Purpose: To describe a patient with a unique retinal phenotype of probable Susac syndrome. Observations: A 47-year-old female who presented with bilateral tinnitus and vision changes was found to have bilateral sensorineural hearing loss and many bilateral retinal arteriolar Gass plaques. She had bilateral scotomas corresponding with temporal thinning and atrophy of the inner nuclear layer (INL) on OCT. Retinal examination and fluorescein angiography demonstrated minimal arteriolar wall hyperfluorescence with no evidence of acute branch retinal artery occlusion. She developed daily headaches. MRI of the brain was normal with no corpus callosal lesions. She was diagnosed with probable Susac syndrome based on the above findings. Conclusions and importance: Our patient’s bilateral high frequency sensorineural hearing loss, numerous bilateral Gass plaques, and headaches are most likely attributable to Susac syndrome. While BRAO is considered a cornerstone of retinal involvement in Susac syndrome, it may only be appreciable angiographically in the acute setting, and it is important to recognize Gass plaques as a significant diagnostic marker of disease.

Background: Susac syndrome is a vasculopathy, resulting in the classic triad of branch retinal artery occlusion (BRAO), inner ear ischemia, and brain ischemia. In this retrospective chart review, we characterize fluorescein angiography (FA) findings and other ancillary studies in Susac syndrome, including the appearance of persistent disease activity and the occurrence of new subclinical disease on FA. Methods: This multicenter, retrospective case series was institutional review board–approved and included patients with the complete triad of Susac syndrome evaluated with FA, contrasted MRI of the brain, and audiometry from 2010 to 2020. The medical records were reviewed for these ancillary tests, along with demographics, symptoms, visual acuity, visual field defects, and findings on fundoscopy. Clinical relapse was defined as any objective evidence of disease activity during the follow-up period after initial induction of clinical quiescence. The main outcome measure was the sensitivity of ancillary testing, including FA, MRI, and audiometry, to detect relapse. Results: Twenty of the 31 (64%) patients had the complete triad of brain, retinal, and vestibulocochlear involvement from Susac syndrome and were included. Median age at diagnosis was 43.5 years (range 21–63), and 14 (70%) were women. Hearing loss occurred in 20 (100%), encephalopathy in 13 (65%), vertigo in 15 (75%), and headaches in 19 (95%) throughout the course of follow-up. Median visual acuity at both onset and final visit was 20/20 in both eyes. Seventeen (85%) had BRAO at baseline, and 10 (50%) experienced subsequent BRAO during follow-up. FA revealed nonspecific leakage from previous arteriolar damage in 20 (100%), including in patients who were otherwise in remission. Of the 11 episodes of disease activity in which all testing modalities were performed, visual field testing/fundoscopy was abnormal in 4 (36.4%), MRI brain in 2 (18.2%), audiogram in 8 (72.7%), and FA in 9 (81.8%). Conclusions: New leakage on FA is the most sensitive marker of active disease. Persistent leakage represents previous damage, whereas new areas of leakage suggest ongoing disease activity that requires consideration of modifying immunosuppressive therapy.

Egan, Robert A. MD; Brown, Adam MD; Grillo, Eugenio MDEditor(s): Avery, Robert DO; Golnik, Karl C. MD; Froment, Caroline MD, PhD; Wang, An-Guor MD Author Information

INTRODUCTION:Coronavirus disease 2019 (COVID-19) has been recently associated with infarction of the central splenium of the corpus callosum. These are described as cytotoxic lesions, and imaging rarely reveals enhancement. They have not been described in the body or head of the corpus callosum. Few diseases affect the corpus callosum, but the most common include multiple sclerosis, aquaporin-4 disease, and Susac syndrome. There is also emerging literature on Mild Encephalopathy with Reversible Splenial lesions associated with central and not basal lesions. The reason for the location of these lesions in acute COVID-19 infection is unknown.CASE REPORT:A 22-year-old female presented to the ED for altered mental status after being found down. A brief history review indicated that the patient had been altered for 2-3 days before being found naked and covered in her own feces and urine by her family after they had not heard from her. As she lived alone, a clear history of the events preceding her admission remains unclear. On initial assessment, the patient was found to be somnolent and nonverbal, though she could follow simple commands. On admission, testing for SARS CoV-2 RNA PCR was positive. Patient was admitted to the hospital for further work up to determine the cause of the altered mental status.CONCLUSION:We present a new case of a young woman who developed a central splenium lesion during acute COVID-19 infection and explain the predilection for the callosum in these patients, as well as literature to show that COVID-19 was most likely the cause.

Nonarteritic anterior ischemic optic neuropathy (NAION) has no proven treatment and typically causes some degree of irreversible visual loss. Preventing second eye involvement is a worthy goal, but there is uncertainty regarding the benefit of any preventive therapy. Two experts debate the role of aspirin in preventing fellow eye involvement in NAION. Pro: Robert A. Egan, MD Nonarteritic anterior ischemic optic neuropathy (AION) is an idiopathic vasculopathy of the optic nerve and is the most common cause of acute optic neuropathy (1,2). Many studies have been conducted to determine causality, but none have been definitive. A link to certain systemic vascular risk factors has been suggested because there is an increased risk in AION of those factors including diabetes, hypertension, hypercholesterolemia, hypercoagulability, ischemic heart disease, and cerebrovascular disease (3–8). Because vision loss in the fellow eye can occur in up to 15% of patients with AION (9), a treatment to prevent second eye involvement has been sought. Given that vascular risk factors have been associated as noted above, aspirin has predictably been prescribed as this preventative measure. There is some evidence in the literature that supports this theory, although the number of published reports is sparse. Kupersmith et al (10) found in a retrospective trial that aspirin taken 2 or more times per week decreased the incidence and relative risk of second eye involvement (10). Beck et al found retrospectively that aspirin reduced the risk of second eye involvement and the effect was stronger in the first 2 years than at the first-year mark. The risk of second eye involvement was 7% in the aspirin group and 15% in the nonaspirin group at 2 years (11). The Ischemic Optic Neuropathy Decompression Trial (IONDT), a prospective study, enrolled 418 subjects and found that 14.7% developed second eye involvement during a follow-up period of 5.1 years. They also found that increased incidence of second eye involvement was not associated with aspirin usage. Furthermore, another retrospective trial showed that aspirin not only reduced the rate of second eye involvement, it also had a dose effect and was more beneficial at higher doses and also prolonged onset of second eye involvement (12). There is also evidence that aspirin does not improve the visual outcome of patients suffering with NAION (13). It is generally believed that prospective studies are more important and consequential than retrospective studies. However retrospective studies have their merit and their place in the scientific milieu. Aspirin has also been used for secondary prevention in other disorders. If we take simply ischemic cerebrovascular disease, there are a myriad of reports in the scientific literature demonstrating clear benefit of risk reduction with aspirin usage. If we extrapolate from the possibility that AION is associated with vascular risk factors, then treating these risk factors may help patients in other ways besides attempting to prevent second eye recurrence. The data regarding the benefits of secondary prevention of ischemic stroke with aspirin monotherapy are huge; there are countless studies in the medical literature. Aspirin plus clopidogrel seems to show some heightened benefit over aspirin monotherapy. A meta-analysis of 11 randomized controlled trials revealed a significant reduction in recurrent ischemic stroke (14). Another analysis of 16 randomized controlled trials showed a significant stroke risk reduction with dual antiplatelet therapy over aspirin monotherapy (15). Long-term dual antiplatelet therapy is also associated with more bleeding side effects and typically not recommended. This author has had personal and professional experience in early recurrence of second eye involvement. Steve Feldon was also quoted previously (9) as having a similar experience and has relayed that he found that this occurs within 18 months (personal communication). Because current medical thought is directed toward using dual antiplatelet therapy to reduce early ischemic stroke recurrence (14–16), it is possible that using combinations of the drugs aspirin plus clopidogrel for 6–12 months after onset of first eye involvement of AION may more significantly reduce the rate of second eye involvement. This of course has not been studied yet, but could be a direction for future research. Although the data in favor or prevention of second eye involvement with aspirin are based on only a few retrospective clinical trials, the potential benefits are great with low bleeding risk. The possible benefit of preventing other cerebrovascular accidents can also not be ignored. This author is in favor of treating patients with first or second eye involvement with aspirin therapy. Con: Anthony C. Arnold, MD The discussion of the use of ASA in patients with NAION includes 2 major aspects: 1) reduction of risk of subsequent cardiovascular events, and 2) reduction of risk of fellow eye NAION events. Basis for ASA use to reduce risk of cardiovascular events Aspirin (ASA) may have a 2-fold effect in reducing the risk of cardiovascular events: antithrombotic and anti-inflammatory. Aspirin inhibits platelet aggregation by its action to block thromboxane A2, which is effective at a low dose of 100 mg (17); it also has been shown to reduce the levels of proinflammatory cytokines and c-reactive protein (18). Multiple studies have demonstrated that ASA is effective in reducing the risk of myocardial infarction (MI), stroke, and vascular death in both men and women with pre-existing cardiovascular disease (secondary prevention) (17–19). For primary prevention (so-called “healthy” patients, without prior cardiovascular events, not eliminating patients with so called “vasculopathic risk factors” such as diabetes, hypertension, hyperlipidemia, or smoking), the Physicians' Health Study (20) concluded that low dose ASA therapy reduced the risk of MI in healthy men ≥50 years. Subsequent studies and meta-analyses (21) found that the benefit of low dose ASA in the reduction of combined risk of cardiovascular events extended to healthy men (MI) and women (ischemic stroke). However, the study of healthy British male doctors published contemporaneously did not find a significant benefit. Large scale recent studies have cast further doubt on the risk–benefit ratio for ASA for primary prevention. The Aspirin in Reducing Events in the Elderly (ASPREE) Study (22–24) in healthy men and women ≥70 years recently demonstrated an increased risk of major hemorrhagic events with no significant reduction in cardiovascular events or survival with the use of low dose ASA. Risk of cardiovascular events in patients with NAION NAION is often associated with vasculopathic risk factors, including hypertension, diabetes, hyperlipidemia, and obstructive sleep apnea, which may be expected to result in a higher risk of cardiovascular events in this patient group. The data, however, are mixed. Although Guyer et al (3), Sawle et al (25), and Hayreh et al (4) reported increased occurrence of MI or stroke, other large series by Ellenberger et al (26), Boghen et al (27), and Repka et al (28) did not. Studies assessing for carotid stenosis in patients with NAION (29,30) have not revealed an association. Recent papers from Asia remain mixed. Lee et al (31) reported an increased risk of ischemic stroke after NAION, whereas Park et al (32) did not. An issue in all of these studies is the distinction between NAION with and without the vasculopathic risk factors known to increase risk of stroke and MI. Although most studies were not powered to distinguish between groups with and without risk factors regarding cardiovascular events, Hayreh et al (4) did so and found that NAION alone was not associated with an increased risk. Moreover, as shown by studies listed in the previous section, the use of ASA for primary prevention, even in those with vasculopathic risk factors, is unproven. Basis for ASA use to reduce risk of NAION If we assume that there is a component of thrombosis in the pathogenesis of NAION, then antiplatelet therapy may be a logical approach to prevention. However, there is limited evidence for this. The pathogenesis of NAION and specifically the role of thrombosis has not been established. There has been a scattering of reports of NAION occurring in patients with the Factor V Leiden mutation and activated Protein C resistance, antithrombin III deficiency, antiphospholipid antibodies, and other disorders of the coagulation system (33,34), but only one systematic study has been performed. Salomon et al (12) examined the association of prothrombotic risk factors and NAION, finding none. A later study by the same group (35) found a platelet polymorphism in 16 of 92 patients with NAION, suggesting it as a possible risk factor, but there has been no corroboration by further study, and the clinical implications remain unclear. These disorders typically potentiate venous thrombosis and are treated with anticoagulant rather than antiplatelet therapy. Hyperhomocysteinemia has also been proposed as a risk factor for NAION, particularly in younger patients. Although it may have implications for platelet activity in addition to direct endothelial damage, the studies assessing the link to NAION have produced conflicting results. Kawasaki et al (36), Pianka et al (37), Weger et al (38), and Glueck et al (39) suggested an association, but Biousse et al (40) and Salomon et al (7), in a much larger controlled study, did not. Moreover, the treatment of hyperhomocysteinemia, whether related to the methylenetetrahydrofolate reductase (MTHFR) C677T mutation or not, involves folate supplementation. No studies have assessed the benefit of ASA use in reducing fellow eye involvement in patients with platelet polymorphisms or hyperhomocysteinemia. Risk of fellow eye involvement in NAION Does the risk of fellow eye involvement after NAION justify intervention? Early studies of the frequency of second eye occurrence ranged from 24% to 48% (26,28), with variance of methodology and length of follow-up confounding the results. In planning for a prospective study of ASA for fellow eye prophylaxis after unilateral NAION, Beck et al reviewed data from 431 patients with NAION, finding a 2-year risk for fellow eye involvement of 9%–12%, with 5-year risk of 12%–19% (11) The subsequent follow-up data from the IONDT suggested a similar 5-year fellow eye involvement rate of 15% (9). Evidence that ASA reduces fellow eye involvement in NAION The data from Beck et al revealed that a viable prospective study would require enrollment of 4,000 patients, an infeasible goal; the study was not pursued, and no prospective data are available regarding the benefit of ASA in reducing fellow eye involvement after NAION. Beck et al did review the question retrospectively in their review of 431 patients, finding that the 5-year risk was 10%–17% with ASA and 13%–20% without, not significantly different. The IONDT (9), although not designed to study the effect of ASA, did not reveal a difference in fellow eye involvement rate between those patients using vs those not using ASA. Two subsequent smaller retrospective studies proposed a substantial benefit from the use of ASA. Salomon et al (12) reviewed 52 patients for the development of fellow eye involvement, finding 8 of 16 (50%) without ASA use vs 5/28 (18%) with ASA ≥325 mg/day use, with follow-up up to 13 years. Although the differences were not statistically significant, the findings were felt to strongly suggest a benefit from ASA. The study has been criticized (41) for the unusually high fellow eye involvement rate in the very small sample of nontreated patients, inconsistent with other larger studies of fellow eye involvement. Kupersmith et al (10) reviewed the data from 100 patients with NAION, with 23/43 (53.5%) without ASA use developing fellow eye involvement vs 10/57 (17.5%) with ASA use, with follow-up up to 16 years. This study has been criticized for the same reasons. Two more recent meta-analyses have concluded that the evidence for ASA as an agent to reduce fellow eye involvement after NAION is either “weak” (42) or nonsupportive (43). The use of ASA in patients with NAION, to reduce either the risk of subsequent cardiovascular events or the development of fellow eye NAION, is not supported by the evidence. Although ASA has been shown to be effective for secondary prevention of cardiovascular events, the evidence for benefit in primary prevention, (in the population of NAION patients with no prior cardiovascular events), has been recently refuted. The role of thrombosis in NAION has not been established, and most data regarding the effect of ASA on fellow eye involvement do not support its use. Rebuttal: Robert A. Egan, MD I appreciate the scholarly article written by my colleague Dr. Arnold in coordination with mine. We have discussed a number of factors regarding second eye recurrence of AION and the paucity of data associated in favor and against those factors. I do not believe that the data that he has provided really differ from mine. The interpretation is slightly different. I will therefore not speak further on the issue of using aspirin to reduce the risk of second eye involvement, because the data is just too weak to prove either way and therefore not constructive. What I would like to address is the fear of intracerebral hemorrhage when using low dose aspirin. Many studies have been performed showing the positive effectiveness of aspirin in secondary prevention of ischemic stroke. However, there is also evidence that there is little if any benefit of low-dose aspirin in primary prevention of ischemic stroke in healthy subjects (44). Aspirin is not beneficial for primary prevention in healthy individuals except possibly in women above the age of 65 (45). These data were most significant for women above 65 over a 10-year period. However, with the addition of any cardiovascular risk factor that would affect a patient's life, aspirin reduces ischemic stroke risk and is recommended in the primary prevention of ischemic stroke (46). The risk of major hemorrhage does increase with aspirin usage even at low dose, but this is primarily related to gastrointestinal hemorrhage and not intracerebral hemorrhage and is dose related (47). Therefore, aspirin usage even at 81 mg a day should not be indiscriminate, but tailored to those patients with at least one vascular risk factor (48). Because many patients with AION suffer from at least one vascular risk factor, it makes perfect sense to prescribe low-dose aspirin for them even if the data of prevention of second eye involvement is weak but provocative. I would also propose an idea for a future double-blind, interventional, clinical study for the usage of dual antiplatelet therapy, which carries an increased risk of intracerebral hemorrhage if used long-term, vs aspirin and/or placebo for a 6–12 month period to see whether the rate of second eye involvement in AION can be reduced. The feasibility of performing this type of study would have to also be examined. Rebuttal: Anthony C. Arnold, MD It is reasonable to consider, as Dr. Egan does, that because ASA has proven effectiveness for the secondary prevention of cardiovascular events, including stroke, it may show a similar benefit for NAION in preventing second eye involvement. However, most strokes are thromboembolic events related to large vessel disease; as I indicated previously, the evidence that thrombosis plays a role in NAION is very weak: the available data suggest that this is a small vessel disease more likely related to hypoperfusion and a compartment syndrome than to thrombus. Although I have disagreed with Dr. Hayreh on several points regarding pathogenesis of NAION, I do agree with him on this point, described in his 2010 editorial (43) in Neuro-Ophthalmology: “Pathogenetically, NA-AION and cerebral stroke are not similar.” The use of ASA for prevention in NAION does not share the same rationale as for stroke. I would also like to place into perspective Dr. Egan's citation of the Beck study of 1997 (11). Although his quotation of the 2 year cumulative probability of fellow eye NAION involvement at 7% in ASA vs 15% in non-ASA subjects is accurate, the study actually concluded that although the short-term data suggested a benefit, the long-term (5 year) data of 17% vs 20% did not. Moreover, when Salomon and associates, in their paper supporting ASA use for prevention (12), quoted this study as “advocating administration of aspirin for prevention of a second event of nonarteritic anterior ischemic optic neuropathy (NAION),” Dr. Beck responded in print (41) that “This is a miscitation. On the contrary, we did not conclude, based on our data, that aspirin was beneficial.” In addition, as I previously noted, both the Salomon and the Kupersmith studies he cites as demonstrating effectiveness (10,12) showed very high non-ASA second eye involvement rates near 50%, unlike other studies of the natural history, making the non-ASA vs ASA comparison difficult to evaluate. In summary, although we tell our patients that NAION is “like a stroke of the optic nerve,” the analogy does not apply for pathogenesis or for prevention. The evidence does not support ASA use either for primary prevention of CNS or cardiac events or for prevention of second eye involvement. Conclusions: Andrew G. Lee, MD, and Gregory P. van Stavern, MD The efficacy of daily aspirin to prevent second eye involvement in NAION remains unproven. As noted by the authors, obtaining high quality evidence proving benefit (or lack thereof) is challenging given the rarity of the disease, the relatively low risk of second eye involvement and the need for long-term follow-up. It is also difficult to extrapolate from large, well-designed clinical trials assessing cerebral ischemia, because the mechanisms of ischemia may differ. It may be reasonable to recommend aspirin in patients with NAION and at least one known conventional vascular risk factor, or recommend continuing pre-existing treatment, but patients should be informed that although this treatment may reduce the risk of cerebral ischemic stroke, it is uncertain whether this lowers the risk of fellow eye NAION. It is possible that better understanding of the precise mechanism of NAION may provide better evidence for or against antiplatelet therapy.

Background: Posterior cortical atrophy (PCA) is a neurodegenerative syndrome that presents with higher-order visual dysfunction with relative sparing of memory and other cognitive domains, and it is most commonly associated with Alzheimer's disease pathology. There is a lack of data regarding the presentation of PCA to non-cognitive specialists. Therefore, we collected clinical data from neuro-ophthalmologists regarding the presentation of PCA to their practices and compared data to published cohorts and a published survey of cognitive specialists. Methods: Members of the North American Neuro-Ophthalmology Society Listserv (NANOSnet) were invited to complete an online, retrospective, chart-review data-entry survey regarding their patients with PCA, and REDCap was used for data collection. Results: Data for 38 patients were entered by 12 neuro-ophthalmologists. Patient mean age at presentation was 67.8 years, and 74% of patients were women. Difficulty reading was reported at presentation by 91% of patients, and poor performance on color vision, stereopsis, and visual field testing (performed reliably by 36/38 patients) were common findings. Most patients who were treated were treated with donepezil and/or memantine. Conclusions: Compared to published data from cognitive specialists, patients presenting to neuro-ophthalmology with PCA were more likely to be older and female and have a reading complaint. Reliable visual field testing was the norm with homonymous defects in the majority of patients. The neuro-ophthalmologist plays an important role in diagnosing PCA in older adults with unexplained visual signs and symptoms, and future studies of PCA should involve multiple specialists in order to advance our understanding of PCA and develop effective treatments.

Background: Susac syndrome (SS) classically presents with the clinical triad of retinal artery occlusion, sensorineural hearing loss, and encephalopathy and the neuroimaging triad of white matter lesions, deep gray matter lesions, and leptomeningeal disease. However, patients can present with an incomplete clinical or neuroimaging triads making diagnosis difficult in certain situations. A standard treatment paradigm also is lacking in this illness. It is important for neuro-ophthalmologists to recognize clinical and radiographic findings that are pathognomonic for this syndrome and have a basic understanding of the available treatment options. Evidence Acquisition: Review of medical literature. Results: A definite diagnosis of SS is made when the clinical triad or the neuroimaging triad is present. There are numerous reports of 2 other imaging findings in this condition: arteriolar wall hyperfluorescence (AWH) on fluorescein angiography in retinal arterioles remote from retinal ischemia and central callosal lesions on MRI. Both of these imaging findings are diagnostic of SS. Gass plaques in retinal arterioles are almost always seen in the acute phase of the illness but are not pathognomonic for SS. The most common medications used in this syndrome are corticosteroids and intravenous immunoglobulin. A number of other medications have been used including mycopheolate, rituximab, azathioprine, and cyclophosphamide. Conclusions: In the absence of the clinical triad or magnetic resonance imaging triad for SS, AWH remote from retinal vascular injury and central callosal lesions are confirmatory of the diagnosis because they have never been described in any other condition. The presence of Gass plaques in retinal arterioles should strongly suggest the diagnosis. Despite the lack of clinical trial data, patients with SS must be treated promptly and aggressively. In more fulminant cases, addition of mycophenolate mofetil or rituximab is required, followed by cyclophosphamide when disease is refractory to other medications.

Lisch nodules are melanocytic hamartomas that have been hypothesized to grow larger in the presence of sunlight. A 17-year-old boy with neurofibromatosis Type 1 and congenital ptosis in one eye presented and was found to have a distinct asymmetry of Lisch nodules between eyes with less under the ptotic lid. This case supports the theory that Lisch nodules form at least partially due to a direct trophic effect of sunlight.

OBJECTIVE:In population-based studies asymptomatic retinal emboli occur in .32%-2.9% of people. Retinal artery occlusion (RAO) may occur concurrently with cerebral stroke but the frequency is unknown. No study has examined how commonly retinal emboli occur in the acute stroke population. We aimed to assess the prevalence of retinal emboli and RAO at the time of carotid territory ischemic stroke.METHODS:Patients were enrolled prospectively after onset of symptoms consistent with the diagnosis of carotid territory ischemic stroke. Every participant underwent pharmacologic dilation of both pupils and bedside funduscopic examination. Emboli were classified as cholesterol, calcific, platelet/fibrin, or other and categorized by the side of occurrence. Stroke was classified as atheroembolic, cardioembolic, embolic stroke of undetermined source, lacunar, or other. Acute RAO was diagnosed by direct visualization of ischemic retinal whitening.RESULTS:Sixty-five patients were enrolled with a mean age of 59.2 years; 23 were female (35.4%). Eleven of 65 subjects (16.9%) had retinal emboli visible on funduscopy; all were cholesterol emboli except a single platelet/fibrin embolus in a patient with atheroembolic source. Six patients (9%) had acute RAO and no RAO was seen in the lacunar or undetermined source subgroups.CONCLUSIONS:Retinal emboli occurred more than 10 times more frequently in the acute stroke patient than in large population-based studies. RAOs also occurred concurrently with ischemic stroke. Although emboli were seen in patients with atheroembolic and cardioembolic sources, all patients with carotid disease had emboli in the ipsilateral eye. Future studies are required to determine if the presence of retinal emboli or RAO may help elucidate an etiology in patients suffering from embolic stroke of undetermined source.

Background: The ophthalmic findings of Susac syndrome (SS) consist of visual field defects related to branch retinal artery occlusion (BRAO), and fluorescein angiography (FA) reveals a unique staining pattern. To date, retinal arterial collateral development has been described only in a single patient. Given that the immunopathological process in SS induces retinal ischemia, it is conceivable that abnormal blood vessel development may occur in affected individuals. Methods: This is a retrospective observational study. The medical records including fundus photography and FA of all patients with SS were reviewed, and those with any type of retinal arterial collateral were identified. Results: A total of 11 patients were identified with retinal collaterals. Five were men. Age ranged from 20 to 50 years. Ten patients had arterio-arterial (A-A) collaterals and 1 had arterio-venous (A-V) collaterals, and all had collaterals remote from the optic disc. No collaterals were present at onset of illness and the first developed at 9 months. Conclusions: The literature reveals scant evidence for the association between BRAO and retinal arterial collaterals. Our findings indicate that retinal arterial collaterals in SS are usually A-A and not A-V and may be more common in this disorder than previously believed. Collaterals do not develop early in the disease, and there may be a predilection toward development in men. The chronic inflammatory state of SS may be the stimulus for the development of these arterial collaterals.

A 55-year-old woman noticed that her right pupil was oddly shaped, associated with a mild ache. Her afferent visual examination, ocular and eyelid motility, and fundi were normal. Her left pupil was round and reactive (figure 1). The right pupil was elongated (points at 11:00 and 5:00) and tonic (figure 2). There was no ocular hypertension or corneal edema. A year later, the pupil shape became triangular; evaluation revealed ocular hypertension without corneal edema, confirming the iridocorneal endothelial (ICE) syndrome. This case is an unusual presentation of a cat's eye Adie-like pupil as the harbinger for ICE syndrome.

Idiopathic intracranial hypertension (IIH) is a condition that is more common in women of childbearing age who are overweight. Headaches are a frequent complaint. A lumbar puncture (“spinal tap”) can show increased pressure in the spinal fluid around the brain. When the eyes are examined, swelling in the main nerve that connects the eye to the brain—the optic nerve—can often be seen. Permanent vision loss is the most feared complication of this disorder, so prompt evaluation and treatment are important.

Functional vision disorder (FVD) is a common problem seen in many neurologic and ophthalmologic practitioners' offices and may occur in isolation or in the presence of medical illness. This disorder presents with visual or oculomotor symptoms and manifests as vision loss in one or both eyes, visual field loss, double vision, oscillopsia, anisocoria, blepharospasm, or ptosis. Manual perimetry is the most effective method for determining functional visual loss, and the presence of a central scotoma in a functional visual field signifies that a neuropathophysiologic process is almost certainly present. The exact neuropathophysiologic mechanism of this disorder is unknown; however, information can be drawn from the small studies of FVD samples and studies examining neuropsychiatric factors in other conversion disorder semiologies. Psychological and psychiatric interventions can be useful in treating these patients.

Dear Editor, I read with interest the article titled Acute central retinal artery occlusion associated with livedoid vasculopathy: a variant of Sneddon's syndrome [1] and there may be a different diagnosis. Since a few cases of young patients have been identified with Susac syndrome with livedo, could this case represent a case of this disorder? Did the patient have an magnetic resonance imaging scan of the brain and were there any callosal lesions? What did the fluorescein angiogram of the left (the normal) eye show? This was not included in the paper. This author will state that central retinal artery occlusion is very rare in Susac syndrome but not impossible. Has this patient's hearing been checked?

Susac's syndrome is a rare autoimmune microangiopathy characterized by the clinical triad of encephalopathy, branch retinal artery occlusions, and sensorineural hearing loss. In many cases, the clinical triad is not fully present at the onset of symptoms. MRI studies often show characteristic punched out lesions of the central fibers of the corpus callosum, and leptomeningeal enhancement and deep gray matter lesions may also be seen. Here we present a case of Susac's syndrome in a middle aged man with the unique clinical finding of cauda equina syndrome and spinal MRI showing diffuse lumbosacral nerve root enhancement. Biopsy specimens of the brain, leptomeninges, and skin showed evidence of a pauci-immune endotheliopathy, consistent with pathology described in previous cases of Susac's syndrome. This case is important not only because it expands the clinical features of Susac's syndrome but also because it clarifies the mechanism of a disorder of the endothelium, an important target for many disorders of the nervous system.

Correspondence address: Mario Luiz Ribeiro Monteiro. Neuro-Ophthalmology Service. Escola de Me dicina da Universidade de Sao Paulo. Av. Angelica, 1.757 Conj. 61 Sao Paulo (SP) 01227-200 Brazil E-mail: mlrmonteiro@terra.com.br I read with interest the report of “Unilateral central retinal artery occlusion as the sole presenting sign of Susac syndrome in a young man: case report” by Apostolos-Pereira et al. Central retinal artery occlusion is very rare in Susac syndrome as evidenced by the paucity of reports in the clinical literature. The corpus callosum findings in this case are pathognomonic for the disease with the central callosal lesion and the 2 small spoke lesions in the posterior callosum. However, the fundus appearance is somewhat odd with the significant platelet-like embolic material in the arterioles. These are not Gass plaques as has been described previously. Did they disappear after his initial presentation? There are also characteristic fluorescein angiographic findings described previously. Was the typical autofluorescense pattern located remotely from the retinal artery occlusion? I am particularly interested in learning if the right eye showed this pattern prior to infarction; if so, can this be published? Were anti-en dothelial cell antibodies sent?