity (I2 = 0%). Subgroup analyses showed consistent relationships between SDB and any RVO (RR: 1.73, 95% CI: 1.13-2.28, P < .001), central RVO (RR: 2.20, 95% CI: 1.57-3.08, P < .001), and branch RVO (RR: 1.85, 95% CI: 1.15-2.99, P = .01). Moreover, the relationship was consistent among patients with mild (RR: 1.82, 95% CI: 1.32-2.53, P < .001), moderate (RR: 2.17, 95% CI: 1.65-2.85, P < .001), and severe SDB (RR: 2.66, 95% CI: 1.96-3.62, P < .001). The association was consistent in studies that adjusted for age and sex (RR: 2.17, 95% CI: 1.50-3.13, P < .001), and in studies with additional adjustment for comorbidities (RR: 1.78, 95% CI: 1.42-2.25, P < .001).

CONCLUSION

SDB is associated with RVO in adults.

[Analysis of adverse drug reactions (ADR) in fluorescein angiography (FAG) and indocyanine green angiography (ICGA) and indications before and during the COVID-19 pandemic at a university eye hospital]

BACKGROUND

This study was an analysis of fluorescein angiography (FAG) and indocyanine green angiography (ICGA) at a university eye hospital. The primary objective of the study was to analyze adverse drug reactions (ADRs) and their severity (mild, moderate, severe). The secondary objective was to investigate the indications of FAG and ICGA before and during the COVID-19 pandemic.

METHODS

A retrospective analysis of all FAG and ICGA at the University Eye Hospital in Würzburg from January 2016 to the end of December 2021 was performed. The ADRs, gender, age, examination time points and indications were evaluated. The ADRs were classified into mild, moderate, and severe, following the definition of Kornblau et al. [1] RESULTS: A total of 4900 examinations from 4193 patients were analyzed. An FAG was performed slightly more frequently in men (54.8%) than in women (45.2%) and the mean age was 63.2 ± 16.9 years (median: 65 years). The ADRs occurred in only 1.65% of all FAG, of which 1.27% were mild and 0.39% were moderate. No severe ADRs occurred. The most common ADR was nausea at 59.26%. No ADR occurred in ICGA. The annual number of FAGs averaged 816.7 ± 91.1 and was relatively constant throughout the period except for a significantly reduced number in 2016 (compared with 2018, 2019, and 2021). The most common indication for FAG was venous retinal occlusion at 22.93% (N = 774), showing a significant increase in 2021 compared to 2018-2020. An ICGA was performed in 4.18% of cases, with the most common indication being uveitis at 31.82% (N = 63).

CONCLUSION

Compared to other studies very few ADRs occurred and no life-threatening ADR occurred in any case. Venous retinal occlusions were very common indications for FAG, probably due to the frequent need for repeated examinations in this condition. Briefly, during the first lockdown (18 March-8 May 2020), a decrease in angiographies was observed, but over a longer period, no significant differences were seen compared with the prepandemic period.

Establishment of a minimally invasive distal traumatic optic neuropathy model in mice to investigate cascade reactions of retinal glial cells

Traumatic optic neuropathy (TON) is a complication of craniocerebral, orbital and facial injuries, leading to irreversible vision loss. At present, there is no reliable, widely used animal model, although it has been confirmed that TON can cause the loss of retinal ganglion cells (RGC). However, the cascade reaction of retinal glial cells underlying TON is unclear. Therefore, the establishment of an animal model to explore the pathological mechanism of TON would be of great interest to the scientific community. In this study, we propose a novel mouse model utilizing a 3D stereotaxic apparatus combined with a 27G needle to evaluate damage to the optic nerve by micro-CT, anatomy, SD-OCT and F-VEP. Immunofluorescence, western blotting, qPCR experiments were conducted to investigate the loss of RGCs and activation or inactivation of microglia, astrocytes and Müller glial cells in the retina from the first week to the fourth week after modeling. The results showed that this minimally invasive method caused damage to the distal optic nerve and loss of RGC after optic nerve injury. Microglia cells were found to be activated from the first week to the third week; however, they were inactivated at the fourth week; astrocytes were activated at the second week of injury, while Müller glial cells were gradually inactivated following injury. In conclusion, this method can be used as a novel animal model of distal TON, that results in a series of cascade reactions of retinal glial cells, which will provide a basis for future studies aimed at exploring the mechanism of TON and the search for effective treatment methods.

Development and Application of an Intelligent Diagnosis System for Retinal Vein Occlusion Based on Deep Learning

This study is aimed at developing an intelligent algorithm based on deep learning and discussing its application for the classification and diagnosis of retinal vein occlusions (RVO) using fundus images. A total of 501 fundus images of healthy eyes and patients with RVO were used for model training and testing to investigate an intelligent diagnosis system. The images were first classified into four categories by fundus disease specialists: (i) healthy fundus (group 0), (ii) branch RVO (BRVO) (group 1), (iii) central RVO (CRVO) (group 2), and (iv) macular branch RVO (MBRVO) (group 3), before being diagnosed using the ResNet18 network model. Intelligent diagnoses were compared with clinical diagnoses. The specificity of the intelligent diagnosis system under each attention mechanism was 100% in group 0 and also revealed a high sensitivity of over 95%, F1 score of over 97%, and an accuracy of over 97% in this group. For the other three groups, the specificities of diagnosis ranged from 0.45 to 0.91 with different attention mechanisms, in which the ResNet18+coordinate attention (CA) model had the highest specificities of 0.91, 0.88, and 0.83 for groups 1, 2, and 3, respectively. It also provided a high accuracy of over 94% with a coordinate attention mechanism in all four groups. The intelligent diagnosis and classifier system developed herein based on deep learning can determine the presence of RVO and classify disease according to the site of occlusion. This proposed system is expected to provide a new tool for RVO diagnosis and screening and will help solve the current challenges due to the shortage of medical resources.

Bilateral Central Retinal Vein Occlusion as a First Presentation of Multiple Myeloma: A Case Report

Introduction: Acute presentation of multiple myeloma in the emergency department (ED) is an uncommon yet life-threatening clinical entity. Case Report: A 42-year-old male presented to the ED with severe generalized fatigue and vision changes most notable in his left eye. Bilateral central retinal vein occlusion (CRVO) was diagnosed on dilated fundus exam in the ED. Conclusion: The most common cause of CRVO in adults over age 50 is vascular disease, but in younger adults, conditions of systemic inflammation or hyperviscosity must be considered. Diagnosis of CRVO requires emergent ophthalmology consultation and further treatment with phototherapy, steroids, and potentially anti-vascular endothelial growth factor. Ultimately, patients require hematology/oncology and ongoing management of acute hyperviscosity syndrome. We present this case to increase awareness surrounding this diagnosis among emergency physicians. Multiple myeloma should be considered in young patients who present to the ED with bilateral CRVO, acute renal failure, and symptomatic anemia.

Choroidal Vascularity Index in Central and Branch Retinal Vein Occlusion

(1) Background: we aimed to evaluate choroidal vascularity change in eyes with central and branch retinal vein occlusion (RVO). (2) Methods: in this retrospective cross-sectional study, we reviewed the records of 47 patients with recent-onset, naïve, unilateral retinal vein occlusion. Enhanced-depth imaging optical coherence tomography scans were binarized using the ImageJ software; luminal area (LA) and total choroidal area (TCA) were measured. The choroidal vascularity index (CVI) was calculated as the proportion of LA to TCA. Depending on the pattern of macular oedema, eyes were classified as having no macular oedema (nME), cystoid macular oedema (CME), cystoid macular oedema with serous retinal detachment (mixed). (3) Results: CVI, TCA and LA were greater in eyes with RVO than in fellow, unaffected eyes. No difference was found between central and branch RVO except for central macular thickness (CMT). When compared with controls, eyes with CME presented a significant increase in subfoveal choroidal thickness, CMT, TCA, LA and CVI; eyes with mixed macular oedema had greater CMT and CVI than contralateral eyes; no significant differences in any of the considered parameters were observed in eyes with nME. (4) Conclusions: The results suggest that RVO alters the vascularity of the choroid that varies according to the type of macular oedema.

Bilateral Central Retinal Vein Occlusion as a First Presentation of Multiple Myeloma: A Case Report

INTRODUCTION

Acute presentation of multiple myeloma in the emergency department (ED) is an uncommon yet life-threatening clinical entity.

CASE REPORT

A 42-year-old male presented to the ED with severe generalized fatigue and vision changes most notable in his left eye. Bilateral central retinal vein occlusion (CRVO) was diagnosed on dilated fundus exam in the ED.

CONCLUSION

The most common cause of CRVO in adults over age 50 is vascular disease, but in younger adults, conditions of systemic inflammation or hyperviscosity must be considered. Diagnosis of CRVO requires emergent ophthalmology consultation and further treatment with phototherapy, steroids, and potentially anti-vascular endothelial growth factor. Ultimately, patients require hematology/oncology and ongoing management of acute hyperviscosity syndrome. We present this case to increase awareness surrounding this diagnosis among emergency physicians. Multiple myeloma should be considered in young patients who present to the ED with bilateral CRVO, acute renal failure, and symptomatic anemia.

Idiopathic combined retinal vessels occlusion in a pregnant woman: a case report

Background

Ocular vascular occlusion is an extremely rare event, especially in the young population. This diagnosis is always associated with active systemic diseases in young adults and needs thrombophilia workup. Nevertheless, we present the case of a pregnant woman suffering from idiopathic combined central retinal vein and cilioretinal artery occlusion.

Case presentation

A 36-year-old pregnant Iranian woman at the 36th week of her second pregnancy complained of subacute unilateral painless decreased vision of her left eye. She had experienced a transient vision loss that lasted several minutes, but attacks gradually became more frequent and finally persistent over a several-day period. Finally combined central retinal vein and cilioretinal artery occlusion was established. Her visual acuity improved to 4/10 in a month without any ocular intervention except for a short duration of prophylactic dose enoxaparin, and the acuity reached 8/10 without any complications in the third month follow-up visit. At 1 year follow-up, the visual acuity had not changed and no macular edema was seen.

Conclusions

Ocular vascular occlusion is extremely rare among young adults, and even rarer among pregnant women. According to this, any suspected retinal vascular event in this population should raise suspicion for underlying diseases such as hypertension, diabetes, autoimmune diseases, migraine, preeclampsia syndrome, and thrombophilia. However, as seen in this presented case, idiopathic ocular vascular occlusion events can occur also.

Retinal Vein Occlusion with COVID-19: A Case Report and Review of Literature

OBJECTIVES

To provide a case report of Retinal Vein Occlusion (RVO) with COVID-19 infection.

CASE

A 15-year-old healthy male presented with blurring of vision, 2+ vitreous cells, retinal haemorrhages and dilated and tortuous retinal vessels in the left eye within 28 days of a positive COVID-19 reverse transcriptase polymerase chain reaction (RT-PCR) assay. He was diagnosed with left non-ischaemic CRVO, with a suspected aetiology of COVID-19.

DISCUSSION

A literature review found 12 reported cases of RVO associated with COVID-19. All but one patient was younger than 60, with a mean age of 42 years. Management varied, but in the majority (8/12), visual acuity (VA) improved with follow-up, and five (42%) had a final VA of 20/20.

CONCLUSION

In the absence of other known aetiological factors, ophthalmologists should consider COVID-19 as a cause of RVO. The outcome can vary, but the majority can expect improvement in VA with time.

Characteristics and risk factors of retinal vasculopathy in antiphospholipid syndrome

BACKGROUND

Retinal vasculopathy including retinal artery occlusion (RAO) or retinal vein occlusion (RVO) was recently found to occur more frequently in antiphospholipid syndrome (APS) patients than non-APS patients. This study aims to investigate the clinical manifestation and risk factors of retinal vasculopathy among APS patients.

METHODS

In this single-center prospective cohort study, we evaluated APS patients with or without retinal vasculopathy during 2018-2020 at Peking Union Medical College Hospital. Clinical variables were compared, and a logistical regression model was built to explore risk factors. Hierarchical cluster analysis using Euclidean distances was applied to identify clusters of variables.

RESULTS

A total of 310 APS patients (67.4% female, mean age 38.1 years) were included, of whom 18 (5.8%) were diagnosed with retinal vasculopathy (9 with RVO and 9 with RAO). No significant differences were found among most demographic characteristics, clinical manifestations, or antibody profiles. APS-related heart valve disease (odds ratio OR 13.66, 95% confidence interval CI 4.55-40.98), APS nephropathy (OR 12.77, 95% CI 4.04-40.35), and thrombocytopenia (OR 2.63, 95% CI 1.01-6.89) were predictive of retinal vasculopathy. APS-related heart valve disease and nephropathy were also found to be statistically significant predictors in multivariate logistical regression analysis. Non-criteria manifestations were aggregated with retinal vasculopathy from a cluster analysis of variables.

CONCLUSION

Patients with APS-related heart valve disease and nephropathy suffered a higher risk of retinal vasculopathy. The underlying mechanisms of aPL-associated retinal vasculopathy may involve thrombotic microangiopathy, leading to poor prognosis and therapeutic changes.

Intravitreal ranibizumab versus aflibercept versus bevacizumab for macular oedema due to central retinal vein occlusion: the LEAVO non-inferiority three-arm RCT

BACKGROUND

Licensed ranibizumab (0.5 mg/0.05 ml Lucentis®; Novartis International AG, Basel, Switzerland) and aflibercept (2 mg/0.05 ml Eylea®; Bayer AG, Leverkusen, Germany) and unlicensed bevacizumab (1.25 mg/0.05 ml Avastin®; F. Hoffmann-La Roche AG, Basel, Switzerland) are used to treat macula oedema due to central retinal vein occlusion, but their relative clinical effectiveness, cost-effectiveness and impact on the UK NHS and Personal Social Services have never been directly compared over the typical disease treatment period.

OBJECTIVE

The objective was to compare the clinical effectiveness and cost-effectiveness of three intravitreal antivascular endothelial growth factor agents for the management of macula oedema due to central retinal vein occlusion.

DESIGN

This was a three-arm, double-masked, randomised controlled non-inferiority trial.

SETTING

The trial was set in 44 UK NHS ophthalmology departments, between 2014 and 2018.

PARTICIPANTS

A total of 463 patients with visual impairment due to macula oedema secondary to central retinal vein occlusion were included in the trial.

INTERVENTIONS

The participants were treated with repeated intravitreal injections of ranibizumab (n = 155), aflibercept (n = 154) or bevacizumab (n = 154).

MAIN OUTCOME MEASURES

The primary outcome was an increase in the best corrected visual acuity letter score from baseline to 100 weeks in the trial eye. The null hypothesis that aflibercept and bevacizumab are each inferior to ranibizumab was tested with a non-inferiority margin of -5 visual acuity letters over 100 weeks. Secondary outcomes included additional visual acuity, and imaging outcomes, Visual Function Questionnaire-25, EuroQol-5 Dimensions with and without a vision bolt-on, and drug side effects. Cost-effectiveness was estimated using treatment costs and Visual Function Questionnaire-Utility Index to measure quality-adjusted life-years.

RESULTS

The adjusted mean changes at 100 weeks in the best corrected visual acuity letter scores were as follows - ranibizumab, 12.5 letters (standard deviation 21.1 letters); aflibercept, 15.1 letters (standard deviation 18.7 letters); and bevacizumab, 9.8 letters (standard deviation 21.4 letters). Aflibercept was non-inferior to ranibizumab in the intention-to-treat population (adjusted mean best corrected visual acuity difference 2.23 letters, 95% confidence interval -2.17 to 6.63 letters; p = 0.0006), but not superior. The study was unable to demonstrate that bevacizumab was non-inferior to ranibizumab in the intention-to-treat population (adjusted mean best corrected visual acuity difference -1.73 letters, 95% confidence interval -6.12 to 2.67 letters; p = 0.071). A post hoc analysis was unable to demonstrate that bevacizumab was non-inferior to aflibercept in the intention-to-treat population (adjusted mean best corrected visual acuity difference was -3.96 letters, 95% confidence interval -8.34 to 0.42 letters; p = 0.32). All per-protocol population results were the same. Fewer injections were required with aflibercept (10.0) than with ranibizumab (11.8) (difference in means -1.8, 95% confidence interval -2.9 to -0.8). A post hoc analysis showed that more bevacizumab than aflibercept injections were required (difference in means 1.6, 95% confidence interval 0.5 to 2.7). There were no new safety concerns. The model- and trial-based cost-effectiveness analyses estimated that bevacizumab was the most cost-effective treatment at a threshold of £20,000-30,000 per quality-adjusted life-year.

LIMITATIONS

The comparison of aflibercept and bevacizumab was a post hoc analysis.

CONCLUSION

The study showed aflibercept to be non-inferior to ranibizumab. However, the possibility that bevacizumab is worse than ranibizumab and aflibercept by 5 visual acuity letters cannot be ruled out. Bevacizumab is an economically attractive treatment alternative and would lead to substantial cost savings to the NHS and other health-care systems. However, uncertainty about its relative effectiveness should be discussed comprehensively with patients, their representatives and funders before treatment is considered.

FUTURE WORK

To obtain extensive patient feedback and discuss with all stakeholders future bevacizumab NHS use.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN13623634.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 38. See the NIHR Journals Library website for further project information.

Immunosubunit β5i Knockout Suppresses Neovascularization and Restores Autophagy in Retinal Neovascularization by Targeting ATG5 for Degradation

Purpose

To investigate the functional role of immunoproteasome subunit β5i in pathologic retinal neovascularization (RNV) and its ability to link the immunoproteasome and autophagy.

Methods

Oxygen-induced retinopathy (OIR) was induced in wild-type (WT) and β5i knockout (KO) mouse pups on a C57BL/6J background. Proteasome catalytic subunit expression and proteasome activity were evaluated by quantitative real-time PCR (qPCR) and proteasome activity. Retinal vascular anatomy and neovascularization were characterized and quantified by retinal vascular flat-mount staining, fluorescence angiography, platelet endothelial cell adhesion molecule (PECAM) immunostaining, and hematoxylin and eosin staining. Correlation factors, including VEGF and ICAM-1, were detected by qPCR. Autophagy was examined by transmission electron microscopy (TEM). Autophagy biomarkers, including LC3, P62, ATG5, and ATG7, were measured by immunostaining and immunoblotting. The protein interaction between β5i and ATG5 was detected by immunoprecipitation.

Results

We observed that β5i had the greatest effect in WT OIR mice. Fundus fluorescence angiography, retinal flat-mount staining, and PECAM staining revealed that pathologic RNV decreased in β5i KO OIR mice compared with WT OIR mice. Concurrently, TEM, immunostaining, and immunoblotting showed that autophagy was induced in β5i KO OIR mice compared to WT OIR mice through increases in autophagosome and LC3 expression and a decrease in P62. Mechanistically, β5i interacted with ATG5 and promoted its degradation, leading to autophagy inhibition and pathogenic RNV.

Conclusions

This study identifies a functional role for β5i in RNV regulation. β5i deletion ameliorates RNV and restores autophagy by stabilizing ATG5. These results demonstrate the potential of β5i to serve as a bridge linking the immunoproteasome and autophagy.

Rebound Phenomenon after Intravitreal Injection of Triamcinolone Acetonide for Macular Edema

INTRODUCTION

The aim of this article was to report on a rebound phenomenon after intravitreal triamcinolone acetonide (IVTA) injection for macular edema secondary to diabetic retinopathy (DR) and central or branch retinal vein occlusion (CRVO/BRVO).

METHODS

The data were analyzed retrospectively. Complete ophthalmic examinations, including spectral domain optical coherence tomography, were performed before and 2 months after IVTA injection. The incidence of a rebound phenomenon was defined as an increase in central retinal thickness of >10% from baseline at 2 months after IVTA injection.

RESULTS

This retrospective study included 211 consecutive patients (268 eyes). One hundred ninety (71.2%), 39 (14.6%), and 39 (14.6%) eyes had macular edema (ME) due to DR, CRVO, and BRVO. In total, 9.7% of the eyes showed a rebound phenomenon (DR: 9.5%, CRVO: 5.2%, BRVO: 15.4%). The mean number of prior injections of vascular endothelial growth factor inhibitor or corticosteroid agent was statistically significantly higher in the rebound group (6.8 vs. 5.3) than in the nonrebound group (p = 0.01).

CONCLUSION

Our study shows that 9.7% of the eyes with ME secondary to DR and RVO developed a rebound phenomenon following IVTA injection, limiting its therapeutic effect. We found an increased number of prior intravitreal pharmacotherapy to be a risk factor for a rebound phenomenon.

Clinical efficacy evaluation of treatment of different degrees of retinal vein occlusion with ranibizumab combined with an argon ion laser

The aim of this study was to evaluate the clinical efficacy of an intravitreal injection of ranibizumab combined with argon ion laser photocoagulation therapy in the treatment of different degrees of central retinal vein occlusion (CRVO). A total of 112 CRVO patients including 25 cases of trunk occlusion, 50 cases of branch occlusion and 37 cases of hemiretinal vein-occlusion were enrolled in this study. Patients were treated with an intravitreal injection of 0.5 mg ranibizumab, followed by argon ion laser photocoagulation therapy after 7 days. Patients were followed up for 6 months and the best corrected visual acuity (BCVA), central retinal thickness (CRT), macular edema, and surgical complications were compared. Compared with the control treated with 0.5 mg ranibizumab, the BCVA and macular edema improved while CRT was significantly reduced in all groups treated with 0.5 mg ranibizumab combined with the argon ion laser. Furthermore, no obvious complications were observed in these groups and the effects of ranibizumab combined with argon ion laser photocoagulation on branch occlusion group were the best. Intravitreal injection of ranibizumab combined with argon ion laser photocoagulation therapy has better safety and effectiveness in the treatment of different degrees of CRVO. The trial registration number is 2015–318 and date of registration is 12/10/2015.

Optical coherence tomography angiography

Optical coherence tomography (OCT) was one of the biggest advances in ophthalmic imaging. Building on that platform, OCT angiography (OCTA) provides depth resolved images of blood flow in the retina and choroid with levels of detail far exceeding that obtained with older forms of imaging. This new modality is challenging because of the need for new equipment and processing techniques, current limitations of imaging capability, and rapid advancements in both imaging and in our understanding of the imaging and applicable pathophysiology of the retina and choroid. These factors lead to a steep learning curve, even for those with a working understanding dye-based ocular angiography. All for a method of imaging that is a little more than 10 years old. This review begins with a historical account of the development of OCTA, and the methods used in OCTA, including signal processing, image generation, and display techniques. This forms the basis to understand what OCTA images show as well as how image artifacts arise. The anatomy and imaging of specific vascular layers of the eye are reviewed. The integration of OCTA in multimodal imaging in the evaluation of retinal vascular occlusive diseases, diabetic retinopathy, uveitis, inherited diseases, age-related macular degeneration, and disorders of the optic nerve is presented. OCTA is an exciting, disruptive technology. Its use is rapidly expanding in clinical practice as well as for research into the pathophysiology of diseases of the posterior pole.