Local intra-arterial fibrinolysis for acute occlusion of the central retinal artery: a meta-analysis of the published data

Management of vision loss associated with complications of cosmetic filler injections

Injectable cosmetic fillers have dramatically risen in popularity in recent years. However, as the use of such fillers has become more common, there have been many reports of vision loss secondary to misplaced filler embolizing to the ophthalmic artery resulting in ocular ischemia. Currently, there are no randomized control trials or widely validated clinical guidelines that dictate how injectors should manage ischemic complications of filler embolism. This review aims to explain the possible mechanisms by which a cosmetic filler embolus can occlude the ophthalmic artery, describe the types of treatments that have been attempted thus far, and delineate possible a stroke-like protocol that can be implemented in order to restore perfusion and recover vision after such ischemic complications have occurred.

Efficacy and safety of intra-arterial thrombolysis in patients with central retinal artery occlusion: a systematic review and meta-analysis

PURPOSE

To investigate the efficacy and safety of intra-arterial thrombolysis (IAT) in patients with central retinal artery occlusion (CRAO).

METHODS

PubMed and EMBASE were searched for potentially eligible studies that reported IAT in CRAO patients from inception to Nov 8, 2021. Standard mean difference (SMD) was pooled to compare visual acuity (VA) at baseline with final in IAT patients. The rates and odds ratios (OR) were meta-analyzed to compare VA improvement in IAT with non-IAT patients, stratified to different times from onset to procedure, different definitions of VA improvement, and three CRAO stages. Adverse effects were recorded.

RESULTS

Fifteen studies were included, enrolling 507 CRAO patients who received IAT and 296 CRAO patients who did not. VA was significantly improved from baseline to final VA in IAT patients (SMD [LogMAR] 0.70, 95% CI [0.51, 0.90]). VA improvement rate was higher in IAT patients than that in non-IAT (56% vs 32%, OR 3.55, 95%CI [1.74, 7.24]), with greater OR in IAT within 6 h from onset to procedure (OR 4.60, 95%CI [1.24, 16.99]) than that beyond 6 h (OR 3.36, 95%CI [1.43, 7.85]). The benefit remained consistent when VA improvement was defined as ≥ 3 lines on the Snellen chart (OR 4.68, 95%CI [2.10, 10.41]) and was even greater when CRAO was incomplete. Five patients had a symptomatic intracranial hemorrhage and 21 patients had ischemic stroke or transient ischemic attack after IAT.

CONCLUSIONS

IAT treatment has certain potential in ameliorating VA in CRAO patients, which should be balanced against cerebral complications.

Risk Factors and Treatment Strategy for Retinal Vascular Occlusive Diseases

Retinal occlusive diseases are common diseases that can lead to visual impairment. Retinal artery occlusion and retinal vein occlusion are included in the clinical entity, but they have quite different pathophysiologies. Retinal artery occlusion is an emergent eye disorder. Retinal artery occlusion is mainly caused by thromboembolism, which frequently occurs in conjunction with life-threatening stroke and cardiovascular diseases. Therefore, prompt examinations and interventions for systemic vascular diseases are often necessary for these patients. Retinal vein occlusion is characterized by retinal hemorrhage and ischemia, which may impair visual function via several complications such as macular edema, macular ischemia, vitreous hemorrhage, and neovascular glaucoma. Even though anti-vascular endothelial growth factor therapy is the current established first-line of treatment for retinal vein occlusion, several clinical studies have been performed to identify better treatment protocols and new therapeutic options. In this review, we summarize the current findings and advances in knowledge regarding retinal occlusive diseases, particularly focusing on recent studies, in order to provide an update for a better understanding of its pathogenesis.

Safety and Efficacy of Selective Intra-arterial Thrombolysis for Central Retinal Artery Occlusion

PURPOSE

The purpose of this study was to determine the efficacy and safety of selective intra-arterial thrombolysis in patients with central retinal artery occlusion (CRAO).

METHODS

Medical records for 44 eyes of 44 patients diagnosed with acute non-arteritic CRAO and thrombolysis between October 2010 and February 2019 were analyzed retrospectively. Based on visual acuity, fundoscopic findings, and fluorescein angiography, the patients were classified into three stages: incomplete, subtotal, and total. The perfusion state using the best-corrected visual acuity (BCVA), arm to retina time, and arteriovenous passage times, after 1 month, 6 months, and at the final visit after the procedure, were compared with baseline readings.

RESULTS

Improvement of visual acuity was confirmed in 31 out of 44 patients (70.45%). The mean BCVA of 44 patients changed from 1.65 ± 0.78 logarithmic minimum angle of resolution (logMAR) at the first visit to 1.18 ± 0.91 logMAR at the last visit (p = 0.114). The BCVA according to CRAO stage was 0.08 ± 0.11 logMAR for the incomplete stage at the first visit, 0.06 ± 0.05 logMAR (p = 0.933) 1 month after the procedure, and 0.05 ± 0.07 logMAR (p = 0.933) at the last visit. In the subtotal stage, the results were 1.81 ± 0.54 logMAR at the first visit, 1.63 ± 0.76 logMAR (p = 0.035) 1 month after the procedure, and 1.36 ± 0.85 logMAR (p = 0.014) at the last visit. For the total stage of BCVA, the result at the first visit was 2.36 ± 0.25 logMAR, and it was 2.30 ± 0.30 logMAR (p = 0.510) 1 month after the procedure, and 2.42 ± 0.30 logMAR (p = 0.642) at the last visit. Reperfusion was observed in 40 patients out of the 44 (90.91%).

CONCLUSIONS

Selective intra-arterial thrombolysis can be helpful in patients with subtotal CRAO in terms of visual improvement and retinal arterial reperfusion.

Iatrogenic ophthalmic artery occlusion and retinal artery occlusion

Iatrogenic ophthalmic artery occlusion (IOAO) is a rare but devastating ophthalmic disease that may cause sudden and permanent visual loss. Understanding the possible etiologic modalities and pathogenic mechanisms of IOAO may prevent its occurrence. There are numerous medical etiologies of IOAO, including cosmetic facial filler injection, intravascular procedures, intravitreal gas or drug injection, retrobulbar anesthesia, intraarterial chemotherapy in retinoblastoma. Non-ocular surgeries and vascular events in arteries that are not directly associated with the ophthalmic artery, can also cause IOAO. Since IOAO has a limited number of treatment modalities, which lead to poor final visual prognosis, it is imperative to acknowledge the information regarding medical procedures that are etiologically associated with IOAO. We accumulated all searchable and available IOAO case reports (our cases and previous reported cases from the literature), classified them according to their mechanisms of pathogenesis, and summarized treatment options and responses of each of the causes. Various sporadic cases of IOAO can be categorized into three mechanisms as follows: intravascular event, orbital compartment syndrome, and increased intraocular pressure. Embolic IOAO, which is considered the primary cause of the condition, was classified into three subgroups according to the pathway of embolic movement (retrograde pathway, anterograde pathway, pathway through collateral channels). Despite the practical limitations of treating spontaneous (non-iatrogenic) retinal artery occlusion, this article will contribute in predicting and improving the prognosis of IOAO by recognizing the treatable factors. Furthermore, it is expected to provide clues to future research associated with the treatment of retinal artery occlusion.

Characteristics and Outcomes of Retinal Artery Occlusion: Nationally Representative Data

Background and Purpose- There are few large studies examining comorbidities, outcomes, and acute interventions for patients with retinal artery occlusion (RAO). RAO shares pathophysiology with acute ischemic stroke (AIS); direct comparison may inform emergent treatment, evaluation, and secondary prevention. Methods- The National Readmissions Database contains data on ≈50% of US hospitalizations from 2013 to 2015. We used International Classification of Diseases, Ninth Revision, codes to identify and compare index RAO and AIS admissions, comorbidities, and interventions and Clinical Comorbidity Software codes to identify readmissions causes, using survey-weighted methods when possible. Cumulative risk of all-cause readmission after RAO ≤1 year was estimated by Kaplan-Meier analysis. Results- Among 4871 RAO and 1 239 963 AIS admissions, patients with RAO were less likely (P<0.0001) than patients with AIS to have diabetes mellitus (RAO, 24.3% versus AIS, 36.8%), congestive heart failure (9.1% versus 14.8%), atrial fibrillation (15.5% versus 25.2%), or hypertension (62.2% versus 67.6%) but more likely to have valvular disease (13.3% versus 10.5%) and tobacco usage (38.6% versus 32.9%). In RAO admissions, thrombolysis was administered in 2.9% (5.8% in central RAO subgroup, versus 8.0% of AIS), therapeutic anterior chamber paracentesis in 1.0%, thrombectomy in none; 1.4% received carotid endarterectomy during index admission, 1.6% within 30 days. Nearly 1 in 10 patients with RAO were readmitted within 30 days and were more than twice as likely as patients with AIS to be readmitted for dysrhythmia or endocarditis. Readmission for stroke after RAO was the highest within the first 150 days after index admission, and risk was higher in central RAO than in branch RAO. Conclusions- Patients with RAO had high prevalence of many stroke risk factors, particularly valvular disease and smoking, which can be addressed to minimize subsequent risk. Despite less baseline atrial fibrillation, RAO patients were more likely to be readmitted for atrial fibrillation/dysrhythmias. A variety of interventions was administered. AIS risk is the highest shortly after RAO, emphasizing the importance of urgent, thorough neurovascular evaluation.

Intra-Arterial Thrombolysis for Central Retinal Artery Occlusion

Introduction

Central retinal artery occlusion is an ophthalmic emergency which typically causes acute, painless visual loss. Several conservative treatment options are practiced with little benefit. Thrombolysis as a therapeutic option has gathered interest as well as controversy. This paper aims at reviewing the relevant literature to assess the efficacy and safety of intra-arterial thrombolysis for acute central retinal artery occlusion.

Methods

A review of the literature was conducted. Keywords included “intra-arterial thrombolysis” or “intra-arterial fibrinolysis” in combination with “central retinal artery occlusion” or “CRAO”. A Cochrane Database search was performed for randomised control trials, systematic reviews and meta-analyses using the same keywords.

Results

Twenty-eight studies were identified which included case reports, case series, case-control studies and 1 randomised control trial: the European Assessment Group for Lysis in the Eye Study. Improvement in vision was measured using different methods and at different time points. The findings of these studies generally favour an effect towards intra-arterial thrombolysis however there are many limitations. Additionally, the European Assessment Group for Lysis in the Eye Study showed lack of effect in intra-arterial thrombolysis vs conservative measures.

Conclusion

Current evidence is not sufficient to recommend intra-arterial thrombolysis due to the variability of visual improvement within retrospective studies, heterogeneity in treatment regimens between studies and adverse effects. Intra-arterial thrombolysis may have a role in patients presenting early, particularly if they have monocular vision, after discussion of the risks and benefits. Further high-quality trials assessing the clinical efficacy of intra-arterial thrombolysis may shed more light on this topic.

Central retinal artery occlusion-A new, provisional treatment approach

The retinal ganglion cells infarcted in central retinal artery occlusion (CRAO) are the somata of the optic nerve axons, part of the central nervous system. Consequently, CRAO with inner retinal infarction is a small vessel stroke, usually with the devastating consequence of severe visual loss in the affected eye. At present, there is no generally accepted, evidence-based therapy of nonarteritic CRAO in contrast to ischemic cerebral stroke that has well-accepted treatment protocols. Widely divergent and controversial therapeutic options for CRAO reflect the desperation of treating physicians and disparate conflicting studies. We examine reasons why treatment of nonarteritic CRAO remains problematic and then suggest a provisional new approach to treatment based on updated understanding of CRAO pathophysiology and analysis of current therapeutic options and their rationales.

Central retinal artery occlusion

The pathogeneses, clinical features, and management of central retinal artery occlusion (CRAO) are discussed. CRAO consists of the following four distinct clinical entities: non-arteritic CRAO (NA-CRAO), transient NA-CRAO, NA-CRAO with cilioretinal artery sparing, and arteritic CRAO. Clinical characteristics, visual outcome, and management very much depend upon the type of CRAO. Contrary to the prevalent belief, spontaneous improvement in both visual acuity and visual fields does occur, mainly during the first 7 days. The incidence of spontaneous visual acuity improvement during the first 7 days differs significantly (P < 0.001) among the four types of CRAO; among them, in eyes with initial visual acuity of counting finger or worse, visual acuity improved, remained stable, or deteriorated in NA-CRAO in 22%, 66%, and 12%, respectively; in NA-CRAO with cilioretinal artery sparing in 67%, 33%, and none, respectively; and in transient NA-CRAO in 82%, 18%, and none, respectively. Arteritic CRAO shows no change. Recent studies have shown that administration of local intra-arterial thrombolytic agent not only has no beneficial effect but also can be harmful. Investigations to find the cause and to prevent or reduce the risk of any further visual problems are discussed. Prevalent multiple misconceptions on CRAO are discussed.

Central retinal artery occlusion secondary to Barlow's disease

PURPOSE

To report a rare case of isolated, unilateral CRAO in a young patient with mitral valve prolapse secondary to Barlow's disease.

OBSERVATIONS

A 29-year-old woman with history of premature ventricular contractions and cardiac ablation presented to the emergency room after sudden onset painless visual loss in her left eye (OS). Her vision was 20/20 in her right eye and hand motion in the left. Fundus exam demonstrated a central retinal artery occlusion (CRAO) OS. Computerized tomography of head and neck were unremarkable. She underwent cerebral angiogram and local intra-arterial thrombolysis. Her vision remained stable post-procedure, with marked APD and stable fundus examination. Her cardiac work-up revealed a left atrial mass with calcified mitral valve, and small atrial septal defect. Rheumatologic, hematologic, and auto-immune work-up were unremarkable. She underwent resection of the mass with repair of mitral valve and ASD closure. Surgical pathology was compatible with diagnosis of Barlow's disease, a cause of mitral valve prolapse. The patient underwent intravitreal injection of anti-VEGF therapy at one month follow-up, with vision stable at hand motion and without neovascularization on subsequent evaluation.

CONCLUSIONS

In young patients presenting with CRAO, aggressive work-up for systemic disease or embolic source must be undertaken to avoid future sequelae.

Intra-Arterial Thrombolysis for Acute Central Retinal Artery Occlusion: A Systematic Review and Meta-Analysis

Background and purpose

Acute central retinal artery occlusion (CRAO) is a serious ophthalmologic emergency that may result in monocular blindness. To date, studies evaluating intra-arterial thrombolysis (IAT) have not shown a definitive clinical benefit. We have conducted a systematic review with a meta-analysis to effectively evaluate this treatment option.

Methods

A systematic literature search was focused on studies containing five or more patients undergoing IAT that included a control group treated with standard therapy. Pooled meta-analysis was performed.

Results

Five retrospective controlled studies and one randomized clinical trial were identified satisfying all inclusion criteria resulting in the analysis of 236 patients treated with IAT and 255 patients treated with ST. A pooled fixed effects analysis resulted in an estimated odds ratio of 2.52, 95% CI (1.69, 3.77) (P < 0.0001) favoring IAT.

Conclusion

IAT is a promising therapeutic option for CRAO with great potential. Further randomized trials are needed to establish a significant benefit and ensure the safety of the intervention.

Endovascular Management of Central Retinal Arterial Occlusion

BACKGROUND AND IMPORTANCE

Central retinal artery occlusion (CRAO) is an ophthalmologic emergency due to the sudden cessation of circulation to the inner retinal layer. Without immediate treatment, permanent blindness may ensue. Several treatment options exist, ranging from noninvasive medical management to thrombolysis. Nonetheless, ongoing debate exists regarding the best therapeutic strategy.

CASE PRESENTATION

The authors present the case of a 78-year-old woman with a medical history of hypercholesterolemia and rheumatoid arthritis who experienced complete loss of vision in her left eye. Following ophthalmologic evaluation demonstrating left CRAO, anterior chamber paracentesis was performed. Endovascular intervention was performed via local intra-arterial fibrinolysis with alteplase. Her vision returned to 20/20 following the procedure. In general, conventional therapies have not significantly improved patient outcomes.

CONCLUSION

Several management options exist for CRAO. In general, conservative measures have not been reported to yield better patient outcomes as compared to the natural history of this medical emergency. Endovascular approaches are another option as observed with this case reported. In cases of CRAO, therapeutic strategies such as intra-arterial fibrinolysis utilize a local infusion of reactive tissue plasminogen activator directly at the site of occlusion via catheterization of the ophthalmic artery. Although several case series do show promising results after treating CRAO with intra-arterial fibrinolysis, further studies are required given the reports of complications.

Intra-arterial Thrombolysis for Retinal Artery Occlusion: The Calgary Experience

Introduction:

Retinal artery occlusion represents a medical emergency with poor prognosis for visual recovery. Spontaneous improvement is estimated to occur in less than 15% of central retinal artery occlusion (CRAO) cases and conventional treatments have provided only limited benefit. Intra-arterial thrombolysis has been reported as a potentially efficacious and safe treatment.

Methods:

We performed a retrospective chart review of all retinal artery occlusion cases treated with intra-arterial recombinant tissue-type plasminogen activator (rtPA) from January 1998 to May 2004. Patients received Goldmann perimetry visual field testing at a variable interval following the procedure (2 days-2.5 years). Visual acuity (VA) was re-assessed in May 2004.

Results:

Eight cases (59-77 years) were treated for CRAO, 6-18 hours post-onset with intra-arterial rtPA (10-20 mg over 15-60 minutes); one case of branch occlusion (BRAO) was treated with 30 mg rtPA over 75 minutes, 12 hours post-onset. Among the six patients with CRAO assessed in clinic, three experienced improvement in VA by two or more gradations (Snellen lines); three improved by one gradation. However, none achieved a final VA better than 20/300. The case of branch occlusion improved to a VA of 20/20. All patients had residual monocular field defects.

Conclusion:

Our findings reveal a limited benefit for intra-arterial tPA compared to the rate of spontaneous improvement and conventional forms of therapy for retinal artery occlusion.

Evaluation of Ophthalmic Artery Branch Retrograde Intervention in the Treatment of Central Retinal Artery Occlusion (CRAO)

BACKGROUND Central retinal artery occlusion (CRAO) is the occlusion of the central retinal artery resulting in retinal infarction and acute vision loss. Digital subtraction angiography (DSA)-guided superselective ophthalmic artery or selective carotid thrombolysis remains the preferred treatment method for CRAO. This study aimed to evaluate the safety and clinical efficacy of the novel ophthalmic artery branch retrograde thrombolytic intervention for CRAO. MATERIAL AND METHODS Fifty patients with monocular CRAO were enrolled, including 28 males and 22 females (mean age: 55.7±2.3 years). The patients were randomly divided into two groups for thrombolysis with urokinase (400,000 U) and papaverine (30 mg) by either ophthalmic artery branch retrograde intervention (group A, n=26) or superselective ophthalmic artery/selective carotid intervention (group B, n=24). There was no significant difference in age (P=0.58), gender ratio (P=0.49), and time to onset (P=1.00) between the two groups. The adverse reactions and clinical efficacy were evaluated by postoperative DSA, fundus fluorescein angiography (FFA), and visual acuity tests. RESULTS No serious complications, abnormal eye movement, or vitreous hemorrhage occurred in either group. DSA showed that group A had an effective rate (92.30%) comparable to that of group B (100%, χ²=2.08, P=0.25). FFA suggested that both groups had similar treatment efficacy (χ²=3.09, P=0.21). Visual acuity tests also confirmed a similar efficacy of the two intervention approaches (χ²=0.25, P=0.88). CONCLUSIONS The developed novel ophthalmic artery branch retrograde intervention is highly effective and safe for CRAO, and may be a superior method compared with the conventional approach.

Central Retinal Artery Occlusion after the Endovascular Treatment of Unruptured Ophthalmic Artery Aneurysm: A Case Report and a Literature Review

Endovascular coil embolization for ophthalmic artery (OphA) aneurysms has a risk of occlusion of the OphA, which can lead to loss of vision. The authors report a patient with unruptured OphA aneurysm which treated with endovascular coiling and were complicated by blindness due to OphA thromboembolic occlusion after the procedure. The OphA successfully recanalized using local intra-arterial fibrinolysis with complete regain of visual acuity. The risk of visual loss due to thromboembolic complications cannot be ignored during endovascular coiling of the OphA aneurysm despite of good retrograde flow during OphA occlusion test using a balloon catheter. Rapid intervention is required for recovering visual disturbance in such a situation.

Hypothermia Protects and Prolongs the Tolerance Time of Retinal Ganglion Cells against Ischemia

Purpose

Hypothermia has been shown to be neuroprotective in the therapy of ischemic stroke in the brain. To date no studies exist on the level of the inner retina and it is unclear if hypothermia would prolong the ischemic tolerance time of retinal ganglion cells, which are decisive in many ischemic retinopathies.

Methods

Bovine eyes were enucleated and stored either at 21°C or 37°C for 100 or 340 minutes, respectively. Afterwards the globes were dissected, the retina was prepared and either the spontaneous ganglion cell responses were measured or the retina was incubated as an organotypic culture for additional 24 hours. After incubation the retina was either processed for histology (H&E and DAPI staining) or real-time PCR (Thy-1 expression) was performed.

Results

Hypothermia prolonged ganglion cell survival up to 340 minutes under ischemic conditions. In contrast to eyes kept at 37°C the eyes stored at 21°C still showed spontaneous ganglion cell spiking (56.8% versus 0%), a 5.8 fold higher Thy-1 mRNA expression (not significant, but a trend) and a preserved retinal structure after 340 minutes of ischemia.

Conclusion

Hypothermia protects retinal ganglion cells against ischemia and prolongs their ischemic tolerance time.

Evidence for an enduring ischaemic penumbra following central retinal artery occlusion, with implications for fibrinolytic therapy

The rationale behind hyperacute fibrinolytic therapy for cerebral and retinal arterial occlusion is to rescue ischaemic cells from irreversible damage through timely restitution of tissue perfusion. In cerebral stroke, an anoxic tissue compartment (the "infarct core") is surrounded by a hypoxic compartment (the "ischaemic penumbra"). The latter comprises electrically-silent neurons that undergo delayed apoptotic cell death within 1-6 h unless salvaged by arterial recanalisation. Establishment of an equivalent hypoxic compartment within the inner retina following central retinal artery occlusion (CRAO) isn't widely acknowledged. During experimental CRAO, electroretinography reveals 3 oxygenation-based tissue compartments (anoxic, hypoxic and normoxic) that contribute 32%, 27% and 41% respectively to the pre-occlusion b-wave amplitude. Thus, once the anoxia survival time (≈2 h) expires, the contribution from the infarcted posterior retina is irreversibly extinguished, but electrical activity continues in the normoxic periphery. Inbetween these compartments, an annular hypoxic zone (the "penumbra obscura") endures in a structurally-intact but functionally-impaired state until retinal reperfusion allows rapid recovery from electrical silence. Clinically, residual circulation of sufficient volume flow rate generates the heterogeneous fundus picture of "partial" CRAO. Persistent retinal venous hypoxaemia signifies maximal extraction of oxygen by an enduring "polar penumbra" that permeates or largely replaces the infarct core. On retinal reperfusion some days later, the retinal venous oxygen saturation reverts to normal and vision improves. Thus, penumbral inner retina, marginally oxygenated by the choroid or by residual circulation, isn't at risk of delayed apoptotic infarction (unlike hypoxic cerebral cortex). Emergency fibrinolytic intervention is inappropriate, therefore, once the duration of CRAO exceeds 2 h.

Current endovascular treatment options for central retinal arterial occlusion: a review

Central retinal artery occlusion, although relatively rare, is an ophthalmological emergency. If left untreated, complete blindness will ensue. Conventional therapies have not significantly improved outcomes compared with the natural history of the disease. Several case series of more recent endovascular approaches, such as intraarterial fibrinolysis, report successful outcomes. Still other studies regarding intraarterial fibrinolysis do not demonstrate any significantly better outcomes, with some even indicating increased complication rates. Therefore, the authors present a review of the current endovascular treatment options for central retinal artery occlusion.

Transcorneal electrical stimulation in patients with retinal artery occlusion: a prospective, randomized, sham-controlled pilot study

Introduction

The purpose of this study was to investigate the safety and efficacy of transcorneal electrical stimulation (TES) in patients suffering from retinal artery occlusion (RAO).

Methods

Twelve patients with central and one patient with branch RAO (age 25–84 years, median 74 years) were enrolled in this prospective, randomized, sham-controlled study. RAO was diagnosed 10 days to 17 months prior to study participation. Patients were treated with TES (5 ms positive followed by 5 ms negative biphasic pulses at 20 Hz; applied with DTL electrodes) for 30 min once a week for 6 consecutive weeks. Patients were randomly assigned to TES with 0 mA (sham, n = 3), 66% (n = 5) or 150% (n = 5) of the patient’s individual electrical phosphene threshold (EPT) at 20 Hz. Best corrected visual acuity, ophthalmology examination and EPT (at 3, 6, 9, 20, 40, 60, and 80 Hz) were determined at baseline and at eight follow-up visits over 17 weeks. During four visits (week 1, 5, 9, and 17) kinetic and static visual fields as well as full-field and multifocal electroretinography were measured. The method of restricted maximum likelihood (P < 0.05, Tukey–Kramer) was used to estimate the development of parameters under treatment.

Results

TES was tolerated well; no ocular or systemic adverse events were observed except for foreign-body sensation after TES (n = 3). During the study period the slopes of the scotopic a-wave increased significantly (high-intensity flash white 10 cd.s/m²; P = 0.03) in the 150% treatment group. All other parameters in all other groups remained statistically unchanged.

Conclusions

Although TES was tolerated well, statistically significant improvements were found only for specific a-wave slopes. This is in contradiction to previous smaller, uncontrolled reports. Further studies with larger sample sizes and longer duration might, however, show additional significant effects.

Treatment options for central retinal artery occlusion

OPINION STATEMENT

Central retinal artery occlusion (CRAO) is an ocular emergency and is the ocular analogue of cerebral stroke. It results in profound, usually monocular vision loss, and is associated with significant functional morbidity. The risk factors for CRAO are the same atherosclerotic risk factors as for stroke and heart disease. As such, individuals with CRAO may be at risk of ischemic end organ damage such as a cerebral stroke. Therefore, the management of CRAO is not only to restore vision, but at the same time to manage risk factors that may lead to other vascular conditions. There are a number of therapies that has been used in the treatment of CRAO in the past. These include carbogen inhalation, acetazolamide infusion, ocular massage and paracentesis, as well as various vasodilators such as intravenous glyceryl trinitrate. None of these "standard agents" have been shown to alter the natural history of disease definitively. There has been recent interest shown in the use of thrombolytic therapy, delivered either intravenously or intra-arterially by direct catheterisation of the ophthalmic artery. Whilst a number of observational series have shown that the recovery of vision can be quite dramatic, two recent randomised controlled trials have not demonstrated efficacy. On the contrary, intra-arterial delivery of thrombolytic may result in an increased risk of intracranial and systemic haemorrhage, while the intravenous use of tissue plasminogen activator (tPA) was not shown to be efficacious within 24 h of symptom onset. Nevertheless, both of these studies have shown one thing in common, and that is for treatment to be effective in CRAO, it must be deployed within a short time window, probably within 6 h of symptom onset. Therefore, while CRAO is a disease that does not have a treatment, nevertheless it needs to follow the same principles of treatment as any other vascular end organ ischaemic disease. That is, to attempt to reperfuse ischemic tissue as quickly as possible and to institute secondary prevention early.

Acute retinal arterial occlusive disorders

The initial section deals with basic sciences; among the various topics briefly discussed are the anatomical features of ophthalmic, central retinal and cilioretinal arteries which may play a role in acute retinal arterial ischemic disorders. Crucial information required in the management of central retinal artery occlusion (CRAO) is the length of time the retina can survive following that. An experimental study shows that CRAO for 97min produces no detectable permanent retinal damage but there is a progressive ischemic damage thereafter, and by 4h the retina has suffered irreversible damage. In the clinical section, I discuss at length various controversies on acute retinal arterial ischemic disorders. Classification of acute retinal arterial ischemic disorders: These are of 4 types: CRAO, branch retinal artery occlusion (BRAO), cotton wool spots and amaurosis fugax. Both CRAO and BRAO further comprise multiple clinical entities. Contrary to the universal belief, pathogenetically, clinically and for management, CRAO is not one clinical entity but 4 distinct clinical entities - non-arteritic CRAO, non-arteritic CRAO with cilioretinal artery sparing, arteritic CRAO associated with giant cell arteritis (GCA) and transient non-arteritic CRAO. Similarly, BRAO comprises permanent BRAO, transient BRAO and cilioretinal artery occlusion (CLRAO), and the latter further consists of 3 distinct clinical entities - non-arteritic CLRAO alone, non-arteritic CLRAO associated with central retinal vein occlusion and arteritic CLRAO associated with GCA. Understanding these classifications is essential to comprehend fully various aspects of these disorders. Central retinal artery occlusion: The pathogeneses, clinical features and management of the various types of CRAO are discussed in detail. Contrary to the prevalent belief, spontaneous improvement in both visual acuity and visual fields does occur, mainly during the first 7 days. The incidence of spontaneous visual acuity improvement during the first 7 days differs significantly (p<0.001) among the 4 types of CRAO; among them, in eyes with initial visual acuity of counting finger or worse, visual acuity improved, remained stable or deteriorated in non-arteritic CRAO in 22%, 66% and 12% respectively; in non-arteritic CRAO with cilioretinal artery sparing in 67%, 33% and none respectively; and in transient non-arteritic CRAO in 82%, 18% and none respectively. Arteritic CRAO shows no change. Recent studies have shown that administration of local intra-arterial thrombolytic agent not only has no beneficial effect but also can be harmful. Prevalent multiple misconceptions on CRAO are discussed. Branch retinal artery occlusion: Pathogeneses, clinical features and management of various types of BRAO are discussed at length. The natural history of visual acuity outcome shows a final visual acuity of 20/40 or better in 89% of permanent BRAO cases, 100% of transient BRAO and 100% of non-arteritic CLRAO alone. Cotton wools spots: These are common, non-specific acute focal retinal ischemic lesions, seen in many retinopathies. Their pathogenesis and clinical features are discussed in detail. Amaurosis fugax: Its pathogenesis, clinical features and management are described.

Efficacy of intravenous tissue-type plasminogen activator in central retinal artery occlusion: report from a randomized, controlled trial

BACKGROUND AND PURPOSE

Central retinal artery occlusion is caused by a platelet-fibrin thrombus or embolic occlusion and is a stroke of the eye. Observational studies suggest that thrombolytics may restore ocular perfusion and visual function. We hypothesized that intravenous tissue-type plasminogen activator (tPA) administered within 24 hours of symptom onset might restore ocular perfusion and visual function.

METHODS

A placebo-controlled, randomized trial of intravenous tPA versus intravenous saline was performed in patients with clinically defined central retinal artery occlusion within 24 hours of symptom onset. tPA was administered at a total dose of 0.9 mg/kg, with 10% given as a 1-minute bolus and the remainder over 1 hour. An improvement of visual acuity of 3 lines or more was considered significant.

RESULTS

Twenty-five percent (2 of 8) of the tPA group experienced the primary outcome at 1 week after tPA versus none of the placebo group. One patient had an intracranial hemorrhage. The visual acuity improvement of these 2 patients was not sustained at 6 months. In both patients, tPA was administered within 6 hours of symptom onset.

CONCLUSIONS

Although essentially a negative study, it does add to the evidence base of reperfusion in central retinal artery occlusion by showing that the time window for intervention is likely to be <6 hours. Reocclusion is a potential problem and may require adjuvant anticoagulation. Future studies should concentrate on determining the efficacy of thrombolytics in the <6-hour time window. Clinical Trial Registration- URL: http://www.anzctr.org.au. Unique identifier: 83102.

Study of the Efficacy of Intravenous Tissue Plasminogen Activator in Central Retinal Artery Occlusion

Rationale

Central retinal artery occlusion is a stroke of the eye caused by a blockage of its main blood supply by platelet-fibrin clot. Systemic thrombolysis has been successful in restoring perfusion to ischaemic tissue by fibrin-platelet clot lysis in ischaemic stroke and myocardial infarction. Several open-label studies have demonstrated efficacy of thrombolysis in the treatment of central retinal artery occlusion, with up to 60–70% of treated subjects experiencing an improvement in visual acuity. Most of these are given intraarterially, which is an invasive procedure and not widely applicable to all treatment centres. An alternative is the intravenous infusion of tissue plasminogen activator using existing stroke thrombolysis protocols. A systematic review of all observational studies of intravenous tissue plasminogen activator in acute central retinal artery occlusion showed that 48·5% of subjects had a four line or more visual acuity improvement with an acceptable rate of haemorrhagic complications, creating the equipoise necessary to conduct a randomised controlled trial.

Aim

To determine the efficacy of intravenous thrombolysis in acute treatment of central retinal artery occlusion.

Design

A phase II, placebo-controlled, double-blind, randomised controlled trial comparing intravenous tissue plasminogen activator at 0·9 mg/kg to placebo (normal saline) 100 ml in a 1 : 1 block randomisation.

Study outcome

The primary outcome measure is an improvement of three lines or more on the Snellen visual acuity chart, which signifies a doubling of the visual angle.

Intra-arterial thrombolysis for central retinal artery occlusion: two cases report

Central retinal artery occlusion (CRAO) causes severe visual loss in affected eye and vision does not recover in more than 90% of the patients. It is believed that it occurs by occlusion of the central retinal artery with small emboli from atherosclerotic plaque of internal cerebral artery. Retina is a part of the brain, thus basically CRAO is corresponding to acute occlusion of intracerebral artery and retinal ischemia is to cerebral stroke. Therefore, intra-arterial thrombolysis (IAT) has been considered as a treatment method in CRAO. Recently, we treated 2 patients diagnosed as CRAO and could achieve complete recanalization on fundus fluorescein angiogram with IAT. Of them, one recovered visual acuity to 20/25. We report our 2 CRAO cases treated with IAT and discuss technical aspects for IAT and management of patient. To the best of our knowledge, this is the first Korean report of IAT for CRAO.

Intra-arterial thrombolysis for acute central retinal artery occlusion

OBJECTIVE

In this study, we aimed at exploring the effect and safety of local intra-arterial thrombolysis on acute central retinal artery occlusion.

METHODS

Retrospective data analysis of 49 consecutive acute central retinal occlusion patients was performed. All the patients were treated with urokinase perfusion through the ophthalmology artery within the first 6 hours after central retinal artery occlusion attack. Conventional treatments including intra-ocular pressure decreasing, microcirculation improvement, neuroprotection and antiplatelet aggregation were conducted. The visual acuity (with International Snellen Chart) and field of vision were detected after thrombolysis. The complications and adverse events were observed.

RESULTS

Recanalization was found in 71% of patients. The visual acuity improvement was greater in the recanalization group (n=35) than in the non-recanalization group (n=14). The averaged visual acuity was 0.15+/-0.02, 0.25+/-0.03 and 0.4+/-0.05 after 2, 28 days and 6 months, respectively. Of the patients, 24.5% regained >0.6 of visual acuity, and the visual field deficit was less than 30% in 34.7% of patients after 28 days. Six months later, 36.7% patients regained visual acuity of >0.6, and the field deficit was less than 30% in 44.9% of patients. The difference between visual acuity in recanalization (0.6+/-0.04) and non-recanalization (0.002+/-0.0012) patients after 6 months after thrombolysis was significant (p>0.05).

CONCLUSIONS

Intra-arterial thrombolysis could obviously improve the short- and long-term visual function for patients with acute central retinal artery occlusion within 6 hours of symptom onset.

Thrombolytic therapy in central retinal artery occlusion: cutting edge therapy, standard of care therapy, or impractical therapy?

PURPOSE OF REVIEW

Numerous therapeutic options have been suggested for the treatment of central retinal artery occlusion (CRAO) such as ocular massage, anterior chamber paracentesis, physical exercise, and medication-induced reduction of intraocular pressure. Because of the lack of a proven effective treatment for CRAO, there has been a strong effort to develop alternative therapies. Recently, thrombolytic therapy has been suggested as a viable therapy for CRAO. The aim of this review is to provide an update on the progress of thrombolytic therapy for CRAO.

RECENT FINDINGS

Although there is no consensus on a standardized treatment regimen for CRAO, emerging evidence suggests that thrombolytic therapy may be effective if administered promptly. Despite the benefit of thrombolytic therapy, on the basis of the results of case reports and case series, randomized controlled studies are necessary to ultimately prove the effectiveness of the treatment.

SUMMARY

Thrombolytic therapy has yet to be validated as an effective treatment of CRAO. The execution of randomized, controlled trials is greatly needed to establish whether thrombolytic therapy can be considered standard of care therapy for CRAO.

Effects of intravitreal morphine administered at different time points after reperfusion in a rabbit model of ischemic retinopathy

PURPOSE

To investigate the effects of morphine administered after reperfusion in a rabbit model of ischemic retinopathy.

METHODS

The right eyes of 54 albino New Zealand rabbits were randomly allocated into nine treatment groups (n = 6 in each group). The eyes in saline-control group received 0.1 mL of phosphate-buffered saline solution intravitreally. In the ischemia-saline group, ischemia was induced by raising the intraocular pressure to 150 mmHg for 60 minutes. Then 0.1 mL of phosphate-buffered saline solution was administered intravitreally 5 minutes after reperfusion. The eyes in three ischemia-morphine groups (ischemia-morphine 0 hour, 1 hour, and 18 hours) received 0.1 mL of morphine (10 micromol/L) intravitreally 5 minutes, 1 hour, or 18 hours after termination of 60 minutes of ischemia, respectively. The eyes in ischemia-naloxone-morphine group received 0.05 mL of naloxone (10 micromol/L) intravitreally followed by injection of 0.05 mL morphine (10 micromol/L) 5 minutes after termination of ischemia. Toxicity controls were performed with morphine (10 micromol/L) and naloxone (10 micromol/L) without ischemia. Histologic evaluation was performed for all groups on the seventh postoperative day.

RESULTS

Sixty minutes of ischemia led to severe cell loss in ganglion cell layer and thinning of the inner nuclear layer in ischemia-saline group compared with that of the saline-control group (P < 0.001). Thickness of the inner plexiform layer to the inner limiting membrane (a measure of inner retinal thickness) was significantly increased due to edema (P < 0.001). Administration of morphine 5 minutes after reperfusion significantly improved all of the above mentioned indices compared with ischemia-saline group (P < 0.001). Administration of morphine 1 hour after reperfusion had also a significant effect on the improvement of above mentioned indices compared with saline-control group (P < 0.05). However, the number of ganglion cells was significantly higher in ischemia-morphine 0 hour group compared with ischemia-morphine 1 hour group (P < 0.001). Morphine treatment 18 hours after reperfusion did not change the amount of injury. Administration of naloxone 5 minutes before morphine abolished most of the morphine protective effects.

CONCLUSION

Intravitreal administration of morphine immediately after reperfusion maximally protects retina against ischemia-reperfusion injury. Pharmacologic evidence suggests that this protective phenomenon may be mediated in part by opioid receptors.

Interventions for acute non-arteritic central retinal artery occlusion

BACKGROUND

Acute central retinal artery occlusion (CRAO) occurs as a sudden interruption of the blood supply to the retina and results in an almost complete loss of vision in the affected eye. There is no generally agreed treatment regimen although a number of therapeutic interventions have been proposed.

OBJECTIVES

The objective of this review was to examine the effects of treatments used for acute non-arteritic CRAO.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library, Issue 3, 2008), MEDLINE (January 1966 to September 2008), EMBASE (January 1980 to September 2008) and the reference lists of relevant papers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) only in which one treatment aimed to re-establish blood supply to the retina in people with acute CRAO was compared to another treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the search results for relevant trials. Discrepancies were resolved by discussion.

MAIN RESULTS

We found two RCTs that met our inclusion criteria.

AUTHORS' CONCLUSIONS

The included studies in this review were small and from single centres. Neither study was completely clear about it's method of treatment allocation. One study described the use of pentoxifylline tablets (three 600 mg tablets daily) and the other the use of enhanced external counterpulsation (EECP) combined with haemodilution. Both studies indicated improved retinal perfusion in the non-control group but neither showed an improvement in vision. Large, well-designed RCTs are still required to establish the most effective treatment for acute CRAO. These studies should be looking at factors important to the patient i.e. improved vision with acceptable risk/side-effects.

Intravenous thrombolysis with low-dose recombinant tissue plasminogen activator in central retinal artery occlusion

PURPOSE

To evaluate the beneficial effect of intravenous thrombolysis aiming at rapid restoration of blood flow during the early hours of a central retinal artery occlusion (CRAO).

DESIGN

Interventional case series.

METHODS

In the present study, we prospectively evaluated the visual outcome after thrombolytic treatment with low-dose (50 mg) rt-PA (recombinant tissue plasminogen activator) and concomitant intravenous heparinization in patients with acute CRAO, best-corrected visual acuity (BCVA) < or = 20/100, and onset of symptoms within 12 hours prior to treatment.

RESULTS

Twenty-eight patients (28 eyes) were included in this study. Final visual acuity was improved three or more lines in nine eyes (32%), stable in 18 (64%), and worse in one eye. Time to treatment < or = 6.5 hours was associated with a better gain of lines of vision (P = .004). Seven of 17 eyes (41%) that received thrombolytic treatment within the first 6.5 hours achieved a final BCVA > or = 20/50, compared to none in the subgroup of patients with onset to treatment >6.5 hours (P = .023). We observed no serious adverse events.

CONCLUSIONS

Our findings indicate that thrombolytic treatment with intravenous low-dose rt-PA is of value for an improved visual recovery in patients with acute CRAO, if administered within the first 6.5 hours after the onset of symptoms.

Management of acute central retinal artery occlusion

Central retinal artery occlusion (CRAO) is considered to be an acute stroke of the eye that results in profound visual loss. Spontaneous recovery rates are poor. Most CRAOs are caused by thromboembolism in the central retinal artery. Current standard therapies for CRAO that aim to restore perfusion to the retina and optic nerve head have not been shown to alter the natural course of the disease. Thrombolytic therapy for acute management of CRAO has shown promise in nonrandomized studies with regard to improving visual outcomes. A randomized controlled trial will be required to confirm the efficacy of thrombolytic therapy before it can be recommended for use in CRAO in daily clinical practice.

Vitreous surgery with direct central retinal artery massage for central retinal artery occlusion

AIM

To evaluate the effectiveness of vitreous surgery with direct central retinal artery massage for the treatment of central retinal artery occlusion (CRAO).

METHODS

Vitreous surgery with direct central retinal artery massage was performed on 10 consecutive patients with acute CRAO. After standard 3 port pars plana vitrectomy, a specially designed probe was used to massage the central retinal artery on the optic nerve head or within the optic nerve or both. The best-corrected visual acuity was measured and fundus photograph was taken before operation, at 24, 48 h and weekly intervals for at least 1 month postoperatively.

RESULTS

Circulation was restored immediately during the operation in four cases, gradually since the first day after operation in four cases. There was no change in the remaining two cases, among which, central retinal vein occlusion occurred in one case 5 days later. No other complications occurred. At 2 months postoperatively, visual acuity had improved for three or more lines in six cases (60%), and remained the same in the rest of the cases.

CONCLUSIONS

Vitreous surgery with direct central retinal artery massage seems to be an effective and relatively safe treatment for CRAO

Local intraarterial fibrinolysis administered in aliquots for the treatment of central retinal artery occlusion: the Johns Hopkins Hospital experience

BACKGROUND AND PURPOSE

Central retinal artery occlusion results in acute visual loss with poor spontaneous recovery. Current standard therapies do not alter the natural history of disease. Several open-label clinical studies using continuous infusion of thrombolytic agents have suggested that local intraarterial fibrinolysis (LIF) is efficacious in the treatment of central retinal artery occlusion. The aim is to compare the visual outcome in patients with acute central retinal artery occlusion of presumed thromboembolic etiology treated with LIF administered in aliquots with that of patients treated with standard therapy.

METHODS

We conducted a single-center, nonrandomized interventional study of consecutive patients with acute central retinal artery occlusion from July 1999 to July 2006.

RESULTS

Twenty-one patients received LIF and 21 received standard therapy. Seventy-six percent of subjects in the LIF group had a visual acuity improvement of one line or more compared with 33% in the standard therapy group (P=0.012, Fisher exact). Multivariate logistic regression controlling for gender, history of prior stroke/transient ischemic attack, and history of hypercholesterolemia showed that patients who received tissue plasminogen activator were 36 times more likely to have improvement in visual acuity (P=0.0001) after adjusting for these covariates. Post hoc analysis showed that patients who received tissue plasminogen activator were 13 times more likely to have improvement in visual acuity of 3 lines or more (P=0.03) and 4.9 times more likely to have a final visual acuity of 20/200 or better (P=0.04). Two groin hematomas were documented in the LIF group. No ischemic strokes, retinal or intracerebral hemorrhages were documented.

CONCLUSIONS

LIF administered in aliquots is associated with an improvement in visual acuity compared with standard therapy and has few side effects.

Intra-Arterial Thrombolysis for Central Retinal Artery Occlusion in United States: Nationwide In-Patient Survey 2001-2003

BACKGROUND

Intra-arterial thrombolysis (IAT) has been used as a treatment modality for central retinal artery occlusion (CRAO). However, national estimates of such practice and associated outcomes are not available. We performed this study to determine the frequency and outcomes of thrombolysis among adult patients hospitalized in United States (US) for CRAO.

METHODS

We determined the rates, hospital outcomes, and hospital charges incurred for patients with CRAO treated with thrombolysis using Nationwide Inpatient Survey (NIS) and compared them with patients treated without thrombolysis. NIS is the largest all-payer inpatient care database in the US approximating a 20-percent stratified sample of US community hospitals.

RESULTS

There were 1379 admissions for primary diagnosis of CRAO in 2001-2003. IAT was used in 27(1.9%) of the patients with CRAO. There was no in-hospital mortality or intracranial hemorrhage reported among any patient with CRAO treated with thrombolysis. All patients treated with IAT were discharged home. IAT was exclusively used in urban-teaching hospitals.

CONCLUSIONS

There is potential of benefit from IAT in CRAO, which is only offered in certain centers. Clinical trials are needed to demonstrate this beneficial effect.

Thrombolysis for Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) frequently causes severe and irreversible visual loss. For many years, various conservative treatments have been proposed for acute CRAO, but their efficacy remains unproven. Over the past 20 years, CRAO has also been treated with thrombolytic agents administered intravenously or intra-arterially. However, all thrombolytic studies are retrospective and uncontrolled, so that the benefit of this treatment remains uncertain. A prospective controlled clinical trial is ongoing in Europe and should provide more reliable information. Even if this trial demonstrates a benefit, thrombolytic treatment is unlikely to become widespread in the management of CRAO unless it can be deployed quickly after the event.

Cardiovascular and thrombophilic risk factors in patients with retinal artery occlusion

This article evaluates the prevalence of cardiovascular and thrombophilic risk factors in patients with retinal artery occlusion. Forty-one patients with a first episode of a retinal artery occlusion underwent complete ophthalmic examination, routine blood testing and specific laboratory tests for thrombophilia, such as fasting and postmethionine homocysteine, lipoprotein(a), plasminogen activator inhibitor-1, factor VIII, factor V Leiden, factor II G20210A polymorphism, lupus anticoagulant and anticardiolipin antibodies. The control population consisted of 100 healthy individuals comparable as regards age and sex. At univariate analysis, hypertension, smoking, dyslipidaemia (both high cholesterol and triglyceride levels), antiphospholipid antibodies, hyperhomocysteinaemia, elevated factor VIII and lipoprotein(a) levels were significantly associated with retinal artery occlusion; at multivariate analysis, adjusted for age, sex, traditional and thrombophilic risk factors, smoking, hypercholesterolaemia, elevated homocysteine and lipoprotein(a) levels confirmed their independent role as risk factors for retinal artery occlusion. In conclusion, the results of the present pilot study demonstrate that the prevalence of hypercholesterolaemia and smoking and the 'thrombophilic burden' are increased in patients with retinal artery occlusion. Our findings may have implications for the management of these patients, suggesting the need for an intensive and tailored secondary prevention and new therapeutic approaches.

Lysetherapie vs. konservative Therapie

In the prospective, randomised and multicenter EAGLE study, the therapeutic efficiency of local intra-arterial fibrinolysis (LIF) versus conservative treatment is being tested in patients with an acute central retinal artery occlusion (CRAO). The most important inclusion criteria are: (1) age between 18-75 years, (2) CRAO not older than 20 h, and (3) visual acuity <0.32. The primary study endpoint is the visual acuity before and 1 month after therapy. The study was started in 2002. To August 2006, 63 of the 200 required patients have been included in the study at 17 medical centers in Germany, Switzerland and Austria.

Surgical embolus removal in retinal artery occlusion

AIMS

To evaluate the anatomical outcomes, safety and functional effectiveness of surgical embolus removal in retinal artery occlusion (RAO).

METHODS

Prospective study of seven patients with RAO of <36 h duration. All eyes underwent pars plana vitrectomy and a longitudinal incision of the anterior wall of the occluded arteriole in an attempt to remove the embolus. Outcome measures included visual acuity and arteriolar reperfusion, as evaluated with fluorescein angiography.

RESULTS

Surgical removal of the embolus was achieved in six of the seven (87.5%) patients, visual acuity improved from a median of 20/400 (range: hand movements 20/25) to 20/40 (range: hand movements 20/25), and reperfusion of the occluded vessel was angiographically confirmed in four of the six patients in whom the embolus was successfully removed.

CONCLUSION

Surgical removal of retinal arterial emboli seems to be an effective and safe treatment for RAO, but a randomised and controlled clinical trial will be necessary to establish an evidence base for the role, if any, of this intervention.