Manifestations of central retinal artery occlusion revealed by fundus fluorescein angiography are associated with the degree of visual loss

Therapeutic potential of integrins in diabetic retinopathy

Diabetic retinopathy (DR), a leading cause of visual loss, is the result of microvascular damage induced by prolonged hyperglycemia. Numerous studies have revealed the pivotal role of integrins in the pathogenesis of DR, particularly in key processes such as inflammation, vascular leakage, microthrombus formation, and angiogenesis. Consequently, targeting integrins is considered a promising strategy for the treatment of DR. This review focuses on the function of integrins in DR and their potential as therapeutic targets. It describes the molecular mechanisms through which integrins influence DR progression and summarizes the latest outcomes of integrin antagonist-based therapeutic strategies in clinical studies, evaluating their efficacy and potential challenges, which offer promise as novel treatment options for DR.

Multimodal Imaging Characteristics and Correlation to Outcomes in Patients With Central Retinal Artery Occlusion Presenting to a Large Academic Center

PURPOSE

To characterize a large modern cohort of patients with central retinal artery occlusion (CRAO) by describing presenting features and outcomes relating to manually segmented optical coherence tomography (OCT) features, angiographic reperfusion, and visual recovery.

DESIGN

Retrospective clinical cohort study.

METHODS

Patients with CRAO (ICD-10: H34.1) initially presenting to a tertiary referral center between January 2017 and December 2021 were included. Demographics, eye exam findings, fundus photographs, OCT, and fluorescein angiography were analyzed. Main outcome measures included total and inner retinal thickness on macular OCT, reperfusion, visual outcomes, and development of neovascularization.

RESULTS

A total of 145 eyes of 144 patients with mean age at of 69.4 ± 13.6 years were included. The mean time to presentation was 1.6 ± 4.2 days, with 19% examined within 4.5 hours and 26% within 6 hours of vision loss. 19% had cilioretinal artery (CLRA) sparing. Mean initial visual acuity (VA) was 1.68 ± 1.10 Logarithm of the Minimum Angle of Resolution (LogMAR) (CLRA sparing) compared to 2.53 ± 0.58 LogMAR (non-CLRA sparing), P < .001. 32% had elevated inflammatory makers. Out of 47 eyes with final fluorescein angiography, one-third showed some reperfusion. Final vision was 1.40 ± 1.16 LogMAR (CLRA sparing) compared to 2.46 ± 0.81 (non-CLRA sparing), P < .001. A third of patients improved in VA in both groups, 27% of patients gained more than 2 lines of vision in the CLRA-sparing group and 36% in the non-CLRA-sparing group. 17% improved to better than 20/200 in CLRA-sparing and 4% in non-CLRA sparing. Overall, 11% developed neovascularization all in non-CLRA sparing. In a multiple linear regression, VA at presentation was associated with regaining vision of 2 lines or more (OR = 2.603, P = .007). OCT showed progressive thinning over time, reaching lowest measurements at 6 months, and stabilizing thereafter.

CONCLUSIONS

In this modern cohort of acute CRAO patients, presentation to a tertiary facility within 12 hours of symptoms was seen in almost half of the patients. Final VA improved in almost a third of the patients, however, vision better than the legal blindness limit was rare (∼5%). Interestingly, a third of patients had some mild elevation of systemic inflammatory markers. Better VA at presentation was associated with visual gain, while baseline OCT values had poor correlation with final outcome.

Retinal Artery Occlusion: A Review of Current Management Practices

Retinal artery occlusion (RAO) is a well-characterized ischemic ophthalmic event that may result in sudden and devastating vision loss. The etiology of RAO may vary including both arteritic and non-arteritic causes and the location of the lesion can extend from the ophthalmic artery to the branches of the central retinal artery. Given this variable causes of RAO, the clinical presentation and extent of vision loss may also differ from case to case, necessitating a prompt and thorough evaluation, including a full stroke work up. While there is currently no widely accepted standard for the treatment of RAO, there are several proposed methods that have been or are currently being investigated through retrospective studies and prospective trials. The current article aims to provide a review of the pathophysiology, clinical presentation, and management of RAO in addition to presenting a systematic review of recently published studies on treatment options for RAO.

Abnormal retinal vessel filling in central retinal artery occlusion

CLINICAL RELEVANCE

Central retinal artery occlusion (CRAO) is an ophthalmic emergency with a poor prognosis. Several initial CRAO presentation factors can influence the final visual outcome. Fluorescein angiography filling of retinal vessels in CRAO has not been studied in great detail.

BACKGROUND

The aim of this paper is to study the aberrant filling of the retinal vessels on fluorescein angiography in patients with CRAO and understand its clinical relevance.

METHODS

Cases of CRAO diagnosed between June 2017 and May 2022 and who had undergone a fundus fluorescein angiography were included. Comparisons were made between the cases with and without aberrant filling of the retinal vessel.

RESULTS

Twenty-two eyes of 22 patients (14 males and 8 females) with CRAO underwent fluorescein angiography. Ages of the patients ranged from 18 to 73 years, while time interval between development of acute onset vision problems and presentation to the retinal clinic ranged from a minimum of 1 day to a maximum of 30 days. Snellen visual acuity at presentation ranged from perception of light (PL +) to 6/6. On fluorescein angiography, aberrant flow of the fluorescein dye into the retinal vein was observed in four of the 22 (18%) eyes with CRAO. All these cases showed a patient's temporal cilioretinal artery. The cases with aberrant filling of the retinal vessels showed a better presenting visual acuity (6/6-6/60), lesser severity of inner retinal damage and a better final visual acuity (6/6-6/60) compared to CRAO cases without aberrant filling.

CONCLUSION

Aberrant filling of the retinal vein can be seen on fluorescein angiography in eyes with CRAO and a patent temporal cilioretinal artery. Such eyes with aberrant retinal vessel filling have a better visual prognosis.

Central retinal artery occlusion: a stroke of the eye

Central retinal artery occlusion (CRAO), like a stroke in the brain, is a critical eye condition that requiring urgent medical attention. Patients with CRAO present with acute loss of vision and the visual prognosis is poor with low chance of spontaneous visual recovery. Moreover, the risk of developing ischaemic heart disease and cerebral stroke is increased due to the presence of underlying atherosclerotic risk factors. Currently, there is no officially recommended treatment for CRAO. This review will describe the anatomy, pathophysiology, clinical features of CRAO, as well as exploring existing and potential future approaches for managing the condition.

Update on central retinal artery occlusion

The medical condition referred to as "central retinal artery occlusion" (CRAO) was first documented by Albrecht von Graefe in 1859. Subsequently, CRAO has consistently been identified as a serious medical condition that leads to substantial visual impairment. Furthermore, it is correlated with vascular complications that have the potential to affect crucial organs such as the brain and heart. A considerable amount of research has been extensively published on the various aspects of this topic, which is marked by notable debates and misconceptions, especially regarding its management and outcomes. The primary aim of this review article is to analyze the latest developments in the understanding of CRAO, which includes its causes, techniques for retinal imaging, systemic evaluation, and therapeutic strategies, such as vitrectomy. This review article offers readers a comprehensive learning experience to gain knowledge on the fundamental principles and recent advancements in CRAO.

Clinical application of multicolor scanning laser ophthalmology in diagnosis and grading of central retinal artery occlusion

Purpose

To characterize features of central retinal artery occlusion (CRAO) using multicolor (MC) imaging and to assess the differences in CRAO grading between color fundus photography (CFP) and MC image qualitatively and quantitatively.

Methods

We conducted a prospective, cross-sectional study in the Department of Ophthalmology of Renmin Hospital of Wuhan University. In total, 86 acute CRAO patients were included. Spectral-domain optical coherence tomography (SD-OCT), CFP, and MC examinations were taken at baseline. Based on the findings of these three examinations, CRAO was divided into three grades (incomplete, subtotal, and total). Based on OCT grading criteria, we qualitatively compared the ability of grading CRAO by CFP and MC. CRAO patient's visual acuity (VA) was obtained from the initial visit. The retinal thickness was measured by SD-OCT. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) were obtained from optical coherence tomography angiography (OCTA) examinations. Quantitative data were compared across the three acute CRAO subgroups and against three examination findings.

Results

MC image had significantly higher power of acute CRAO detection than CFP (P = 0.03). In the same group of CRAO patients, there was no significant difference in VA when comparing OCT with the MC grading system or with the CFP grading system (all P > 0.05). Significant differences in VA were found between the three CRAO subgroups only under MC grading (P = 0.016). In incomplete CRAO patients, significant differences were found in central fovea thickness (CFT) when comparing OCT with the CFP grading system (P = 0.019). In the same group of CRAO patients, there was no significant difference in retinal thickness when comparing OCT with the MC grading system (All P > 0.05). Significance differences in CFT (P < 0.001), innermost retinal layer (IMRL; P < 0.01), middle retinal layer (MRL; P < 0.001), and outer retinal layer (ORL; P = 0.021) were found between the three CRAO subgroups by MC grading. Vessel density of SCP showed a statistically increased as the severity of three CRAO subgroups (P = 0.03), whereas DCP did not have significant differences (P = 0.745). Comparisons were made between the OCT grading method and the MC and CFP grading methods; there is no significant difference in vessel density of SCP and DCP (All P > 0.05).

Conclusion

The images obtained by MC are superior to those obtained by CFP in CRAO grading, retinal thickness, and vessel density measurement. MC imaging may be more capable of CRAO grading than OCT. We recommend MC imaging to determine CRAO severity to guide disease treatment and predict visual prognosis.

Retinal artery occlusion after ophthalmic surgery under regional anaesthesia: A narrative review

Two recent cases of central retinal artery occlusion under otherwise uncomplicated sub-Tenon's block that resulted in significant visual loss after cataract surgery prompted us to undertake a literature review of such cases. We identified 97 cases of retinal artery occlusion after ophthalmic surgery under regional anaesthesia that had no immediate signs of block-related complications. These occurred after various intraocular (87%) and extraocular (13%) operations, across a wide range of ages (19-89 years) on patients with (59%) or without (39%) known risk factors. The anaesthetic techniques included 40 retrobulbar blocks, 36 peribulbar blocks, 19 sub-Tenon's blocks, one topical anaesthetic and one unspecified local anaesthetic. Different strengths of lidocaine, bupivacaine, mepivacaine and ropivacaine, either alone or in various combinations, were used. The details of the anaesthetic techniques were often incomplete in the reports, which made comparison and analysis difficult. Only nine cases had their cause (optic nerve sheath injury) identified, while the mechanism of injury was unclear in the remaining patients. Various mechanisms were postulated; however, the cause was likely to be multifactorial due to patient, surgical and anaesthetic risk factors, especially in those with compromised retinal circulation. As there were no definite risk factors identified, no specific recommendations could be made to avoid this devastating outcome. We have provided rationales for some general considerations, which may reduce this risk, and propose anaesthetic options for ophthalmic surgery on the fellow eye if required, based both on our literature review and our personal experience.

OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity

AIM

To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion (NA-CRAO) via optical coherence tomography angiography (OCTA) and analyze their correlation with visual acuity.

METHODS

Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into: A type (mild n=29), B type (moderate n=27) and C type (severe n=6) based on the degree of visual loss, retinal edema, and arterial blood flow delay in fundus fluorescence angiography (FFA). Contralateral healthy eyes were used as the control group. Best-corrected visual acuity (BCVA), slit lamp microscopy, indirect ophthalmoscopy, fundus color photography, OCTA, and FFA were performed. Spearman's correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual acuity.

RESULTS

There were no statistically significant differences in age, gender, and intraocular pressure among the three types and the control group (P>0.05). Vessel density in deep capillary plexus (VD-DCP) significantly decreased (P<0.05) in all three types of NA-CRAO patients compared to the control group. Vessel density in superficial vascular plexus (VD-SVP) significantly decreased (P<0.05) in type A patients and choriocapillaris flow area significantly decreased (P<0.05) in type B and type C patients compared to the control group; while outer retinal flow areas significantly increased in the type A (P<0.05) and decreased in type C patients (P<0.05). The retinal thickness significantly increased in type C group (P<0.05). The VD-SVP at fovea in the type A was significantly lower than both of type B and C. The VD-SVP at nasal parafovea in type A and B was significantly lower than type C (P<0.05). The logMAR BCVA of type A was significantly better than that of type B and C groups (P<0.05). Spearman's correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea (r=0.679, P=0.031) and nasal parafovea (r=0.826, P=0.013).

CONCLUSION

OCTA is valuable for assessing retinal ischemia, and evaluating visual impairment. Deep retinal vasculature is commonly affected in all NA-CRAO types. VD-SVPs at fovea and nasal parafovea can serve as reliable markers of visual impairment in NA-CRAO.

Aberrant filling of the retinal vein on fluorescein angiography in branch and hemi-central retinal artery occlusion

OBJECTIVE

To study aberrant filling of the retinal vessels on fluorescein angiography (FA) images in patients with branch (BRAO) or hemi-central retinal artery occlusions (hemi-CRAO) and correlate with associated changes on optical coherence tomography (OCT).

METHODS

Cases of acute BRAO or hemi-CRAO having FA and OCT images at presentation between June 2017 to May 2022 were included. Comparisons were made between the cases with and without aberrant filling of the retinal vessel.

RESULTS

Thirty-nine eyes of 39 patients with acute retinal artery occlusions underwent FA and OCT imaging. Seven of the ten cases with either BRAO or hemi-CRAO showed aberrant filling of the retinal vein on FA. No case with CRAO showed aberrant filling on FA. The cases with aberrant filling showed a better presenting visual acuity and lesser severity of retinal ischemia on OCT. Shunts between the retinal artery in the unaffected region and the retinal vein in the affected segment was seen in two eyes. The remaining five eyes showed no arteriovenous anastomosis. Cases with aberrant filling had a better visual function even at the last visit.

CONCLUSION

Aberrant retinal vein filling across the horizontal median raphe in the affected region in BRAO or hemi-CRAO eyes had less severity of retinal ischemia and better presenting and final visual acuities. Reduced perfusion in retinal capillaries with altered retinal vascular anatomy or arteriovenous shunts could be probable reasons for the development of this FA finding. Presence of aberrant filling of the retinal vein could indicate better final visual prognosis.

Artificial intelligence in retinal image analysis: Development, advances, and challenges

Modern advances in diagnostic technologies offer the potential for unprecedented insight into ophthalmic conditions relating to the retina. We discuss the current landscape of artificial intelligence in retina with respect to screening, diagnosis, and monitoring of retinal pathologies such as diabetic retinopathy, diabetic macular edema, central serous chorioretinopathy, and age-related macular degeneration. We review the methods used in these models and evaluate their performance in both research and clinical contexts and discuss potential future directions for investigation, use of multiple imaging modalities in artificial intelligence algorithms, and challenges in the application of artificial intelligence in retinal pathologies.

Progress in central retinal artery occlusion: a narrative review

Central retinal artery occlusion (CRAO) is a catastrophic ophthalmic emergency that severely impairs a patient's visual function, often reducing visual acuity to counting fingers or worse. Progress in CRAO research has provided new information regarding its epidemiological characteristics and led to useful assessments through various ophthalmic examinations. Additional insights about CRAO have been gained through studies of its pathophysiological mechanisms, improving intervention timing and enhancing patient prognosis. Treatment for CRAO has evolved, particularly with assistance from surgical instruments and surgical robots. Although surgical treatment is now possible, this option is not widely recognized by ophthalmologists. Conservative therapies have limited benefits compared with the natural course of disease. Recently, pars plana vitrectomy plus endovascular surgery has received considerable interest among ophthalmologists because of its potential efficacy in the treatment of CRAO. Considering the inconsistencies in rationale and efficacy of CRAO treatment modalities, it is important to distinguish between treatment effects and the natural courses of various CRAO subclasses. This narrative review explores progress in CRAO epidemiology, pathophysiology, ophthalmic examination, and treatment.

Mid-phase pinpoint hyperfluorescent spots on fundus fluorescein angiography in acute central retinal artery occlusion - a novel imaging finding

PURPOSE

To describe the development and outcome of mid-phase pinpoint hyperfluorescent spots (MPHS) on fundus fluorescein angiography (FFA) in acute (< 7-day symptom onset) central retinal artery occlusion (CRAO) patients.

METHODS

This retrospective study included acute CRAO patients who underwent multimodal imaging utilizing optical coherence tomography (OCT) and FFA between June 2017 and January 2023. The correlation of FFA images with the OCT images in various stages and severity of CRAO were studied.

RESULTS

Twenty-three FFA studies on 23 patients with acute CRAO were included. In 11 (48%) cases, an important finding noted on FFA was the presence of single or multiple MPHS with adjacent minimal late vascular leakage. Of these 11 cases, eight (73%) were males and median age was 41 years (inter quartile range: 33-55 years). Visual acuity ranged from 'light perception' to 6/18, and these patients presented anytime on the same day to seven days after symptom onset. On OCT, three eyes had severe CRAO, seven eyes had moderate CRAO, and one eye had mild CRAO. MPHS were primarily observed at the posterior pole and more frequently observed in moderate CRAO severity. During follow-up, the MPHS and retinal vessel staining on FFA disappeared as the CRAO showed signs of resolution.

CONCLUSION

MPHS at the posterior pole on FFA in acute CRAO patients could indicate a more severe occlusion and poor visual outcomes, even after treatment. This finding is most likely caused by red blood cell aggregation or rouleaux formation.

TRIAL REGISTRATION NUMBER

Not applicable.

Imaging in retinal vascular disease: A review

Retinal vascular diseases represent a broad field of ocular pathologies. Retinal imaging is an important tool for diagnosis, prognosis and follow up of retinal vascular diseases. It includes a wide variety of imaging techniques ranging from colour fundus photography and optical coherence tomography to dynamic diagnostic options such as fluorescein angiography, and optical coherence tomography angiography. The newest developments in respective imaging techniques include widefield imaging to assess the retinal periphery, which is of especial interest in retinal vascular diseases. Automatic image analysis and artificial intelligence may support the image analysis and may prove valuable for prognostic purposes. This review provides a broad overview of the imaging techniques that have been used in the past, today and maybe in the future to stage and monitor retinal vascular disease with focus on the main disease entities including diabetic retinopathy, retinal vein occlusion, and retinal artery occlusion.

Analysis on application effects of RAID quality improvement model in closed-loop management of central retinal artery occlusion nursing

OBJECTIVE

This study aimed to analyze the clinical value of applying RAID quality improvement model in closed-loop management of central retinal artery occlusion (CRAO) nursing.

METHODS

Twelve ophthalmic nurses were trained. Soon afterwards, their related knowledge, operation and scene simulation test scores before and after training were examined and compared. Before and after training, 20 CRAO patients who admitted to the second ward of ophthalmology (Ophthalmology Section 2) of our hospital were included into control group and research group. The former applied routine management, while the latter employed RAID quality improvement model.

RESULTS

Before intervention, the ESCA scores and the time window of first-aid of the two groups had no significant difference (all P>0.05). While after intervention, the scores of the research group were dramatically improved; the self-care skills, health knowledge, self-responsibility and self-awareness were obviously higher than those of the control group (all P<0.05); the time window of first-aid in the research group was remarkably shorter than that before intervention, dramatically higher than that in the control group (32.34±8.14 vs. 49.46±8.13; P<0.05). After nursing, the overall satisfaction of patients in the research group (95.00%) was higher than that in the control group (70.00%; P<0.05). Meanwhile, compared with those before training, the examination scores of related knowledge and skills of ophthalmic nurses after training were obviously improved (all P<0.05). The incidence of complications in the research group was 5.00%, while that in the control group was 30.00%. The indexes in the research group were lower than those in the control group, with statistically remarkable differences (P<0.05).

CONCLUSION

RAID quality improvement model is effective in closed-loop management of CRAO nursing, which can effectively improve the quality of nursing for specific diseases and control related indicators. Hence, it's worthy to be promoted.

Indocyanine green angiography imaging findings in artery occlusions

PURPOSE

To describe the multimodal imaging features including indocyanine green angiography (ICGA) in cases diagnosed clinically as central retinal artery occlusion (CRAO) at its different disease stages.

METHODS

In this retrospective observational study, patients diagnosed clinically as CRAO or hemi-CRAO were included. All patients underwent multimodal imaging with optical coherence tomography (OCT), fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were studied. Analysis of ICGA images in different stages of artery occlusions and its correlation with accompanying FFA and OCT images was done.

RESULTS

Eight such studies in five patients were available for analysis. The most important observation noted on ICGA was the presence of hypercyanescent spots seen during the acute stages of the disease in four of the five cases. The spots were accompanied by retinal vessel staining on FFA in the corresponding region. As the disease showed signs of resolution, the hypercyanescent spots on ICGA and retinal vessel staining on FFA disappeared. The hypercyanescent spots seen on the ICGA were noted due to the red blood cell aggregation or 'rouleaux' formation. In addition, choroidal perfusion abnormalities were noted on ICGA in all five cases in the acute stage.

CONCLUSION

Choroidal perfusion changes can be identified in acute phase of retinal artery occlusion. Rouleaux formation in the retinal circulation occurs due to the slowing of the blood flow following artery occlusion. These are seen as hypercyanescent spots in the late phase on ICGA.

Efficacy of intravitreal injection of conbercept on non-proliferative diabetic retinopathy: a retrospective study

Objective

This study assessed the efficacy of conbercept for patients with non-proliferative diabetic retinopathy (NPDR).

Methods

In this retrospective clinical study, 54 patients with NPDR (54 eyes) were treated with intravitreal injection of conbercept using a 3+ pro re nata regimen and followed up for 12 months. Best corrected visual acuity (BCVA), central foveal thickness (CFT), area of hard exudate (HE), and number of microaneurysms (MAs) were used as indicators of therapeutic effects. Systemic adverse reactions were recorded to assess safety.

Results

During the 12-month follow-up period, the mean number of injections was 6.12 ± 1.89 on demand. From baseline to the 12-month follow-up, the BCVA of patients with NPDR increased from 0.71 ± 0.20 logMAR to 0.43 ± 0.16 logMAR, CFT decreased from 424.26 ± 64.89 μm to 269.27 ± 44.79 μm, and the number of MAs declined from 79.53 ± 27.18 to 33.34 ± 16.53. Moreover, the area of HE was significantly reduced after 9 months of treatment. There were no serious systemic adverse events during the follow-up.

Conclusions

Intravitreal injection of conbercept has a stable and robust effect on patients with NPDR over a 12-month follow-up period. Thus, conbercept is an effective and feasible treatment for NPDR.

Non-invasive measurement of retinal permeability in a diabetic rat model

OBJECTIVE

The gold standard for measuring blood-retinal barrier permeability is the Evans blue assay. However, this technique has limitations in vivo, including non-specific tissue binding and toxicity. This study describes a non-toxic, high-throughput, and cost-effective alternative technique that minimizes animal usage.

METHODS

Sodium fluorescein fundus angiography was performed in non-diabetic and diabetic Brown Norway rats on days 0, 7, 14, 21, and 28. Sodium fluorescein intensity in the retinal interstitium and a main retinal vessel were measured over time. The intensity gradients were used to quantify retinal vascular permeability. Post-study eyes were fixed, dissected, and stained (isolectin B4) to measure required parameters for permeability quantification including total vessel length per retinal volume, radius, and thickness.

RESULTS

In the non-diabetic cohort retinal permeability remained constant over the 28-day study period. However, in the diabetic cohort there was a significant and progressive increase in retinal permeability from days 14-28 (P < .01, P < .001, P < .0001).

CONCLUSIONS

This novel imaging methodology in combination with mathematical quantification allows retinal permeability to be non-invasively and accurately measured at multiple time points in the same animal. In addition, this technique is a non-toxic, rapid, sensitive, and cost-effective alternative to the Evans blue assay.

Multimodal Imaging of Acute Central Retinal Artery Occlusion

The aim of this study was to describe fluorescein angiography (FA), ocular coherence tomography (OCT) and ocular coherence tomography angiography (OCTA) in the diagnosis of acute central retinal artery occlusion (CRAO). This is an observational case series study performed at Sohag Ophthalmic Investigation Center. Fifteen patients presented by a sudden marked unilateral diminution of vision were included. Corrected Distance Visual acuity (CDVA), color fundus photos, FA, OCT and OCTA, imaging obtained in the first week of presentation and imaging of the other normal eye as a control were assessed. Central macular thickness (CMT), parafoveal inner retinal layers thickness and parafoveal outer retinal thickness in diseased and contralateral normal eyes were compared. Fifteen patients (mean age 52.67 years, 11-74 years old) including 66.7% male entered the study. CDVA ranged from no perception of light to 0.05 (20/400). Fundus examination showed a cherry red spot in 10 cases (66.7 %) and retinal whitening in 9 cases (60%), arteriolar narrowing in 7 (46.67%), optic disc edema in 4 (26.67%), optic disc pallor in 5 (33.3%) and cattle trucking in 5 (33.3%). Fluorescein angiography showed delayed arteriovenous transit time > 23 seconds in 8 cases (53.33 %) and normal FA in 4 cases (26.67 %). OCT revealed increased hyperreflective of the inner retinal layers in comparison to hyporeflective inner retinal layers in all cases (100%) and significant increase in CMT in 10 cases (66.67%). The mean ± standard deviation (SD) of CMT (CRAO) was 306.5 ± 27.9 (P < 0.001), the parafoveal inner retinal thickness (CRAO) 345 ± 51.8 µm (P < 0.001) and the parafoveal outer retinal thickness (CRAO) 120.9 ± 13.6 µm (P < 0.001). OCTA was performed and clear images obtained in 11 cases (73.33%). Disruption of superficial and deep capillary plexus was found in all cases. We concluded that the OCT is the most confirmative imaging method in the diagnosis of acute CRAO even in the absence of fundus signs. OCTA confirms the diagnosis, but it cannot be performed in some cases.

The Utility of Fundus Fluorescein Angiography in Neuro-Ophthalmology

While its use is still widespread within the medical retina field, fundus fluorescein angiography (FFA) is increasingly falling out of favour in the investigation of neuro-ophthalmological disease, with the introduction of new technologies, particularly optical coherence tomography. FFA does, however, provide useful diagnostic and prognostic information in many neuro-ophthalmological diseases including papilloedema, pseudo-papilloedema, optic neuropathies and central retinal artery occlusion to name a few. We aim to summarise the main FFA findings in each of these conditions and highlight where FFA is of most use in providing complementary information to other modes of investigation.

Detection of microvascular retinal changes in type I diabetic mice with optical coherence tomography angiography

Optical coherence tomography (OCT) angiography is a dye-free and non-invasive angiography which allows visualization of retinal and choroid vascular flow, enabling observation of highly permeable and three dimensional vasculature. Although OCT angiography is providing new insights in human retinal and choroidal diseases, a few studies have been reported in experimental mice. In this study, to determine the potential of OCT angiography in experimental mice, we sought to examine whether OCT angiography can detect vascular change in type I diabetic mice. To conduct age dependent analysis, 2 and 6 month old male type 1 diabetic Ins2^Akita/+ and age matched C57BL/6J mice were used. OCT angiography was performed by Heidelberg Spectralis OCT Angiography Module with 30° lens + mouse adapter lens. We acquired the OCT angiography image from the peripheral nasal position. For analysis of OCT angiography images, OCT angiography positive area were used for vascular density. We analyzed vascular density from the retinal surface (inner limiting membrane) to 120 μm depth with 4 μm steps in order to correlate vascular density vs depth (N = 4 per group). Vascular density of both mouse strains demonstrated three different peaks. By comparing with the OCT image, the first peak (superficial), second peak (intermediate) and third peak (deep) were located in nerve fiber layer/ganglion cell layer, inner plexiform layer/inner nuclear layer and outer plexiform layer/outer nuclear layer, respectively. We calculated vascular density of these peaks separately. In C57BL/6J mice, the vascular density in all three layers do not show significant difference between 2- and 6-month-old. On the other hand, 6-month-old Ins2^Akita/+ mice showed a significant decrease of the vascular density in all three layers compared to 2-month-old Ins2^Akita/+ mice. Also, the vascular density of 6-month-old Ins2^Akita/+ mice in the deep layer showed a significant decrease compared to 2- and 6-month-old C57BL/6J mice. Thus, OCT angiography successfully detects retinal vascular difference between type I diabetic mice and control mice, and age-dependent vasculature change in type I diabetic mice. The diabetic mice demonstrated reduced vascular density due to reduced density of flowing deep vessels. Importantly, we observed this difference without retinal blood leakage, hemorrhage or neovascularization. Our analysis (vascular density vs retinal depth) suggests that OCT angiography is useful for in vivo detection of retinal vasculature alteration in experimental mice.

Automatic measurement of global retinal circulation in fluorescein angiography

Examination of the retinal circulation in patients with retinal diseases is a clinical routine for ophthalmologists. In the present work, an automatic method is proposed for measuring the global retinal circulation in fluorescein angiography (FA). First, the perfusion region in FA images is segmented using a multiscale line detector. Then, the time evolution of the perfusion area is modeled using damped least-squares regression. Based on the perfusion area profile, some circulation parameters are defined to describe quantitatively the global retinal circulation. The effectiveness of the proposed method is tested using our own and public datasets, with reasonable results and satisfactory accuracy compared with manual measurement. The proposed method has good computing efficiency and thus has potential to be used in clinical practice for evaluation of global retinal circulation.

Central Retinal Artery Occlusion: Acute Management and Treatment

PURPOSE OF REVIEW

This review will seek to answer if advances in ophthalmic imaging and evolution of treatment modalities have shed further light on the epidemiology, pathophysiology, diagnosis, and acute management of acute CRAO.

RECENT FINDINGS

Imaging characteristics of acute CRAO have been further characterized with the use of fluorescein angiography, optical coherence tomography (OCT), OCT-angiography, and indocyanine-green angiography. Layer segmentation of OCT imaging has found inner retinal layer hyper-reflectivity to be a common finding in acute CRAO. Non-invasive therapies, fibrinolytic delivery, and surgical interventions for acute CRAO have been further evaluated as potential management tools.

SUMMARY

A large body of literature reports very inconsistent treatment success with a wide variety of modalities. Currently, there is no clear evidence supporting the use of fibrinolytics in acute CRAO. Large, multicenter, randomized control trials are necessary to elucidate the role of the various acute treatment options in the management of CRAO.