Anterior ischemic optic neuropathy is not associated with carotid artery atherosclerosis

Non-Arteritic Anterior Ischemic Optic Neuropathy (NA-AION): A Comprehensive Overview

Non-arteritic anterior ischemic optic neuropathy (NA-AION) represents one of the most important causes of blindness or severely impaired vision in middle-aged and elderly people. Unilateral optic disc edema and abrupt, painless vision loss are its defining features. It is commonly assumed that NA-AION is caused by an ischemic infarction of the optic nerve head, and, although the exact pathogenesis is still unknown, several risk factors and comorbidities associated with its development have been found. NA-AION occurs generally in patients older than 50 years who have small optic discs and vasculopathy risk factors. Even though numerous treatment options have been proposed, no available effective medical or surgical therapy or prophylactic measure for NA-AION currently exists. The purpose of present-day therapeutic strategies is therefore to identify and possibly control any underlying modifiable risk factors, aiming to prevent the development of new NA-AION episodes in the affected and fellow eye. A thorough assessment of NAION, including its history, epidemiology, etiology, pathophysiology, risk factors, associated comorbidities, clinical findings, diagnostic tests, treatment choices, prognosis, and future research, is the goal of this work.

Non-Arteritic Anterior Ischemic Optic Neuropathy (NA-AION): A Comprehensive Overview

Non-arteritic anterior ischemic optic neuropathy (NA-AION) represents one of the most important causes of blindness or severely impaired vision in middle-aged and elderly people. Unilateral optic disc edema and abrupt, painless vision loss are its defining features. It is commonly assumed that NA-AION is caused by an ischemic infarction of the optic nerve head, and, although the exact pathogenesis is still unknown, several risk factors and comorbidities associated with its development have been found. NA-AION occurs generally in patients older than 50 years who have small optic discs and vasculopathy risk factors. Even though numerous treatment options have been proposed, no available effective medical or surgical therapy or prophylactic measure for NA-AION currently exists. The purpose of present-day therapeutic strategies is therefore to identify and possibly control any underlying modifiable risk factors, aiming to prevent the development of new NA-AION episodes in the affected and fellow eye. A thorough assessment of NAION, including its history, epidemiology, etiology, pathophysiology, risk factors, associated comorbidities, clinical findings, diagnostic tests, treatment choices, prognosis, and future research, is the goal of this work.

Perioperative Ischemic Optic Neuropathy after Cardiac Surgery: Development and Validation of a Preoperative Risk Prediction Model

OBJECTIVE

Previous studies identified risk factors for ischemic optic neuropathy (ION) after cardiac surgery; however, there is no easy-to-use risk calculator for the physician to identify high-risk patients for ION before cardiac surgery. The authors sought to develop and validate a simple-to-use predictive model and calculator to assist with preoperative identification of risk and informed consent for this rare but serious complication.

DESIGN

Retrospective case-control study.

SETTING

Hospital discharge records.

PATIENTS

A total of 5,561,177 discharges in the National Inpatient Sample >18 years of age, with procedure codes for coronary artery bypass grafting, heart valve repair/replacement, or left ventricular assist device insertion.

INTERVENTIONS

All patients had undergone cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Known preoperative risk factors for ION after cardiac surgery were assessed to develop a risk score and prediction model. This model was validated internally using the split-sample method. There were 771 cases of ION among 5,561,177 patients in the National Inpatient Sample. The risk factors for ION used in the model were carotid artery stenosis, cataract, diabetic retinopathy, macular degeneration, glaucoma, male sex, and prior stroke; whereas uncomplicated diabetes decreased risk. With the internal validation, the predictive model had an area under the receiver operating characteristic curve of 0.66. A risk score cutoff ≥3 had 98.4% specificity.

CONCLUSIONS

This predictive model, based on previously identified preoperative factors, predicted risk of perioperative ION with a fair area under the receiver operating characteristic curve. This predictive model could enable screening to provide a more accurate risk assessment for ION, and consent process for cardiac surgery.

Associations among Stroke, Myocardial Infarction, and Amaurosis Fugax in a Tertiary Referral Hospital in Taiwan

Background: To determine the associations among carotid stenosis, stroke, and myocardial infarction (MI) in patients with amaurosis fugax (AF). Methods: We retrospectively reviewed the records of patients diagnosed as having AF between January 2000 and December 2019. Among 14,857 patients with AF initially reviewed in the database, only 173 were ultimately enrolled, after excluding patients with wrong diagnosis, insufficient medical records, or loss of follow-up. Results: Of the 173 patients with AF, 61 (35.3%) had carotid stenosis, and among them, 18 (10.4%) had severe stenosis. In multivariate regression analysis, carotid stenosis was significantly associated with age (p = 0.009), male sex (p = 0.006), and ischemic heart disease (p = 0.039). Sixteen (9.2%) patients experienced a stroke after AF diagnosis (mean time to stroke: 23.1 ± 31.1 months, range: 1 day~85 month), 11 (68.8%) of whom had carotid artery stenosis (p = 0.003). Three (1.7%) patients had MI after AF (mean time to MI: 24.8 ± 35.9 months, range: 12 days~66 months), none of whom had carotid artery stenosis (p = 0.553). Four (2.3%) patients had central retinal artery occlusion (CRAO) after AF, all of whom had carotid artery stenosis (p = 0.034). Conclusions: A high incidence of internal carotid artery stenosis was observed after AF attack and was significantly associated with stroke. The incidence of MI and CRAO after AF was low. Among them, only CRAO was associated with carotid artery stenosis.

Risk Factors for Non-arteritic Anterior Ischemic Optic Neuropathy: A Large Scale Meta-Analysis

Objective: We conducted a meta-analysis to explore all the potential risk factors for non-arteritic anterior ischemic optic neuropathy (NAION) based on the published literature. Methods: A comprehensive literature search through the online databases was performed to obtain studies concerning the risk factors of NAION up to June 2020. Pooled unadjusted odds ratios (ORs) or rate ratios (RRs) were calculated to evaluate the weight of risk factors. This study was registered in PROSPERO under the number CRD42018084960. Results: Our meta-analysis included 49 original studies comprising of more than 10 million patients. The following risk factors were proved to be significantly associated with NAION: male gender (OR = 1.67, 95% CI: 1.50-1.85, P < 0.00001), hypertension (RR = 1.28, 95% CI: 1.20-1.37, P < 0.00001), hyperlipidemia (RR = 1.43, 95% CI: 1.26-1.62, P < 0.00001), diabetes mellitus (DM) (RR = 1.53, 95% CI: 1.36-1.73, P < 0.00001), coronary heart disease (CHD) (RR = 1.68, 95% CI: 1.24-2.27, P = 0.0008), sleep apnea (RR = 3.28, 95% CI: 2.08-5.17, P < 0.00001), factor V Leiden heterozygous (RR = 2.21, 95% CI: 1.19-4.09, P = 0.01), and medication history of cardiovascular drugs. Conclusion: We concluded that the above risk factors were significantly related to NAION. Better understanding of these risk factors in NAION can help the direct therapeutic approaches.

Implication of Retrobulbar and internal carotid artery blood-flow-volume alterations for the pathogenesis of non-arteritic anterior ischemic optic neuropathy

Background

To analyze blood flow volume alteration that involved both retrobulbar artery and internal carotid artery (ICA) in patients with non-arteritic anterior ischemic optic neuropathy (NAION) and to assess their relevance for the pathogenesis of NAION.

Methods

Forty two patients with NAION (unilateral affected) and 42 age-matched controls participated in this study. By head-and-neck computed tomographic angiography (CTA), the diameter of ICA and ophthalmic artery (OA) were measured. By colour Doppler imaging (CDI), the mean blood flow velocity (Vm) and the blood flow volume of ICA and OA were measured or calculated. By optical coherence tomography angiography (OCTA), peripapillary and optic disc vessel density were measured. Data obtained from the affected side of the patients were compared to those of the contralateral healthy side and the control.

Results

Compared with the controls and the contralateral healthy side of the patients with NAION, the diameter of ICA, the blood flow volume of ICA and OA, the peripapillary and optic disc vessel density in the affected side decreased significantly (p < 0.05). However, there was no statistical difference in the diameter of OA (p = 0.179, 0.054 respectively), the Vm of OA (p = 0.052, 0.083 respectively), or the Vm of ICA (p = 0.364, 0.938 respectively) between groups. Peripapillary and optic disc vessel density were significantly positive correlated with the blood flow volume in ipsilateral ICA and OA in patients with NAION (all p < 0.01).

Conclusions

The reduction of blood flow volume was more prominent in OA and ICA than decrease of Vm, peripapillary and optic disc vessel density were significantly positive correlated with the blood flow volume of ipsilateral ICA and OA in patients with NAION.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02075-2.

Non-Arteritic Anterior Ischaemic Optic Neuropathy - Myths and Misconceptions: Experience from a Tertiary Care Centre in North India

We prospectively evaluated 22 consecutive patients (24 eyes) suffering from non-arteritic anterior ischaemic optic neuropathy (NAION) at a tertiary care centre in Northern India. The mean age was 51.7 years. Visual loss on awakening was noticed only in three (12.5%) eyes. Six (27.3%) patients had headache while three (9.7%) patients had retro-orbital pain at the onset of visual loss. Peripapillary haemorrhages were seen in two (8.3%) eyes. At follow up, only one eye showed improvement in visual acuity. The results of our study suggest that NAION may not always present with the classic clinical picture. Accordingly, a high index of suspicion remains the key to correct diagnosis.

Ischemic Optic Neuropathy

PURPOSE OF REVIEW

Vision is often threatened or lost by acute ischemic damage to the optic nerves. Such pathology most often affects the anterior portion of the nerve and is visible on funduscopic examination. Ischemic optic neuropathy is associated with typical vascular risk factors and with one systemic disease in particular: giant cell arteritis (GCA). This article provides an overview of the three major classes of ischemic optic neuropathy, including information on risk factors, differential diagnosis, evaluation, and management.

RECENT FINDINGS

Optical coherence tomography provides precise anatomic imaging in ischemic optic neuropathy, showing neural loss weeks before it is visible on examination. Refinements of optical coherence tomography reveal optic nerve microvasculature and may assist in understanding pathogenesis and verifying diagnosis. New diagnostic algorithms and cranial vascular imaging techniques help define the likelihood of GCA in patients with ischemic optic neuropathy. Finally, intraocular drug and biological agent delivery holds promise for nonarteritic ischemic optic neuropathy, whereas newer immunologic agents may provide effective steroid-sparing treatment for GCA.

SUMMARY

It is essential to recognize ischemic optic neuropathy upon presentation, especially to determine the likelihood of GCA and the need for immediate steroid therapy. A broad differential diagnosis should be considered so as not to miss alternative treatable pathology, especially in cases with retrobulbar optic nerve involvement.

Research on Association of the Diameter of the Internal Carotid Artery Siphon and Nonarteritic Anterior Ischaemic Optic Neuropathy

Objective

To investigate the association of the diameter of the internal carotid artery siphon (ICAS) and nonarteritic anterior ischaemic optic neuropathy (NAION).

Methods

Thirty patients clinically diagnosed with NAION (unilateral affected) who presented to Beijing Friendship Hospital from January 2017 to October 2018 were selected. The eyes suffered from NAION were enrolled as the observation group, and the fellow healthy eyes were enrolled as the control group. The following indexes were measured: diameter of the ICAS and the ophthalmic artery (OA), intima-media thickness (IMT) of the internal carotid artery (ICA), degree of stenosis of the ICA and plaque formation, and hemodynamic parameters of the ICA and the short posterior ciliary arteries (SPCAs). All the values were compared between the two groups.

Results

The diameter of the ICAS in the observation group (0.30 ± 0.07 cm) significantly narrowed compared with that of the control group (0.32 ± 0.06 cm) (P < 0.05), but the diameter of the OA of the two groups had no significant difference. The detection rate of carotid atherosclerosis plaque, the average blood flow velocity (Vm), and the resistance index (RI) of the ICA in the observation group (46.67%, 26.81 ± 1.78 cm/s, and 0.72 ± 0.06) had significant differences compared with those of the control group (16.67%, 28.19 ± 2.75 cm/s, and 0.70 ± 0.05) (P < 0.05), but the gradings of ICA stenosis and IMT between the two groups had no significant differences. The peak systolic velocity (PSV) and the end diastolic velocity (EDV) of the SPCAs in the observation group (10.72 ± 2.88 cm/s and 3.43 ± 1.01 cm/s) were significantly lower than those of the control group (13.62 ± 3.93 cm/s and 4.59 ± 1.71 cm/s) (P < 0.05), but the RI of the SPCAs of the two groups had no significant differences.

Conclusion

The diameter of the ICAS has a close relationship with NAION.

Carotid artery intimal medial thickness and carotid artery plaques in hypertensive patients with non-arteritic anterior ischaemic optic neuropathy

PURPOSE

To assess the correlation of carotid artery intimal medial thickness (C-IMT) and carotid artery plaque score (CPS) of the common carotid artery with non-arteritic anterior ischemic optic neuropathy (NAION) in hypertensive patients.

METHODS

This case-control study recruited 192 subjects. Forty-eight patients had NAION with systemic hypertension, 46 had hypertension without visual complaints, and 98 were normal controls. C-IMT and common carotid arterial plaque were measured by high-resolution vascular ultrasonography.

RESULTS

High-density lipoprotein (HDL) in patients with NAION (1.24 ± 0.31) was significantly lower than that of the Hypertensive group (1.39 ± 0.30, P = 0.034). The C-IMT in the affected side of patients with NAION (1.00 ± 0.23) was significantly increased compared to the unaffected side (0.83 ± 0.19, P < 0.001), the Hypertensive group (0.83 ± 0.17, P < 0.001), and the Normal group (0.69 ± 0.16, P < 0.001). The presence of carotid artery plaque was more frequent in the patients with NAION, compared to either the Hypertensive group (P = 0.001) or the Normal group (P < 0.001). By multiple regression analysis, lower high-density lipoprotein (HDL) (P = 0.009), thicker C-IMT (P = 0.002), CPS Grade = 1 (P = 0.028), and Grade = 2 (P = 0.005) were associated with increased NAION risk, when the NAION group compared with the Hypertensive group (OR > 1.0). Systolic blood pressure (P = 0.001), thicker C-IMT (P < 0.001), CPS Grade = 1 (P = 0.006), Grade = 2 (P = 0.002), and Grade = 3 (P = 0.015) were associated with increased NAION risk, when the NAION group compared with the Normal group (OR > 1.0).

CONCLUSIONS

C-IMT and CPS were associated with NAION in hypertensive patients, suggesting that NAION might be associated with carotid artery atherosclerosis. This association may be due to similar pathological changes of the inner vascular walls in the carotid artery and the arteries supplying the optic nerve head.

New Treatments for Nonarteritic Anterior Ischemic Optic Neuropathy

Despite increasing knowledge about the risk factors and clinical findings of nonarteritic anterior ischemic optic neuropathy (NAION), the treatment of this optic neuropathy has remained limited and without clear evidence-based benefit. Historical treatments of NAION are reviewed, beginning with the Ischemic Optic Neuropathy Decompression Trial. More recent treatments are placed within the historical context and illustrate the need for evidence-based therapy for ischemic optic neuropathy.

Levodopa as a possible treatment of visual loss in nonarteritic anterior ischemic optic neuropathy

PURPOSE

To determine the clinical effectiveness and potential neuroprotection of levodopa in improving visual acuity, visual field, and retinal nerve fiber layer (RNFL) thickness in eyes affected by NAION.

METHOD

Retrospective cohort study involving 59 eyes of 59 participants with NAION who were evaluated within 15 days of NAION onset. Participants received 25 mg carbidopa/100 mg levodopa three times daily with meals for 12 weeks (levodopa group) or were untreated (control group). Best-corrected visual acuity converted to logMAR, mean deviation (MD) threshold sensitivity on automated perimetry, and mean RNFL thickness on optical coherence tomography (OCT) were assessed. The primary outcome was the categorization of eyes into improved visual acuity (by 0.3 logMAR difference), worsened visual acuity (by 0.3 logMAR difference), or no change in visual acuity. The proportions in each category were compared between the levodopa and control groups.

RESULTS

Among participants with 20/60 or worse initial visual acuity, levodopa-treated participants had significant improvement (P < 0.0001) in the mean change from initial to final logMAR visual acuity of -0.74 ± 0.56 (95 % CI, -0.98 to -0.50), while the mean change for the control group at -0.37 ± 1.09 (95 % confidence interval estimate, -1.00 to +0.26) was not significant (P = 0.23). A significant difference between groups was observed (P = 0.0086) such that 19/23 (83 %) in the levodopa group improved and none got worse, as compared with 6/14 (43 %) in the control group improving while four (29 %) worsened. The change in visual field MD and RNFL thickness on OCT showed no significant difference at P = 0.23 and P = 0.75 respectively. No levodopa-treated participant had any adverse event from the levodopa.

CONCLUSIONS

Treatment within 15 days of onset of NAION with levodopa improved central visual acuity by an average of 6 lines on Snellen acuity chart. Levodopa may promote neuroprotection of the maculopapular retinal ganglion cell fibers in NAION.

Nonarteritic anterior ischemic optic neuropathy

OPINION STATEMENT

Currently there is no generally accepted, well-proven treatment for nonarteritic anterior ischemic optic neuropathy (NAION). Most proposed treatments are empirical and include antithrombotics, vasodynamic agents, treatments aimed at reducing optic disc edema, and various neuroprotective strategies. Most potential treatments have been inadequately studied, prematurely embraced, or prematurely discarded. Evidence for antithrombotic agents is lacking, and small vessel arterial occlusion has never been demonstrated in NAION. Antiplatelet agents have not been studied in acute NAION, but they are often prescribed for acute treatment because of their proven role in stroke prevention. Because NAION is an ischemic disorder occurring more often after the age of 50 in patients with vascular risk factors, I recommend aggressive risk-factor management and antiplatelet therapy. The evidence that aspirin can help to prevent NAION in the fellow eye is divided. I recommend aspirin for secondary prevention, mostly for its proven role in stroke prevention. NAION occurs in patients with physiologically crowded optic nerves and small cup-to-disc ratios. Disc edema may contribute to a "compartment syndrome," which compresses the fine capillary blood supply of the optic nerve head, resulting in ischemia and axonal damage. There is some limited and debatable evidence that oral steroids may shorten the duration of disc edema and improve visual outcome in NAION. I discuss this evidence with patients who present acutely with NAION, and although I consider prescribing oral steroids on a case-by-case basis, I will not routinely recommend oral steroids until a properly randomized clinical trial is performed. Some neuroprotective strategies have been studied, but none have proven to be helpful. Although some (eg, brimonidine) are probably not harmful, I do not recommend these treatments. Early referral to low vision services may help to improve functional visual outcome.

Lesions of the optic nerve

As experts on the central nervous system, neurologists are expected to be familiar with the many conditions that can result in visual loss arising from lesions of the optic nerve. The optic nerves are unique central nervous system structures in terms of surrounding anatomy, size, location, and blood supply; therefore, they are uniquely vulnerable to every pathological process that can affect the central and peripheral nervous systems, including inflammation, ischemia, compression, infiltration, toxic or hereditary metabolic dysfunction, trauma, and mechanical damage. This chapter highlights the importance of being able to identify the historical and clinical features that will enable neurologists to narrow down the broad differential diagnosis of optic nerve lesions. Distinguishing an optic neuropathy on the basis of history and clinical examination alone, however, can be difficult, especially when bilateral optic neuropathies are present. Specific ancillary tests, especially new imaging modalities, help further localization and differential diagnosis.

Perioperative visual loss: what do we know, what can we do?

Perioperative visual loss (POVL), a rare, but devastating complication, can follow non-ocular surgery. Highest rates of visual loss are with cardiac and spine surgery. The main causes of visual loss after non-ocular surgery are retinal vascular occlusion and ischaemic optic neuropathy. This review updates readers on the incidence, suspected risk factors, diagnosis, and treatment of POVL due to these conditions.

Treatment of nonarteritic anterior ischemic optic neuropathy

Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common clinical presentation of acute ischemic damage to the optic nerve. Most treatments proposed for NAION are empirical and include a wide range of agents presumed to act on thrombosis, on the blood vessels, or on the disk edema itself. Others are presumed to have a neuroprotective effect. Although there have been multiple therapies attempted, most have not been adequately studied, and animal models of NAION have only recently emerged. The Ischemic Optic Neuropathy Decompression Trial, the only class I large multicenter prospective treatment trial for nonarteritic anterior ischemic optic neuropathy, found no benefit from surgical intervention. One recent large, nonrandomized controlled study suggested that oral steroids might be helpful for acute NAION. Others recently proposed interventions are intravitreal injections of steroids or anti-vascular endothelial growth factor (anti-VEGF) agents. There are no class I studies showing benefit from either medical or surgical treatments. Most of the literature on the treatment of NAION consists of retrospective or prospective case series and anecdotal case reports. Similarly, therapies aimed at secondary prevention of fellow eye involvement in NAION remain of unproven benefit.

Ischemic optic neuropathies

Anterior ischemic optic neuropathy (AION) is the most common cause of acute optic neuropathy after age 50, but may also occur in younger patients. The diagnosis is clinical and includes painless visual loss associated with a relative afferent pupillary defect and disc edema. In almost all cases, there is an underlying crowded optic nerve with a small cup-to-disc ratio. The visual prognosis is usually poor, although up to 43% of patients may improve over time. The fellow eye is involved in up to 15% of patients within 5 years, but the risk of recurrence in the same eye is less than 5%. There is no treatment for acute nonarteritic AION but it is essential to evaluate these patients for underlying treatable atheromatous vascular risk factors. A coagulation workup should also be considered in younger patients. It is essential to rule out giant cell arteritis in all patients over the age of 50 with ischemic optic neuropathies. Posterior ischemic neuropathy (in which the optic nerve is normal acutely) is rare and should be considered a diagnosis of exclusion.

Risk factors for severe cranial ischaemic events in an Italian population-based cohort of patients with giant cell arteritis

OBJECTIVE

To evaluate the impact of traditional cardiovascular risk factors, carotid atherosclerosis and the effect of anti-platelet/anti-coagulant therapy on the occurrence of severe cranial ischaemic events (CIEs) in GCA.

METHODS

We identified 180 Reggio Emilia (Italy) residents with biopsy-proven GCA diagnosed between 1986 and 2005. We evaluated data on demographics, clinical features, laboratory investigations, cardiovascular risk factors, anti-platelet/anti-coagulant use and carotid atherosclerosis.

RESULTS

Systemic signs/symptoms were significantly less frequent (P = 0.004) and ESR and C-reactive protein (CRP) values at diagnosis were significantly lower (P = 0.03 and P = 0.04, respectively) in patients with CIEs. The prevalence of hypertension and ischaemic heart disease was significantly higher in patients with CIEs than in those without (P = 0.01 and P = 0.006, respectively). Patients treated with anti-platelet/anti-coagulant therapy were significantly more likely to suffer CIEs than those without (P = 0.03), while CIEs were significantly associated with ischaemic heart disease in this subset of patients (P = 0.02). By multivariate logistic regression, we found that the best predictors for the development of severe CIEs included the absence of high (>5.38 mg/dl) CRP levels at diagnosis (OR = 0.31, 95% CI 0.08, 1.20), the absence of systemic manifestations (OR = 0.30, 95% CI 0.08, 1.08), the presence of hypertension (OR = 7.77, 95% CI 0.83, 72.76), and a past history of ischaemic heart disease (OR = 8.65, 95% CI 0.92, 80.95).

CONCLUSIONS

In GCA, hypertension, a past history of ischaemic heart disease and a low inflammatory response are associated with a higher risk of developing severe CIEs.

[A case of nonarteritic anterior ischemic optic neuropathy with hypertension, diabetes mellitus, hyperlipidemia and severe stenosis of the internal carotid artery]

A 76 year-old man had had hypertension, diabetes mellitus and hyperlipidemia since 1985, and bruit in his left neck since 1993. He had abrupt decrease in left visual acuity on November 24, 2005, and visited an ophthalmologist. On November 28, his corrected visual acuity was 1.0 in the right and 0.1 in the left. The examination of optic fundi showed ear-side edema of the left optic disk. Fluorescence examination of the left optic fundus showed delay in early filling and later hyperfluorescence. Goldman visual field examination showed horizontal lower semiblindness. Since he did not complain of eye pain, his blood examination showed no reaction of inflammation, and he had hypertension, diabetes mellitus and hyperlipidemia, anterior ischemic optic neuropathy was diagnosed. The treatment with aspirin, alprostadil and prednisolone transiently improved the optic fundi and visual acuity, but his left visual acuity returned to 0.1. Carotid ultrasonography showed 95 percent stenosis in the left internal carotid artery. As there is no established treatment for ischemic optic neuropathy, the management of risk factors is most important.

Ischemic Optic Neuropathy: Incidence, Clinical Profile and Long-Term Prognosis in Qatar

Background: Ischemic optic neuropathy (ION) is the most common optic neuropathy in patients over the age of 50 years. It has variable clinical features, prognosis and associated risk factors. As far as we know there are no published data about ION from other Arabic countries.

Objective: We describe the clinical presentation, associated risk factors and the prognosis in patients presenting to our hospital and compare our findings with USA studies.

Methods: In a hospital-based prospective study, consecutive patients with a diagnosis of ION seen between January 2001 and December 2004 were included. Detailed neuro-ophthalmic evaluation, laboratory and neuroradiological investigations were performed in all patients. The patients were followed up at the clinic for mean period of 18 months.

Results: Twenty-six patients, 21 males and 5 females (male to female ratio 4.2:1) were enrolled. Mean age was 50.3years. The incidence was calculated as 1/100,000/year. Anterior ION was the commonest type (88%). Vascular risk factors were common; e. g. diabetes mellitus (DM) (58%), hypertension (HTN) (42%), hypercholesterolemia (10%). Prevalence of disc-at-risk (small or absent physiological cup) was (16%) and of temporal arteritis was uncommon (4%). Brain MRI showed ischemic vascular changes in (29%).

Conclusion: The incidence of ION in Qatar is much less and showed male predominance when compared with data from USA. Anterior non-arteritic ION is the commonest type. Vascular risk factors were more common while prevalence of disc at-risk and temporal arteritis was less compared to USA studies while DM was higher. Therefore, controlling risk factors may reduce the incidence of ION.

Neuro-Ophthalmic Emergencies for the Neurologist

A variety of acute neurologic disorders present with visual signs and symptoms. In this review the authors focus on those disorders in which the clinical outcome is dependent on timely and accurate diagnosis. The first section deals with acute visual loss, specifically optic neuritis, ischemic optic neuropathy (ION), retinal artery occlusion, and homonymous hemianopia. The authors include a discussion of those clinical features that are helpful in distinguishing between inflammatory and ischemic optic nerve disease and between arteritic and nonarteritic ION. The second section concerns disc edema with an emphasis on the prevention of visual loss in patients with increased intracranial pressure. The third section deals with abnormal ocular motility, and includes orbital inflammatory disease, carotid-cavernous fistulas, painful ophthalmoplegia, conjugate gaze palsies, and neuromuscular junction disorders. The final section concerns pupillary abnormalities, with a particular emphasis on the dilated pupil and on carotid artery dissection. Throughout there are specific guidelines for the management of these disorders, and areas are highlighted in which there is ongoing controversy.

Ocular findings as predictors of carotid artery occlusive disease: is carotid imaging justified?

OBJECTIVES

Hemispheric neurologic symptoms, amaurosis fugax, and Hollenhorst plaques at eye examination are standard indications for carotid imaging to identify carotid artery occlusive disease (CAOD). Previous reports have suggested that other ocular findings, such as retinal artery occlusion and anterior ischemic optic neuropathy, are associated with CAOD. However, the predictive value of ocular findings for the presence of CAOD is controversial. The purpose of this study was to define the predictive value of ocular symptoms and ophthalmologic examination in identifying significant CAOD.

METHODS

Over 3 years 145 patients were referred for carotid imaging on the basis of ocular indications in 160 eyes. Forty patients were excluded because of concurrent non-ocular indications for carotid imaging, leaving 105 patients referred exclusively for ocular indications to evaluate. Ophthalmologic history and eye examination were correlated with carotid duplex ultrasound findings.

RESULTS

Amaurosis fugax was associated with a positive scan in 20.0% of carotid arteries (P =.022). Hollenhorst plaques at fundoscopic examination were associated with a positive scan in 18.2% of carotid arteries (P =.02). Ocular findings exclusive of Hollenhorst plaques were particularly poor predictors of CAOD, inasmuch as only 1 of 64 arteries (1.6%) had significant ipsilateral internal carotid artery stenosis (P =.022). Venous stasis retinopathy was the only ocular finding other than Hollenhorst plaques with any predictive value (1 of 5 scans positive; positive predictive value, 20.0%).

CONCLUSIONS

Ocular symptoms and findings are poor predictors of CAOD. Amaurosis fugax, Hollenhorst plaques, and venous stasis retinopathy demonstrated moderate predictive value, whereas all other ocular findings demonstrated no predictive value in identifying CAOD.

Ischemic optic neuropathies

PURPOSE OF REVIEW

To review recent clinical data on ischemic optic neuropathies, which are some of the most frequently encountered optic neuropathies. These disorders include nonarteritic anterior ischemic optic neuropathy, arteritic anterior ischemic optic neuropathy, and posterior ischemic optic neuropathy.

RECENT FINDINGS

Recent studies have facilitated our understanding of the natural history of visual loss, recovery, and recurrence in these disorders. Additionally, the value of various diagnostic techniques and treatment options, particularly for arteritic anterior ischemic neuropathy, has been clarified.

SUMMARY

Application of the studies described in this paper should allow the clinician to more accurately diagnose ischemic optic neuropathies and counsel the patient with regard to appropriate management, prognosis for visual recovery and future risk of recurrence.

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.

Ischemic optic neuropathy as the first manifestation of elevated cholesterol levels in young patients

PURPOSE

To investigate the relationship between idiopathic nonarteritic ischemic optic neuropathy (NAION) and serum lipid levels in patients </= 50 years of age.

DESIGN

Case-control study.

PARTICIPANTS

Thirty-seven consecutive patients with NAION and 74 age- and gender-matched comparison patients.

METHODS AND MAIN OUTCOME MEASURES

Serum lipid levels and the presence of several historical diseases and exposures were abstracted from the medical records in cases and controls.

RESULTS

The mean total cholesterol level was significantly increased in patients with NAION compared with controls (235.4 vs. 204.0 mg/dl, P < 0.001). The odds ratio of having high blood cholesterol (>/= 240 mg/dl) with NAION was 3.3 (95% confidence interval, 1.4-7.8), and the likelihood increased when the comparison was restricted to nondiabetic patients. Diabetes mellitus was more common in cases than controls (P = 0.027), but systemic hypertension was not significantly different (P = 0.63). No patient (0 of 24) had a magnetic resonance imaging study consistent with optic neuritis or central nervous system demyelination. Visual improvement was uncommon.

CONCLUSIONS

This study demonstrates that hypercholesterolemia is associated with NAION in younger patients. NAION may be the first manifestation of a lipid disorder, a previously unrecognized syndrome. These patients have experienced a focal, microvascular central nervous system ischemic event at a relatively young age. Aggressive treatment of lipid abnormalities in these patients may be warranted.

Ocular and systemic findings and their correlation with hemodynamically significant carotid artery stenosis: a retrospective study

BACKGROUND

Optometrists often encounter patients with ocular signs and/or symptoms suggestive of carotid artery disease, but criteria for eye care practitioners concerning when to order carotid studies are not well established. A retrospective study in an optometry clinic was performed to determine if certain ocular findings and associated systemic risk factors were associated with hemodynamically significant carotid artery stenosis (HSCAS).

METHODS

A retrospective analysis was performed on all patients examined in the optometry clinic at the Sepulveda Ambulatory Care Center from January 1, 1998 through December 31, 1999 to identify all patients who had carotid studies ordered. Charts were then reviewed to determine the ocular finding that prompted the carotid study. Statistical analysis using an odds-ratio was performed to determine whether any ocular sign/symptom or systemic risk factor was associated with HSCAS.

RESULTS

Of 3822 patients, 48 (1.26%) had carotid studies ordered. Eight (17%) had HSCAS of >50% and symptomatic patients were 1.6 times more likely to have HSCAS than asymptomatic patients. Patients with HSCAS were 1.8 times more likely to have retinal vascular occlusions, 1.9 times more likely to have normotensive glaucoma, 2.4 times more likely to have peripheral retinal hemorrhages, and 2.6 times more likely to be smokers, although none of these factors were found to be a statistically significant indicator of HSCAS. However, the number of systemic diseases tended to be greater for the HSCAS patients compared with the non-HSCAS patients (HSCAS median = 3.5 and the non-HSCAS median = 2, p = 0.049).

CONCLUSION

Although no single ocular or systemic risk factor was found to be a statistically significant indicator of HSCAS, the number of systemic disease risk factors tended to be greater for the HSCAS patients compared with the non-HSCAS patients (p = 0.049). An extensive literature review was also performed to help establish guidelines for when to order carotid studies on the basis of ocular signs and/or symptoms as well as the presence of additive associated systemic risk factors.

Microemboli are not a prerequisite in retinal artery occlusive diseases

PURPOSE

Retinal artery occlusion (RAO) is caused by arterio-arterial or cardiovascular emboli in about 50% of all cases, but the role of non-embolic causes remains unclear.

SUBJECTS AND METHODS

We studied 27 patients with amaurosis fugax (AFX), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and anterior ischaemic optic neuropathy (AION). Patients underwent an evaluation of cerebrovascular and cardiovascular risk factors, measurement of haemorheological parameters, and Doppler/duplex sonography including ultrasound detection of cerebral microembolic signals and echocardiography.

RESULTS

Forty-one per cent of the patients had internal carotid atherosclerosis but only one patient had microembolic signals, probably due to a cardiac thrombus. Vascular risk factors, especially hypertension, were present in 82% of the patients correlating with abnormal haemorheological parameters such as increased thrombocyte reactivity.

CONCLUSIONS

Our results indicate that altered haemorheological parameters, especially increased thrombocyte reactivity and vascular risk factors such as arterial hypertension, are non-embolic causes of vascular disease in a significant number of patients with RAO. This should guide diagnostic and therapeutic considerations concerning RAO in cases without proven embolic sources.

Carotid endarterectomy in a patient with anterior ischemic neuropathy

A case of anterior ischemic optic neuropathy (AION) associated with 90% stenosis of the ipsilateral internal carotid artery (ICA) and diminished blood flow through the ophthalmic artery was studied. After carotid endarterectomy (CEA), the patient showed subjective and measurable improvement in vision and increased ophthalmic artery flows. This observation supports the role for screening carotid duplex scanning and transcranial Doppler in patients with AION. Early CEA in patients with associated ipsilateral ophthalmic artery hypoperfusion may improve visual outcome.

Participation in the Ischemic Optic Neuropathy Decompression Trial: sex, race, and age

BACKGROUND

The Ischemic Optic Neuropathy Decompression Trial (IONDT) is a randomized, single masked, multicenter trial designed to assess the safety and efficacy of optic nerve decompression surgery compared with careful follow-up in patients 50 years or older with non-arteritic anterior ischemic neuropathy (NAION).

OBJECTIVES

To examine and evaluate the sex, race, and age distributions of the screened, and subsequently enrolled, IONDT population, especially the proportions of female, minority, and elderly patients, and demographic characteristics of clinical center investigators, the geographical location of IONDT Clinical Centers, and the referral patterns of local physicians.

SETTING

Twenty-five U.S. clinical centers.

PARTICIPANTS

There were 1,681 referrals to the Clinical Centers; an Eligibility Screening Form providing demographic information was completed for 1,152.

FINDINGS

Forty-three percent (495/1,152) of screened cases were women. Seven percent (85/1,152) were minorities: 33 African-Americans, 34 Hispanics, 17 Asians, and 1 Native-American. The average age was 66 +/- 10 years with a range of 22-92 years of age. Of the 1,152 referred patients, 305 were eligible for randomization; 258 (85%) of these agreed to participate in the trial. The demographic makeup of the randomized IONDT patients was similar to that of the screened population.

CONCLUSIONS

Women and the elderly are well represented in the IONDT. Because the number of participating minorities was low, we cannot reliably assess their level of participation. Both a low incidence of NAION in minorities and a low referral rate of minorities to clinical trials are plausible explanations for our findings.

The effect of aspirin on the visual outcome of nonarteritic anterior ischemic optic neuropathy

PURPOSE

To examine the effect of aspirin use on the visual outcome of nonarteritic anterior ischemic optic neuropathy.

METHODS

This retrospective case-controlled study included 23 patients who used aspirin regularly before and during the course of nonarteritic anterior ischemic optic neuropathy and 55 control patients with nonarteritic anterior ischemic optic neuropathy. Snellen visual acuity in logMAR and mean deviation on automated perimetry were compiled from the initial and final follow-up examinations.

RESULTS

The comparisons of patients who took aspirin with control patients disclosed that neither initial logMAR (P = .36) nor the follow-up logMAR (P = .95) data differed significantly. There was no significant difference between the groups for the initial (P = .60) and the follow-up mean deviation (P = .41).

CONCLUSIONS

Aspirin use does not improve the visual outcome of patients with nonarteritic anterior ischemic optic neuropathy. Additional studies are needed to further elucidate this issue.

Anterior ischemic optic neuropathy

AION is the most common acute optic neuropathy in patients over 50 and, although the diagnosis is often straightforward, our methods for managing the associated visual loss are inadequate. Analysis of the wealth of information gained from recent clinical studies may move us closer to an effective therapy.