Indocyanine green versus fluorescein angiography in the differential diagnosis of arteritic and nonarteritic anterior ischemic optic neuropathy

Color Doppler Eye Ultrasonography in giant cell arteritis: differential diagnosis between arteritic and non-arteritic sudden blindness

PURPOSE

Temporal (TA) and axillary (AXA) arteries Color Doppler Ultrasonography (CDUS) is the most reliable diagnostic technique for the diagnosis of giant cell arteritis (GCA), displaying high sensitivity and specificity. Nevertheless, CDUS is still poorly performed in the common clinical practice, being employed only by rheumatologists with a relevant expertise in this field. Color Doppler Eye Ultrasound (CDEUS) is a procedure variously employed in ophthalmology and preliminary findings have displayed a possible role also in the diagnostic work-up of GCA. Aim of this study was to assess whether CDEUS may play a role in the differential diagnosis between arteritic and non-arteritic blindness.

METHODS

We prospectively included all patients evaluated since September 2021 to May 2022 by our Ophthalmology Unit for sudden blindness and referred to our Vasculitis Clinic in the suspicion of GCA. All patients underwent complete ophthalmological evaluation, routine blood tests, AxA and TA CDUS and CDEUS. According to the definite diagnosis, patients were divided in the following subgroups: (A) patients suffering from arteritic central retinal artery occlusion (CRAO), (B) patients suffering from non-arteritic CRAO, (C) patients suffering from arteritic anterior ischemic optic neuropathy (AION), (D) patients suffering from non-arteritic AION.

RESULTS

During the observational period, we included a total of 25 patients suffering from sudden blindness and referred to Vasculitis Clinic for ruling out GCA. Patients belonging to group A showed no flow or reduced flow within the territory of central retinal artery (CRA), no "spot sign" and positive TA CDUS; on the other hand, patients from group B presented normal TA CDUS, no flow or reduced flow within the territory of CRA and the presence of "spot sign". Conversely, no relevant difference was evidenced at CDEUS in patients with and without arteritic AION.

CONCLUSION

Our preliminary data displayed a good reliability of CDEUS in distinguishing between arteritic and non-arteritic CRAO, while no difference was assessed between arteritic and non-arteritic AION. Since AION represents the most common presentation of cranial GCA, CDEUS does not seem a reliable procedure in the diagnostic work-up of GCA and should be restricted only to the exclusion of thrombo-embolic occlusions within the territory of central retinal artery.

Vascular supply of the optic nerve head: implications for optic disc ischaemia

The vascular supply of the optic nerve head is complex and remains incompletely delineated. Over the past 50 years, various investigators have attempted to clarify the relative contributions of the choroid, the short posterior ciliary arteries and the central retinal artery to the vascular beds of the inner retinal, prelaminar, laminar and retrolaminar segments of the nerve head. Conflicting theories have evolved, in no small part due to differing techniques of study, involving both flow parameters and anatomical constructs. These have included studies, both in normal subjects and in those with optic nerve ischaemia, of histopathology, electron microscopic corrosion casting, orbital colour Doppler flow studies, fluorescein angiography, indocyanine green angiography, laser Doppler flow studies, laser speckle flowgraphy, microperfusion and labelling studies and optical coherence tomography angiography. The nature of the optic disc, peripapillary retina and choroid microvasculature has implications for the pathophysiology of ischaemic optic neuropathy.

[Unusual forms of inflammatory diseases of the central nervous system]

BACKGROUND

White matter lesions of the central nervous system (CNS) are frequently encountered on magnetic resonance imaging (MRI) exams. If the morphologic findings, clinical symptoms and laboratory results are not typical for one of the more common inflammatory CNS diseases, the diagnosis may become challenging, which also means that interesting and sometime emotional discussions may arise.

OBJECTIVE

While frequent causes of inflammatory CNS diseases were already discussed in a previous article, we now focus on more seldom forms and place attention on morphologic characteristics which may help to find the correct diagnosis.

Ischemic Choroidal Diseases

INTRODUCTION

Ischemic choroidal diseases are an underdiagnosed entity. The clinical pattern varies according to the size and the localisation of the affected vascular structure.

CLINICAL PRESENTATION

In eyes with occlusion of the long posterior ciliary arteries, characteristic triangular patches of choroidal ischemia (Amalric sign) are seen, which in the course of time merge into well-defined areas of atrophy of the retinal pigment epithelium. Above the non-perfused choroidal areas, hyperpigmented, grouped lines appear (Siegrist streaks). Circumscribed ischemia of smaller choroidal arterioles and capillary vessels appears as multifocal, yellowish lesions in the posterior fundus (Elschnig spots). Vortex vein occlusion becomes manifest as exudative haemorrhagic choroidal swelling in the periphery.

CAUSES OF CHOROIDAL ISCHEMIA

Apart from arterial hypertension as a major risk factor, some immunological disorders such as giant cell arteritis and systemic lupus erythematosus and haematological pathologies also affect choroidal perfusion. Furthermore, choroidal ischemia occurs due to local inflammation, as found in eyes with acute multifocal posterior placoid pigment epitheliopathy (APMPPE). Rarely, choroidal infarction is of iatrogenic origin or drug-induced. Recent advances in imaging, such as the introduction of enhanced depth imaging optical coherence tomography (EDI-OCT) and OCT angiography (OCT-A), have improved the visualisation of the choroidal vasculature and complement the classical angiographic procedures. In patients with age-related macular degeneration (AMD) and diabetes, some changes in choroidal blood flow and vascular structure have also been noted. While in AMD the choroidal pathologies correlate with the disease progression and the functional prognosis, the pathophysiological relationship between diabetic choroidopathy and retinopathy is currently unclear.

MANAGEMENT AND CONCLUSION

With regard to the limited therapeutic options for choroidal ischemia, optimisation of the cardiovascular risk profile and the management of accompanying ocular and systemic diseases are essential.

Simultaneous Bilateral Primary Occlusion of the Ophthalmic Artery due to Florid Giant Cell Arteritis

PURPOSE

To report a case of simultaneous bilateral ophthalmic artery occlusion in diagnosed giant cell arteritis (GCA).

OBSERVATIONS

A 77-year-old male patient presented to the emergency department with simultaneous vision loss in both eyes for 3 hours. Headache at both temples and jaw claudication had been present for 3 weeks. Laboratory values demonstrated an initially increased C-reactive protein (CRP) of 202.0 mg/L and an erythrocyte sedimentation rate (ESR) of 100 mm within the first 20 minutes. Duplex sonography of the right and left temporal arteries revealed a "halo sign." A case of GCA was suspected, and intravenous high-dose methylprednisolone therapy was immediately administered. The clinical examination revealed a bilateral central retinal artery occlusion and fluorescein angiography showed a hot optic disc in the right eye and patchy choroidal hypoperfusion in both eyes. Biopsy of the left temporal artery was performed, which confirmed a florid temporal arteritis with complete thrombotic occlusion of the vascular lumen. Despite a good response to the administered therapy (CRP 17.0 mg/L 1 week after initiation), the visual prognosis was significantly limited through retinal and optic nerve involvement. By the follow-up examination 8 weeks later, the near visual acuity was 20/400 in the right and left eye at a distance of 16 inches.

CONCLUSION AND IMPORTANCE

We hereby present a simultaneous bilateral ophthalmic artery occlusion as a rare complication of GCA. The combination of central retinal artery occlusion, arteritic anterior ischemic optic neuropathy, and choroidal hypoperfusion suggests an acute inflammatory involvement of the ophthalmic artery. In cases of the slightest suspicion of giant cell arteritis, an immediate high-dose steroid therapy initiation is of utmost importance.

Diagnosis and management of giant cell arteritis: Major review

Giant cell arteritis is a medical emergency because of the high risk of irreversible blindness and cerebrovascular accidents. While elevated inflammatory markers, temporal artery biopsy and modern imaging modalities are useful diagnostic aids, thorough history taking and clinical acumen still remain key elements in establishing a timely diagnosis. Glucocorticoids are the cornerstone of treatment but are associated with high relapse rates and side effects. Targeted biologic agents may open up new treatment approaches in the future.

[Acute ischemic optic nerve disease: Pathophysiology, clinical features and management (French translation of the article)]

Ischemic optic neuropathies are among the leading causes of severe visual acuity loss in people over 50 years of age. They constitute a set of various entities that are clinically, etiologically and therapeutically different. Anatomically, it is necessary to distinguish anterior and posterior forms. From an etiological point of view, the diagnosis of the arteritic form due to giant cell arteritis requires emergent management to prevent blindness and even death in the absence of prompt corticosteroid treatment. When this diagnosis has been ruled out with certainty, non-arteritic ischemic optic neuropathies represent a vast etiological context that in the majority of cases involves a local predisposing factor (small optic nerves, disc drusen) with a precipitating factor (severe hypotension, general anesthesia or dialysis) in a context of vascular disease (sleep apnea syndrome, hypertension, diabetes, etc.). In the absence of specific available treatment, it is the responsibility of the clinician to identify the risk factors involved, in order to reduce the risk of contralateral recurrence that may occur even several years later. Due to their complexity, these pathologies are the subject of debates regarding both the pathophysiological and therapeutic perspectives; this review aims to provide a synthesis of validated knowledge while discussing controversial data.

Acute ischemic optic nerve disease: Pathophysiology, clinical features and management

Ischemic optic neuropathies are among the leading causes of severe visual acuity loss in people over 50 years of age. They constitute a set of various entities that are clinically, etiologically and therapeutically different. Anatomically, it is necessary to distinguish anterior and posterior forms. From an etiological point of view, the diagnosis of the arteritic form due to giant cell arteritis requires emergent management to prevent blindness and even death in the absence of prompt corticosteroid treatment. When this diagnosis has been ruled out with certainty, non-arteritic ischemic optic neuropathies represent a vast etiological context that in the majority of cases involves a local predisposing factor (small optic nerves, disc drusen) with a precipitating factor (severe hypotension, general anesthesia or dialysis) in a context of vascular disease (sleep apnea syndrome, hypertension, diabetes, etc.). In the absence of specific available treatment, it is the responsibility of the clinician to identify the risk factors involved, in order to reduce the risk of contralateral recurrence that may occur even several years later. Due to their complexity, these pathologies are the subject of debates regarding both the pathophysiological and therapeutic perspectives; this review aims to provide a synthesis of validated knowledge while discussing controversial data.

Exploring choroidal angioarchitecture in health and disease using choroidal vascularity index

The choroid is one of the most vascularized structures of the human body and plays an irreplaceable role in nourishing photoreceptors. As such, choroidal dysfunction is implicated in a multitude of ocular diseases. Studying the choroid can lead to a better understanding of disease pathogenesis, progression and discovery of novel management strategies. However, current research has produced inconsistent findings, partly due to the physical inaccessibility of the choroid and the lack of reliable biomarkers. With the advancements in optical coherence tomography technology, our group has developed a novel quantitative imaging biomarker known as the choroidal vascularity index (CVI), defined as the ratio of vascular area to the total choroidal area. CVI is a potential tool in establishing early diagnoses, monitoring disease progression and prognosticating patients. CVI has been reported in existing literature as a robust marker in numerous retinal and choroidal diseases. In this review, we will discuss the current role of CVI with reference to existing literature, and make postulations about its potential and future applications.

Choroidal Vascular Changes in Arteritic and Nonarteritic Anterior Ischemic Optic Neuropathy

PURPOSE

To compare choroidal vascularity index (CVI) in patients with arteritic anterior ischemic optic neuropathy (A-AION), nonarteritic anterior ischemic optic neuropathy (NA-AION), and control subjects.

DESIGN

Retrospective cross-sectional study.

METHODS

This study was conducted at the Ophthalmology Unit of the S.Orsola-Malpighi University Hospital (Bologna, Italy). Macular and optic nerve head optical coherence tomography (OCT) scans of 20 patients with A-AION secondary to giant cell arteritis (biopsy-proven), 20 patients with NA-AION, and 20 control subjects were acquired with Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany). Images were binarized using ImageJ software, and total choroid area (TCA), luminal area (LA), and stromal area (SA) were segmented. The main outcome measure was CVI, defined as the ratio of LA to TCA.

RESULTS

Patients with A-AION showed a significantly lower macular and peripapillary CVI compared to both patients with NA-AION (respectively, 67.17 ± 2.35 vs 69.66 ± 4.18, P = .048; 63.51 ± 3.29 vs 67.67 ± 3.07, P < .001) and control subjects (respectively, 67.17 ± 2.35 vs 70.00 ± 2.95, P = .021; 63.51 ± 3.29 vs 68.69 ± 3.19, P = .002). Conversely, no significant difference in macular and peripapillary CVI was found between patients with NA-AION and controls (respectively, P = .942 and P = .570). After adjustment for age, the difference of peripapillary CVI among groups remained statistically significant (P < .001), while the difference in macular CVI did not (P = .060).

CONCLUSIONS

Macular and peripapillary CVI are reduced in patients with A-AION. These parameters may be useful to quantitatively evaluate choroidal vascular dysfunction in A-AION, serving as a new additional diagnostic tool to distinguish A-AION from NA-AION.

Optical coherence tomography angiography in acute arteritic and non-arteritic anterior ischemic optic neuropathy

PURPOSE

The purpose of our study was to describe the feature of acute non-arteritic or arteritic anterior ischemic optic neuropathy (NA-AION and A-AION) using optical coherence tomography angiography (OCT-A) and to compare it with fluorescein angiography (FA) and indocyanine green angiography (ICGA).

METHODS

In this retrospective, observational case-control study four NA-AION patients and one A-AION patient were examined by FA, ICGA and OCT-A within 2 weeks from disease presentation. The characteristics of the images were analyzed. Optic nerve head (ONH) and radial peripapillary capillaries (RPC) vessel densities (VDs) were compared between NA-AION and controls.

RESULTS

In two of four NA-AION cases and in the A-AION patient, OCT-A clearly identified the boundary of the ischemic area at the level of the optic nerve head, which was comparable to optic disc filling defects detected by FA. In the other two NA-AION cases, a generalized leakage from the disc was visible with FA, yet OCT-A still demonstrated sectorial peripapillary capillary network reduction. Both ONH and RPC VDs were reduced in NA-AION patients, when compared to controls.

CONCLUSIONS

OCT-A was able to identify microvascular defects and VD reduction in cases of acute optic disc edema due to NA-AION and A-AION. OCT-A provides additional information in ischemic conditions of the optic nerve head.

Evaluation of Choroidal Thickness in Non-arteritic Anterior Ischaemic Optic Neuropathy at the Acute and Chronic Stages

The objective of this study was to evaluate the measurements of choroidal thickness (CT) in patients with non-arteritic anterior ischaemic optic neuropathy (NAION) at the acute and chronic stages. This case-control study compares three groups: Group 1 included 23 eyes of 23 patients with chronic NAION, Group 2 consisted of 24 eyes of 24 patients with acute NAION, and Group 3 included 24 eyes of 24 age-matched control subjects. The average CTs for Group 1, Group 2, and Group 3 were 261.24 ± 50.04, 280.05 ± 74.94, and 254.74 ± 50.11 µm, respectively. For all measurements, no statistical significance was found between the groups (p = 0.319, 0.357, 0.680, and 0.178 for the CTs as average, foveal, superior, and inferior, respectively). Similarly, there was no difference between the CT measurements of the affected and unaffected eyes in Group 1 and Group 2 (p = 0.571, 0.741 for average, respectively). The amount of time after the onset of the disease ranged from 6.0 to 48 months (23.86 ± 16.70 months) in Group 1 and from 1 to 30 days (7.45 ± 8.86 days) in Group 2. There was no correlation between the CTs and follow-up times in Group 1 (p = 0.768 for average) and no association between the CTs and the thicknesses of the retinal nerve fibre layers in Group 2 (p = 0.453 for average). CT is not directly influenced by NAION at either the acute or the chronic stage of the disease. These results may also demonstrate that the changes of CT do not increase the risk of experiencing a NAION attack.

Acute vision loss and choroidal filling delay in the absence of giant-cell arteritis

Giant-cell arteritis (GCA) is a visually devastating disease that often progresses to severe bilateral vision loss if untreated. Diagnosis of GCA is made challenging by the protean nature of the disease and the lack of a simple test that is both highly sensitive and specific. Choroidal filling delay on fluorescein angiography (FA) has been touted as a highly characteristic feature of GCA-related vision loss, although knowledge of both the sensitivity and specificity of this finding remains unproven. We report our experience of delayed choroidal filling on FA in a series of seven patients referred to an academic neuro-ophthalmology practice due to concern for GCA. Despite the FA findings, our examination, diagnostic testing, and long-term follow-up excluded the diagnosis of GCA in all cases, suggesting that choroidal perfusion abnormalities may occur in the absence of GCA. When evaluating a patient for acute vision loss, the astute clinician must remain cognizant of the limitations of FA in the diagnosis of GCA.

New developments in giant cell arteritis

Giant cell arteritis (GCA) is a medium-to-large vessel vasculitis with potentially sight- and life- threatening complications. Our understanding of the pathogenesis, diagnosis, and treatment of GCA has advanced rapidly in recent times. The validity of using the American College of Rheumatology guidelines for diagnosis of GCA in a clinical setting has been robustly challenged. Erythrocyte sedimentation rate, an important marker of inflammation, is lowered by the use of statins and nonsteroidal anti-inflammatory drugs. Conversely, it may be falsely elevated with a low hematocrit. Despite the emergence of new diagnostic modalities, temporal artery biopsy remains the gold standard. Evidence suggests that shorter biopsy lengths and biopsies done weeks to months after initiation of steroid therapy are still useful. New imaging techniques such as positron emission tomography have shown that vascular inflammation in GCA is more widespread than originally thought. GCA, Takayasu arteritis, and polymyalgia rheumatica are no longer thought to exist as distinct entities and are more likely parts of a spectrum of disease. A range of immunosuppressive drugs have been used in conjunction with corticosteroids to treat GCA. In particular, interleukin-6 inhibitors are showing promise as a therapy.

Ischemic optic neuropathies and their models: disease comparisons, model strengths and weaknesses

Ischemic optic neuropathies (IONs) describe a group of diseases that specifically target the optic nerve and result in sudden vision loss. These include nonarteritic and arteritic anterior ischemic optic neuropathy (NAION and AAION) and posterior ischemic optic neuropathy (NPION, APION). Until recently, little was known of the mechanisms involved in ION damage, due to a lack of information about the mechanisms associated with these diseases. This review discusses the new models that closely mimic these diseases (rodent NAION, primate NAION, rodent PION). These models have enabled closer dissection of the mechanisms involved with the pathophysiology of these disorders and enable identification of relevant mechanisms and potential pathways for effective therapeutic intervention. Descriptions of the different models are included, and comparisons between the models, their relative similarities with the clinical disease, as well as differences are discussed.

The primary vascular dysregulation syndrome: implications for eye diseases

Vascular dysregulation refers to the regulation of blood flow that is not adapted to the needs of the respective tissue. We distinguish primary vascular dysregulation (PVD, formerly called vasospastic syndrome) and secondary vascular dysregulation (SVD). Subjects with PVD tend to have cold extremities, low blood pressure, reduced feeling of thirst, altered drug sensitivity, increased pain sensitivity, prolonged sleep onset time, altered gene expression in the lymphocytes, signs of oxidative stress, slightly increased endothelin-1 plasma level, low body mass index and often diffuse and fluctuating visual field defects. Coldness, emotional or mechanical stress and starving can provoke symptoms. Virtually all organs, particularly the eye, can be involved. In subjects with PVD, retinal vessels are stiffer and more irregular, and both neurovascular coupling and autoregulation capacity are reduced while retinal venous pressure is often increased. Subjects with PVD have increased risk for normal-tension glaucoma, optic nerve compartment syndrome, central serous choroidopathy, Susac syndrome, retinal artery and vein occlusions and anterior ischaemic neuropathy without atherosclerosis. Further characteristics are their weaker blood–brain and blood-retinal barriers and the higher prevalence of optic disc haemorrhages and activated astrocytes. Subjects with PVD tend to suffer more often from tinnitus, muscle cramps, migraine with aura and silent myocardial ischaemic and are at greater risk for altitude sickness. While the main cause of vascular dysregulation is vascular endotheliopathy, dysfunction of the autonomic nervous system is also involved. In contrast, SVD occurs in the context of other diseases such as multiple sclerosis, retrobulbar neuritis, rheumatoid arthritis, fibromyalgia and giant cell arteritis. Taking into consideration the high prevalence of PVD in the population and potentially linked pathologies, in the current article, the authors provide recommendations on how to effectively promote the field in order to create innovative diagnostic tools to predict the pathology and develop more efficient treatment approaches tailored to the person.

Giant cell arteritis: a review

Giant cell arteritis is the most common vasculitis in Caucasians. Acute visual loss in one or both eyes is by far the most feared and irreversible complication of giant cell arteritis. This article reviews recent guidelines on early recognition of systemic, cranial, and ophthalmic manifestations, and current management and diagnostic strategies and advances in imaging. We share our experience of the fast track pathway and imaging in associated disorders, such as large-vessel vasculitis.

Susac's syndrome: an update

Susac's syndrome is an infrequent neurological disorder characterized by the clinical triad of encephalopathy, hearing loss, and branch retinal artery occlusions. Its pathophysiology is not entirely clear, although it is now thought that it is most probably an immune-mediated endotheliopathy that affects the microvasculature of the brain, retina, and inner ear. An early diagnosis is important as treatment can halt disease progression and prevent permanent disability.

Krogh cylinders in retinal development, panretinal hypoperfusion and diabetic retinopathy

The volume of cells that a length of capillary supplies with O(2) is called a Krogh cylinder. This geometric 'tissue unit' was named after the Danish zoophysiologist and Nobel laureate August Krogh who made important discoveries in the fields of external and internal respiration in the first half of the last century. Krogh's ideas concerning tissue O(2) distribution can be extrapolated to retinal oxygenation by larger vessels (including arterioles, arteries and even veins) and by vessel groups within higher-order 'microvascular units' (including the choroid). During retinal development, for example, the difference in pO(2) levels within arteries and capillaries determines Krogh cylinders of different radius and establishes the periarterial capillary-free zone of His. The O(2) supply to the venous end of a tissue unit may be compromised during periods of reduced perfusion, increased O(2) consumption or hypoxaemia, resulting in an 'anoxic corner' of the Krogh cylinder. A funnel of hypometabolic (and therefore hypoxia-tolerant) cells will likely intervene between the necrotic cells and unaffected cells located closer to the O(2) source. Macular perivenular whitening heralds anoxic corners and/or hypoxic funnels owing to hypoperfusion within second-order microvascular units. In eyes with extensive retinal capillary closure from diabetes, Krogh cylinders surround the medium-sized arteries and veins that form arteriovenous shunts while traversing the midperipheral retina. These isolated tissue units incorporate an outer sheath of hypoxic cells within which vascular endothelial growth factor is upregulated. This 'angiogenic sheath' expands following retinal detachment; it corresponds to the hypoxia-tolerant funnel within capillary-based tissue units and to the cerebral penumbra after stroke.

Bietti's crystalline dystrophy in Asians: clinical, angiographic and electrophysiological characteristics

This article describes nine Chinese patients with Bietti's crystalline dystrophy, including two families, one consisting of three siblings and the other a pair of sisters. All patients had the classic refractile deposits located in all layers of the retina, with varying degrees of pigment epithelium atrophy. However, paralimbal crystals were not seen in the anterior corneal stroma. We describe clinical, angiographical and electrophysiological characteristics, and also review the literature on Bietti's crystalline dystrophy. All patients had full eye examination, including best corrected visual acuity, biomicroscopy, applanation tonometry and dilated funduscopy. Fluorescein angiography and indocyanine green angiography were performed, together with visual fields and electrophysiologic studies. All nine of our patients were phenotypically heterogeneous, with varying age and symptoms at presentation, as well as different degrees of progression. Age was not found to be a predictor of severity. The differences in disease severity, even within sibling groups, suggested that perhaps other factors were at play in phenotypic expression. We found that in early ICGA, all stages of BCD had delayed choroidal filling, which has not been previously described. We also observed a relative derangement of inner choroidal circulation as evidenced by late hypofluorescence on the ICGA. However, it is as yet unclear whether this circulatory disturbance is due to primary involvement of the posterior ciliary arteries, or secondary to choroidal and/or retinal pigment epithelial atrophy. While the FA and ICGA findings were similar, we found that the true extent of the atrophic areas was better delineated by ICGA. ICGA was also superior in outlining the degree and extent of choroidal vascular compromise.

Fluorescein and indocyanine green angiographies in Susac syndrome

PURPOSE

Susac syndrome is a rare microangiopathy of the brain, retina, and cochlea that mainly affects young women. We studied the management of this disease using retinal fluorescein and indocyanine green angiographies.

METHODS

Retrospective, observational case series of seven patients with Susac syndrome identified in ophthalmology and internal medicine departments. We reviewed medical, ophthalmologic, and angiographic records at study enrollment and during long-term treatment. Mean follow-up was 37 months. Best-corrected visual acuity, intraocular inflammation score, ophthalmoscopy data, automated perimetry score, and fluorescein and indocyanine green angiographic features were analyzed with the results of cerebral magnetic resonance imaging and spinal fluid analysis and ENT signs.

RESULTS

Retinal fluorescein angiography showed focal nonperfused retinal arterioles with hyperfluorescent walls in all cases. Indocyanine green angiography showed normal choroidal circulation. Retinal vasculitis was uncontrolled in a patient treated with steroids. Improvement of retinal arteriole perfusion occurred during immunosuppressive treatment with cyclophosphamide.

CONCLUSION

Absence of intraocular inflammation and focal, labile nonperfused retinal arterioles with integrity of choroidal circulation are monomorphic ophthalmologic features that could immediately suggest the diagnosis of Susac syndrome. Early ophthalmologic examination aided by retinal fluorescein angiography could be useful for managing cases of unexplained neurologic symptoms in women.

Pathogenesis of nonarteritic anterior ischemic optic neuropathy

Based on histopathology, electron microscopic corrosion cast studies, optic nerve blood flow studies, and clinical data, the pathogenesis of idiopathic nonarteritic ischemic optic neuropathy includes the following features: (1) structurally crowded optic discs are predisposed; (2) laminar and retrolaminar regions are the most common locations for infarction; (3) there is flow impairment in the prelaminar optic disc during the acute phase; (4) lack of consistent choroidal flow impairment and the retrolaminar location of infarcts suggest vasculopathy within or distal to the paraoptic branches of the posterior choroidal arteries; (5) diabetes is the most consistently identified vasculopathic risk factor; (6) impaired autoregulation of the disc circulation by atherosclerosis, with a possible contribution from serotonin and endothelin-mediated vasospasm, may play a role; and (7) progression may be caused by secondary cell death after the initial ischemic insult or compression from cavernous degeneration and mechanical axonal distortion.

Indocyanine green and fluorescein angiography in nonarteritic anterior ischemic optic neuropathy

PURPOSE

To assess the value of indocyanine green angiography (ICGA) for demonstrating choroidal vascular abnormalities in patients with nonarteritic anterior ischemic optic neuropathy (NAION).

METHODS

The authors compared the ICGA and fluorescein fundus angiography characteristics of peripapillary circulation in 11 patients with acute NAION. There were 7 men and 4 women; the age range for the patients was 36 years to 72 years (mean +/- SD, 47.7 +/- 10.76 years). The angiographic factors considered significant were delay of peripapillary choroidal filling in the vertical watershed zone, leakage from the optic disk, and absolute filling defects on the disk. The authors compared the incidence of a vertical peripapillary watershed zone in the eyes of the 11 patients with that in the normal eyes of 50 controls (age range, 44-79 years) who had unilateral age-related macular degeneration.

RESULTS

Indocyanine green angiography revealed a peripapillary watershed zone in 8 of 11 patient eyes and 23 of 50 control eyes. There was no statistical difference in the number of eyes affected in each group (chi2 = 0.53; P = 0.47). Fluorescein fundus angiography showed leakage from the disk in 10 of 11 patients, whereas ICGA highlighted this problem in only 7 of the patients. The choroidal filling time of the watershed zones was significantly longer with ICGA (t = 3.13; P = 0.011).

CONCLUSION

Although ICGA allows better visualization of the choroidal watershed zones associated with NAION, it did not reveal any significantly different incidence of vertical choroidal watershed zone encompassing the optic disk for patients with NAION and controls. Fluorescein fundus angiography better visualized leakage from the disk in the patient group. These findings indicate that ICGA offers no significant advantage in terms of clinical diagnosis and management of NAION.

Vasospasm, its role in the pathogenesis of diseases with particular reference to the eye

Vasospasm can have many different causes and can occur in a variety of diseases, including infectious, autoimmune, and ophthalmic diseases, as well as in otherwise healthy subjects. We distinguish between the primary vasospastic syndrome and secondary vasospasm. The term "vasospastic syndrome" summarizes the symptoms of patients having such a diathesis as responding with spasm to stimuli like cold or emotional stress. Secondary vasospasm can occur in a number of autoimmune diseases, such as multiple sclerosis, lupus erythematosus, antiphospholipid syndrome, rheumatoid polyarthritis, giant cell arteritis, Behcet's disease, Buerger's disease and preeclampsia, and also in infectious diseases such as AIDS. Other potential causes for vasospasm are hemorrhages, homocysteinemia, head injury, acute intermittent porphyria, sickle cell disease, anorexia nervosa, Susac syndrome, mitochondriopathies, tumors, colitis ulcerosa, Crohn's disease, arteriosclerosis and drugs. Patients with primary vasospastic syndrome tend to suffer from cold hands, low blood pressure, and even migraine and silent myocardial ischemia. Valuable diagnostic tools for vasospastic diathesis are nailfold capillary microscopy and angiography, but probably the best indicator is an increased plasma level of endothelin-1. The eye is frequently involved in the vasospastic syndrome, and ocular manifestations of vasospasm include alteration of conjunctival vessels, corneal edema, retinal arterial and venous occlusions, choroidal ischemia, amaurosis fugax, AION, and glaucoma. Since the clinical impact of vascular dysregulation has only really been appreciated in the last few years, there has been little research in the according therapeutic field. The role of calcium channel blockers, magnesium, endothelin and glutamate antagonists, and gene therapy are discussed.

The diagnostic challenge of occult large vessel ischemia of the retina and choroid

Vascular occlusions of the retina and choroid can cause severe visual loss. These occlusions can occur as a result of systemic disease or after surgery. In most cases, the retinal appearance provides evidence of ischemia as the cause of visual loss. On occasion, however, clinical examination shows no objective signs of vascular occlusion, and this can lead the clinician to suspect optic nerve pathology as the cause of visual loss. This paper outlines some of the diagnostic criteria, clinical findings, and ancillary studies that can be used to differentiate between occult occlusion of the retina or choroid and optic nerve disease.