[Occlusion of the retinal artery]

[Nonaretritic central retinal artery occlusion as marker for the generalized vascular risk]

BACKGROUND

Retinal artery occlusion (RAO) represents a limiting visual perception for affected patients. In all efforts to improve function it must not be forgotten that in the vast majority of cases the cause is one or more severe vascular or cardiac diseases, which can cause RAO just as ischemic stroke and can also be life-threatening.

OBJECTIVE

The aim of this article is to present the available literature and to explain the importance of an intensive neurological internal medical clarification in RAO patients.

CONCLUSION

Although cardiovascular diseases are already known in most patients at the onset of an RAO, further risk factors are detected in almost 80% of cases. Therefore, and because of the high risk for recurrent thromboembolism, immediate and standardized neurological internal medical clarification of the cause is urgently recommended after an acute RAO in the context of an inpatient stay.

iNOS-inhibitor driven neuroprotection in a porcine retina organ culture model

Nitrite oxide plays an important role in the pathogenesis of various retinal diseases, especially when hypoxic processes are involved. This degeneration can be simulated by incubating porcine retinal explants with CoCl₂. Here, the therapeutic potential of iNOS‐inhibitor 1400W was evaluated. Degeneration through CoCl₂ and treatment with the 1400W were applied simultaneously to porcine retinae explants. Three groups were compared: control, CoCl₂, and CoCl₂ + iNOS‐inhibitor (1400W). At days 4 and 8, retinal ganglion cells (RGCs), bipolar, and amacrine cells were analysed. Furthermore, the influence on the glia cells and different stress markers were evaluated. Treatment with CoCl₂ resulted in a significant loss of RGCs already after 4 days, which was counteracted by the iNOS‐inhibitor. Expression of HIF‐1α and its downstream targets confirmed the effective treatment with 1400W. After 8 days, the CoCl₂ group displayed a significant loss in amacrine cells and also a drastic reduction in bipolar cells was observed, which was prevented by 1400W. The decrease in microglia could not be prevented by the inhibitor. CoCl₂ induces strong degeneration in porcine retinae by mimicking hypoxia, damaging certain retinal cell types. Treatment with the iNOS‐inhibitor counteracted these effects to some extent, by preventing loss of retinal ganglion and bipolar cells. Hence, this inhibitor seems to be a very promising treatment for retinal diseases.

[Retinal artery occlusion]

Retinal artery occlusion leads to profound visual impairment in the affected eye. It is rarely caused by local ophthalmic pathologies. Most patients present with a large number of cardio- and cerebrovascular risk factors. Visual loss is the leading symptom in central retinal artery occlusion (CRAO), whereas a circumscribed visual field defect is claimed in branch retinal artery occlusion (BRAO). Although many attempts have been made to improve the course of the disease, no effective therapy is available. There is some hope that intravenous fibrinolysis could influence the natural course but the therapeutic window is small (ca. 4.5 h), and treatment efficacy is still not proven. It is important for ophthalmologists to guide the patients to a comprehensive and prompt neurological and cardiological diagnostic work-up.

Selective Thrombophilia Screening in Young Patients with Retinal Artery Occlusion

Purpose: To investigate the prevalence of various thrombophilic disorders among young patients with retinal artery occlusion (RAO). Procedures: We retrospectively reviewed thrombophilia screening data of young patients ≤60 years of age with RAO and healthy controls matched for gender and age. Results: Thrombophilia screening data of 25 young patients and 62 healthy controls were analyzed. Mean patient age by the time of the RAO was 43.3 ± 10.8 years. Overall, thrombophilic defects were found to be present in 17 patients (68%) compared with 11 of 62 controls (17.7%; p < 0.0001). Multivariate logistic regression analysis confirmed a statistically significant association between the development of RAO and increased levels of lipoprotein(a) (odds ratio: 9.48; p = 0.001) and factor VIII (odds ratio: 6.41; p = 0.024). There was a strong association between the presence of thrombophilic disorders and a personal or family history of thromboembolism (p = 0.01). Conclusions: Our results indicate that screening for thrombophilic disorders among selected young patients with RAO yields positive results in a high percentage of cases.

Retinal vascular occlusions: an interdisciplinary challenge

INTRODUCTION

Retinal venous and arterial occlusions are common causes of visual loss. Depending on the location and extent, symptoms may vary from very discrete impairments to complete loss of sight.

METHODS

Selective literature review including the authors' own research data with a particular focus on interdisciplinary aspects.

RESULTS

Retinal vascular occlusions are not a uniform entity. Rather, they reflect the whole breadth of vascular disease. In arterial occlusion, embolic phenomena and Horton's arteritis should be excluded, in addition to local ophthalmological investigations. In retinal venous occlusion, optimal treatment of arterial hypertension is universally useful, while investigations for thrombophilia are useful in patients under 50 years of age. The results of intravitreal injection of corticosteroids and vascular endothelial growth factor inhibitors appear encouraging in treatment of macular edema secondary to retinal vein occlusion.

DISCUSSION

While local diagnostic and therapeutic measures are performed by ophthalmologists, there is an important role for interdisciplinary cooperation in the investigation and systemic treatment of these events.

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.

Multicenter study of the European Assessment Group for Lysis in the Eye (EAGLE) for the treatment of central retinal artery occlusion: design issues and implications. EAGLE Study report no. 1 : EAGLE Study report no. 1

BACKGROUND

The natural course of central retinal artery occlusion (CRAO) often leads to legal blindness in the affected eye. To date, none of the conservative therapies had proven effective in retrospective studies. In 1991, a new minimally invasive therapy was started in patients with an acute CRAO. This therapy, namely, local intra-arterial fibrinolysis, is comparable to the minimally invasive therapy in patients with an acute ischemic stroke. In pilot studies, it showed promising results in comparison with conservative treatments. The efficacy of this method is now being investigated in a randomized multicenter study.

METHODS

The European Assessment Group for Lysis in the Eye (EAGLE) started a prospective and randomized multicenter study in 2002 to evaluate therapeutic efficacy. Inclusion criteria are age between 18 and 75 years and a CRAO not older than 20 h with a visual acuity less than 0.32. The most important exclusion criteria are branch retinal artery occlusion (BRAO), cilioretinal arteries supplying the macula, and serious general disease. After randomization the patient is treated by conservative or local intra-arterial lysis therapy. The conservative regime included bulbus massage, lowering intraocular pressure with topical beta-blocker and acetazolamide, acetylsalicylic acid, heparin, and-depending on the hematocrit-isovolemic hemodilution. In case of local intra-arterial fibrinolysis, a maximum of 50 mg rtPA is injected into the ophthalmic artery by the neuroradiologist. During the following 5 days, all patients are treated with heparin. Primary study end point is visual acuity 1 month after therapy in comparison with visual acuity before therapy. The calculated sample size is 100 patients per subtrial (a total of 200 patients). The study was started in June 2002. To April 2005, 47 patients were included.

CONCLUSIONS

The EAGLE Study is the first randomized prospective clinical trial to compare conservative medical treatment and local intra-arterial fibrinolysis in patients with CRAO. The results of this study should enable ophthalmologists and neuroradiologists to improve the therapy of patients with acute CRAO. To April 2005, treatment is only justified in randomized multicenter studies because of the limited therapeutical visual outcome. We welcome new study centers to join.

Klassifikation biomedizinischer Forschungsberichte als Grundlage evidenzbasierter Medizin in der Augenheilkunde

BACKGROUND

Evidence-based medicine requires careful appraisal of published data derived from experimental and clinical studies. Based on classification of biomedical research reports, evidence levels can be determined and recommendations for therapeutic decisions can be made.

METHODS

A classification system for clinical studies was developed. It was evaluated in classifying the reports published in Der Ophthalmologe during 2003-2004 (study design: descriptive cross-sectional study, case series).

RESULTS

In the 2-year interval, 70 longitudinal and 95 cross-sectional studies were published. The vast majority of the longitudinal studies were interventional cohort studies. Not considering case reports, 73% of the original articles were longitudinal prospective studies, 1% were retrospective (case-control) studies, and 26% were cross-sectional studies.

CONCLUSIONS

The study design of all published articles could be classified using the classification system. This classification system proves to be applicable in the context of clinical studies in ophthalmology and may be helpful in the process of critical appraisal of the literature and synthesis of clinical evidence and an evidence-based recommendation.