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Ethambutol is an antimicrobial agent used frequently to treat tuberculosis. The most commonly recognized toxic effect of ethambutol is optic neuropathy, which generally is considered uncommon and reversible in medical literature. We describe a 43-year-old man who developed signs and symptoms of bilateral optic neuropathy during treatment with ethambutol. This case and a review of the literature show the severe and unpredictable nature of ethambutol toxicity and its potential for irreversible vision loss despite careful ophthalmologic monitoring. [ABSTRACT FROM AUTHOR]

Background: Occurrence of comitant ocular deviation in myasthenia gravis (MG) is not well described., Methods: A retrospective analysis of patients with ocular or generalized MG evaluated at a neuro-ophthalmology clinic for a 6-year period. Comitant ocular deviation was defined as magnitude of deviations in all planes varying by <20% from the measurement in the primary position., Results: Among the 120 patients included, 89 patients had ocular and 31 patients generalized MG. At the initial strabismus testing, comitant ocular deviation was present in 27 (22.5%) patients. Among the 16 patients who had a follow-up, ocular deviation remained comitant in 6 patients and converted to incomitant or no ocular deviation in 10 patients. An additional 7 patients demonstrated comitant ocular deviation at follow-up. Brain MRI was performed in 18 patients with comitant ocular deviation, and none showed abnormalities in the brainstem or cerebellum., Conclusion: Comitant ocular deviation can be an ocular manifestation of MG. Its presence does not necessarily indicate a central etiology in patients with MG neither excluding a MG diagnosis., Competing Interests: The authors report no conflicts of interest., (Copyright © 2020 by North American Neuro-Ophthalmology Society.)

Angioinvasive aspergillosis is an aggressive fungal infection that is potentially life threatening without prompt treatment. Optic nerve involvement of Aspergillus can mimic optic neuritis commonly seen in demyelinating and other inflammatory conditions. Treatment of Aspergillus infection with steroids may worsen the clinical course. We describe a unique case of disseminated central nervous system aspergillosis, initially presenting as an optic neuropathy, with subsequent stroke in multiple vascular territories.

A 38-year-old woman presented with chronic left retro-orbital pain and photophobia. Palpation of the left occipital prominence revealed tenderness in the area of the greater occipital nerve and reproduced the eye pain. The diagnosis of cervicogenic headache was confirmed by symptom resolution following left greater occipital nerve blockade. The functional association between the greater occipital nerve and the trigeminal nerve provides a potential mechanism for this case of cervicogenic eye pain., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Idiopathic intracranial hypertension (IIH) is most often diagnosed in young obese females of childbearing years. The diagnosis is made based on the modified Dandy criteria and the exclusion of alternate causes of raised intracranial pressure., Results: The focus of this review is to provide an overview of the diagnosis and treatment options for patients with IIH. There are long-term consequences for patients experiencing IIH, with visual loss being the most serious., Conclusion: We conclude that the diagnosis of IIH is not usually difficult. An ophthalmologic examination is essential in patients with IIH to monitor visual function. A neurologist or neurosurgeon may be needed at some point for medical and/or surgical intervention., (© 2014 American Headache Society.)

We conducted a masked, crossover, therapeutic trial of gabapentin (1,200mg/day) versus memantine (40 mg/day) for acquired nystagmus in 10 patients (aged 28-61 years; 7 female; 3 multiple sclerosis [MS]; 6 post-stroke; 1 post-traumatic). Nystagmus was pendular in 6 patients (4 oculopalatal tremor; 2 MS) and jerk upbeat, hemi-seesaw, torsional, or upbeat-diagonal in each of the others. For the group, both drugs reduced median eye speed (p < 0.001), gabapentin by 32.8% and memantine by 27.8%, and improved visual acuity (p < 0.05). Each patient improved with 1 or both drugs. Side effects included unsteadiness with gabapentin and lethargy with memantine. Both drugs should be considered as treatment for acquired forms of nystagmus.

A 52-year-old man developed transient, migratory polyarthralgias in the presence of hearing loss. He then developed persistent leukocytosis and thrombocytosis. His initial transient, bilateral visual obscurations happened in context with bilateral disk edema and an enlarged blind spot. Visual symptoms progressed to vision loss and multiple branch retinal artery occlusions. It was not until later in the disease progression that gastrointestinal symptoms occurred. Electron microscopy of duodenal biopsies confirmed a diagnosis of Whipple disease.

Ptosis is a common clinical finding. The many causes of ptosis include involutional (aging), myopathic, neuropathic, congenital, infectious, tumorous, traumatic, and inflammatory processes. This article reviews recent literature on some causes of ptosis and other lid conditions.

A 59-year-old woman noted intermittent ptosis, diplopia, dysphagia, and proximal muscle weakness for several years. She had a strong family history of myasthenia gravis. Chest computed tomography and sternotomy revealed a micronodular spindle cell thymoma. Electromyography and antibody testing was negative for myasthenia gravis. Genetic testing confirmed a diagnosis of oculopharyngeal muscular dystrophy.

Purpose: To measure the pressure in the temporal and central aspects of the chiasm simultaneously during compression of the optic chiasm from below with an expanding simulated tumor., Design: Experimental study., Methods: Craniotomies were performed on 5 unfixed cadaveric specimens ranging in age from 49 to 89 years, and the optic chiasm was exposed. After a pediatric gauge Foley catheter was inserted into the sellar region, the temporal side of the chiasm (temporal aspect uncrossed fibers) was impaled with a 30-gauge needle connected to a pressure transducer. In like fashion, the central portion of the chiasm (crossed fibers) was impaled with another 30-gauge needle connected to a pressure transducer on a separate channel. The Foley catheter was inflated for a period of 30 seconds to 1 minute and the pressure in each channel continuously monitored. Multiple trials were performed on each of the 5 specimens., Main Outcome Measure: Pressure change between the temporal and nasal aspects of the optic chiasm., Results: In all cases in which intrachiasmal pressure could be measured, higher pressures were always generated in the central aspect of the chiasm than in the temporal aspect of the chiasm. In cadaver 1, the mean central pressure was 19.75 mmHg, whereas the mean temporal pressure was 6 mmHg. In cadaver 5, the mean central pressure was 4 mmHg, whereas the mean temporal pressure was zero. Donors 70 and older demonstrated abnormally thin and frail chiasms that were unable to support a sustained pressure increase during simulated tumor expansion., Conclusions: During deformation of the optic chiasm from below by a radially expanding mass analogous to a pituitary tumor, the central aspect of the optic chiasm consistently manifests a higher pressure than the temporal aspect. It is hypothesized that the peculiar geometry of the optic chiasm renders the crossing nasal fibers more prone to a deformation stress exerted from below. Nonuniform pressure generation between the central and temporal aspects of the chiasm results in a greater effective stress on the crossing fibers of the chiasm and may be responsible for the clinical phenomenon of bitemporal hemianopsia.

Objective: Ocular symptoms and signs often herald hemispheric neurological events associated with extracranial cerebrovascular disease. However, the presence of a Hollenhorst plaque (HP) or retinal artery occlusion (RAO) and the risk of stroke is unclear. The purpose of this study was to review the outcomes of all patients who presented with a HP or RAO at a single institution., Methods: Between 2000 and 2005, the management and outcome of 130 consecutive patients with a diagnosis of HP, central RAO, or branch RAO (ICD-9 codes 362.30 to 362.33) were reviewed. Patients with transient monocular visual loss (amaurosis fugax), retinal venous occlusion, and other ocular pathologies were excluded. Electronic and hardcopy medical records were reviewed for demographic data, clinical variables, radiological, and noninvasive vascular lab testing. Duplex and magnetic resonance angiography (MRA) of the carotid arteries were reviewed to confirm the presence of a lesion and quantify the degree of stenosis., Results: During the study interval, 70 males and 60 females, with a mean age of 68 +/- 16 (+/-SD) years underwent ophthalmologic evaluation. Symptoms were present in 61% of patients and included eye pain, blurred vision, or atypical visual symptoms, while 39% were asymptomatic. Atherosclerotic risk factors in this population included the presence of hypertension (73%), diabetes (33%), hyperlipidemia (75%), and tobacco use (38%). A majority of patients underwent carotid interrogation via Duplex imaging (68%). Carotid bifurcation stenoses ipsilateral to the ocular findings were <30% in 68% of the patients, between 30 and 60% in 22% and >60% in only 8% of patients. Six patients with lesions greater than 60% went on to have either a carotid endarterectomy or carotid stenting. Follow-up data on this group ranged from 1 to 49 months (median, 22 months), with no stroke or transient ischemic attack identified. There were five deaths during follow-up; none related to stroke. Serial carotid Duplex examinations failed to identify progression of carotid stenoses in this group of patients. Overall survival was 94% at 36 months for this cohort., Conclusion: The presence of a HP or RAO is associated with a low prevalence of extracranial cerebrovascular disease that requires intervention. Furthermore, in contradistinction to amaurosis fugax, these ocular findings are not associated with a high risk for hemispheric neurological events.

Purpose: Cerebral venous hypertension with optic nerve edema has been reported in patients with peripheral arteriovenous hemodialysis shunts. This study aimed to estimate the prevalence of optic nerve edema in patients with peripheral arteriovenous accesses and to evaluate the value of ophthalmic examination and surveillance in this study population., Design: Cross-sectional observation case series., Participants: Forty-four patients with peripheral arteriovenous shunts for hemodialysis., Methods: A cross-sectional observation was done of all patients with peripheral arteriovenous shunts presenting to our outpatient hemodialysis unit on 2 consecutive days. Using indirect ophthalmoscopy, the presence or absence of optic nerve edema was recorded. Patients also were asked to record any symptoms suggestive of intracranial hypertension and/or papilledema such as headache, decreased visual acuity, or an abnormal visual phenomenon. The 95% confidence interval (CI) was calculated to estimate the prevalence of optic nerve edema in patients with peripheral arteriovenous accesses. A literature search also was conducted to obtain prior reports of optic nerve edema and ophthalmic complications in patients with peripheral arteriovenous accesses., Main Outcome Measures: Presence or absence of optic nerve edema., Results: Among our series of 44 patients with peripheral arteriovenous shunts for hemodialysis, no case of optic nerve edema was observed and no patient reported any headache, decrease in vision, or visual phenomenon. The 95% CI for the estimated prevalence of optic nerve edema was 0% to 8.0%. A literature review revealed 7 reports of symptomatic ophthalmic complications in patients with peripheral arteriovenous accesses., Conclusions: Although cases of papilledema in patients with peripheral arteriovenous shunts have been reported in the literature, the occurrence appears to be low, and routine ophthalmic surveillance is probably unnecessary in asymptomatic patients.

We report a patient with dysthyroid optic neuropathy refractory to steroids and orbital decompression treated with rapamycin, a fibroblast and T cell inhibitor. Symptoms, visual acuity, color plate testing, and visual fields improved. Aside from hypercholesterolemia, no complication related to this therapy was observed. By addressing the pathogenesis of thyroid eye disease, rapamycin may represent an alternative when standard treatments fail. Further investigation of rapamycin for treatment of dysthyroid orbitopathy is warranted.

We present a case in which mfERG and OCT helped to make a diagnosis of an old BRAO in the setting of compound heterozygous MTHFR genotype. A 44-year-old woman presented for evaluation of a 10 month history of persistently cloudy vision OS. She had been worked up previously for MS versus BRAO, and she was on coumadin, folate, and multivitamin at the time of presentation. The patient has a fraternal twin sister who was diagnosed with MS. Dilated fundus examination OS showed subtle inferior optic atrophy with slight narrowing of the inferotemporal retinal artery, and HVF test revealed a superonasal depression OS. mfERG also showed superonasal depression OS. Retinal origin of the chief complaint was further confirmed by OCT, which showed thinning of the NFL in the corresponding region of the retina OS. Coagulopathy evaluation revealed C677T/A1298C compound heterozygous genotype for MTHFR, and plasma homocysteine level after 6 months of folate and multivitamin supplementation was 10 microM (reference range 4-10 microM). The patient was diagnosed with BRAO and maintained on coumadin therapy.

Purpose: To describe an unusual case of Churg-Strauss syndrome (CSS) that presented with a conjunctival nodule and was successfully treated with oral corticosteroids., Methods: Case report., Results: A 30-year-old woman with a history of adult-onset asthma, seasonal allergies, and a lung mass presented with a nodular elevation of the conjunctiva. Excisional biopsy demonstrated necrotizing eosinophilic granulomas. Systemic evaluation revealed peripheral eosinophilia and elevated IgE, consistent with Churg-Strauss syndrome. The patient's symptoms and eosinophilia resolved after an increase in the dose of oral corticosteroids., Conclusions: This case describes a unique presentation of conjunctival involvement in CSS that differs from prior case reports by having a small, well-demarcated nodule and lacking signs of active inflammation.

There are many neurological manifestations of vitamin B(12) deficiency. Optic neuropathy is a rare, but important, manifestation of vitamin B(12) deficiency that should be suspected in patients with risk factors for malnutrition. We present a case of a 68-year-old male who presented with bilateral decreased central vision for months and was found to have a low vitamin B(12) level. After a few months, his vision improved with parenteral vitamin B(12) supplementation. Vitamin B(12) optic neuropathy is a reversible, treatable cause of vision loss and may be a harbinger for other manifestations of the disease.

Purpose: To report on the prevalence of psychiatric disease and psychosocial stress in children with nonorganic visual loss., Materials and Methods: Case series of 71 consecutive pediatric patients with a variety of nonorganic visual signs and symptoms. Chart review of ophthalmologic findings and details of medical and social history with main outcome measures of prevalence of psychiatric disease and psychosocial stress., Results: Psychological/psychiatric disturbances in the form of anxiety, depression, and attention deficit hyperactivity disorder had been previously diagnosed in 19 (26.7%) patients. We had a very high index of suspicion of psychiatric illness in another four patients. Furthermore, we uncovered significant home and school stress in 22 (31%) patients. Sixteen (22.5%) patients wanted glasses and in 10 (14.1%) patients no cause for the behavior could be determined. Of those patients who wanted glasses, girls outnumbered boys 3:1., Conclusions: An underlying psychiatric or psychosocial disturbance should be ruled out in children who present with nonorganic visual loss.

The purpose of this article is to report the methods and results of the surgical quality assurance program associated with the Ischemic Optic Neuropathy Decompression Trial (IONDT). A surgical quality assurance committee developed and implemented a quality assurance program for a randomized clinical trial requiring surgical intervention. A surgical technique questionnaire was administered at two times during the study course, and maintenance of surgeon certification required submission and approval of a masked videotape of an optic nerve sheath decompression surgery by each study surgeon. Surgical quality was assessed through completion of surgical report forms and standardized, masked review of operative notes. Rates of compliance and intra- and interreviewer agreement were assessed for each aspect of the program. Twenty-five of 32 surgeons (81%) successfully completed and maintained certification. Item agreement varied from 21-92% among reviewers of satisfactory videotapes and 22-89% on unsatisfactory videotapes. Intrarater agreement for videotape acceptability was 11 of 13 (85%), and for specific surgical steps, 147 of 182 (81%). Operative notes were submitted for 123 of 125 (98%) patients receiving surgery. Interrater agreement on individual items ranged from 73-100%. Classification of individual items was identical on first and second review for 1285 of 1344 (95.6%) items. Overall agreement for individual reviewers was 93.8-97.8%. We conclude that use of a small peer review committee, which developed and oversaw a quality assurance program, allowed for consistent certification and monitoring of surgical performance. This in turn increased the credibility of the IONDT results, which demonstrated no difference in outcome between operated and unoperated groups of patients.

Purpose: To investigate therapeutic effects of oral gabapentin therapy on superior oblique myokymia., Design: Observational case series with measurement of visual acuity and eye movements before, during, and after therapy., Methods: Two adult patients with superior oblique myokymia, refractory to other therapies, were treated with gabapentin orally after informed consent was obtained. Eye movements were measured using the magnetic search coil technique., Results: Superior oblique myokymia completely resolved after starting gabapentin., Conclusion: Gabapentin may be an effective treatment for superior oblique myokymia; a double-blind study seems justified.

Purpose: To describe the usefulness of chest computerized tomography (CT) in the evaluation of uveitis in elderly women and the clinical characteristics of patients with an abnormal chest CT scan., Design: Prospective noncomparative case series., Methods: We evaluated 30 elderly women, aged 61-83 years, with chronic iritis, vitritis, or choroiditis and with no definitive cause for their uveitis. All patients underwent a battery of diagnostic laboratory studies and chest CT., Results: The diagnostic examination in most patients included serum angiotensin converting enzyme level, serum lysozyme, rapid plasma reagin level, fluorescent treponemal antibody-absorption test, purified protein derivative skin test, and chest x-rays. Chest CT performed on all patients showed parenchymal, mediastinal, and/or hilar adenopathy in 17 patients (57%). Histopathologic confirmation of sarcoidosis with noncaseating granulomas in the biopsy specimens was obtained in 14 patients: eight by mediastinoscopy, two by bronchoscopy, two by conjunctival biopsy, one by nasal biopsy, and one by vitreous biopsy., Conclusions: Chest CT can be useful in elderly female patients with chronic uveitis for identifying mediastinal lymphadenopathy and other lesions suggestive of sarcoidosis, as well as to help guide tissue confirmation and to rule out other diagnoses including lymphoma.

Objective: To present an unusual case of pseudotumor cerebri with increased intracranial pressure isolated to the cerebral ventricles resulting from a Chiari I malformation., Materials and Methods: The patient received a complete ophthalmologic examination on initial presentation and subsequent visits, including visual acuity, pupillary examination, intraocular pressures, dilated fundus examination with assessment of degree of papilledema, and visual field testing. Intracranial pressure was measured by lumbar puncture and subsequently by intracranial pressure bolt monitoring. Magnetic resonance imaging (MRI) was used to diagnose the Chiari I malformation., Results: The patient initially presented with bitemporal headaches, elevated opening pressure on lumbar puncture, and mild papilledema with a normal MRI. After lumboperitoneal shunt placement and several revisions, the patient presented with decreased vision OD secondary to Terson syndrome and worsening papilledema. Subsequent evaluation revealed normal lumbar opening pressures and a Chiari I malformation. She underwent ventriculoperitoneal shunt placement with resolution of her symptoms., Conclusions: Tonsillar herniation is a well-documented complication of lumboperitoneal shunt revision. Obstruction of cerebrospinal flow through the foramina of Magendie and Luschka can result in increased intracranial pressure isolated to the cerebral ventricles. In a patient with signs and symptoms of increased intracranial pressure but normal lumbar opening pressure, a Chiari I malformation should be suspected, particularly with a history of multiple lumboperitoneal shunt revisions.

Purpose: To determine whether a relationship exists between increased intracranial pressure and the presence of idiopathic choroidal folds., Methods: A prospective study in which 12 consecutive patients presenting with choroidal folds were evaluated by imaging studies (ultrasonography, magnetic resonance imaging, and/or computed tomography) to rule out known causes of choroidal folds, such as orbital disease, choroidal tumor, posterior scleritis, hypotony, and choroidal neovascular membrane. A lumbar puncture was performed on each of these patients, and measurement of opening pressure of cerebrospinal fluid was obtained., Results: Twelve patients with choroidal folds included nine men and three women. Six patients (50%) presented with papilledema in the eye with choroidal folds. The other six patients (50%) presented with only choroidal folds. In this study, 10 (83%) of 12 patients had an opening pressure greater than 230 mm H(2)O. In patients presenting with only choroidal folds, five (83%) of six patients had an opening pressure greater than 230 mm H(2)O, with an average opening pressure of 290 mm H(2)O., Conclusion: Depending on the timing of the evaluation, papilledema may or may not be present, and only choroidal folds may be seen as a reflection of increased intracranial pressure. We believe that increased intracranial pressure from any source (that is, pseudotumor cerebri, sinus thrombosis, or intracranial mass) can present with only choroidal folds; therefore, these patients should have an appropriate work-up that should probably include a lumbar puncture before the title of "idiopathic" is given to their finding.

Arteriovenous malformations (AVMs) are anomalous communications between arterial and venous systems without interposed capillaries. These lesions are rarely entirely intraorbital. A case of an arteriovenous communication between branches of the internal and external carotid arterial circulations and the ophthalmic veins located within the orbit is reported. Treatment with embolization resulted in a branch retinal artery occlusion. Attempted direct arterial occlusion of a dural-based fistula of the eye is a risky procedure. If embolized, AVMs should probably be approached from the venous side, if at all.

Anti-Ri antibodies most often occur in patients with breast cancer and typically are associated with the paraneoplastic syndrome of opsoclonus-myoclonus-ataxia. This study reports a patient with diplopia and ophthalmoplegia. She had anti-Ri antibodies, and despite an exhaustive search for malignancy at presentation, breast cancer was not detected for six months.

Objective: To examine the relationship between vertical anisometropic spectacle correction and vertical fusional amplitudes in patients., Design: Comparative observational case series., Participants: Twenty-one patients exposed to greater than 0.5 diopters of vertical anisometropic spectacle correction were compared with 46 patients not exposed to anisometropic correction., Methods: Vertical fusional amplitudes were recorded in all patients using a prism bar., Main Outcome Measures: Vertical fusional amplitudes and vertical anisometropia., Results: In patients exposed to greater than 0.5 diopters of vertical anisometropic spectacle correction, vertical fusional amplitudes measured 5.2+/-1.4 prism diopters. Patients not exposed to anisometropic correction had vertical fusional amplitudes of 2.7+/-1.2 prism diopters (P < 0.0001)., Conclusion: Patients with vertical anisometropic correction have increased vertical fusional amplitudes. This finding is relevant when evaluating patients with ocular motility disorders, especially with regard to distinguishing acquired versus longstanding deviations.

Purpose: To determine orbital tissue tension and orbital compartment compliance in patients with and without thyroid-associated orbitopathy (TAO)., Design: Prospective case series., Participants: Orbits of patients with TAO (18 orbits) and control patients without TAO (35 orbits) were studied., Methods: An orbital manometer was designed to directly measure orbital tissue tension in patients undergoing ocular or orbital surgery., Main Outcome Measures: Tissue tension was recorded before, during, and for 5 minutes after a 5-ml retrobulbar injection of anesthetic. Orbital compliance was calculated as change in volume divided by change in tissue tension., Results: Resting orbital tissue tension was 4.4 +/- 2.2 mmHg (mean +/- SD) in normal orbits and 9.7 +/- 4.8 mmHg in orbits of TAO patients (P = 0.0005) Following retrobulbar injection, orbital tissue tension rose to 12.0 +/- 3.6 mmHg (P = 0.0000000000000006 compared with baseline) in the control group and to 36.3 +/- 15.2 mmHg in the TAO group (P = 0.0000007 compared with baseline, and P = 0.000008 TAO group versus control group). Orbital compartment compliance was 0.80 +/- 0.50 ml/mmHg in the control group and 0.27 +/- 0.21 ml/mmHg in the TAO group (P = 0.00001). Resting orbital tissue tension in 8 TAO orbits with compressive optic neuropathy was 12.4 +/- 4.9 mmHg, and was 7.8 +/- 3.5 mmHg in 10 orbits of TAO patients without compressive optic neuropathy (P < 0.05). No adverse events occurred., Conclusions: Retrobulbar injection causes consistent measurable changes in orbital tissue tension. Orbital manometry safely demonstrated higher orbital tissue tension and lower orbital compartment compliance in the orbits of TAO patients versus those of normal subjects. Resting orbital tissue tension was higher in the orbits of TAO patients with compressive optic neuropathy than in those orbits without. Compressive optic neuropathy may partially result from an orbital compartment syndrome in some patients with TAO. Directly assessing orbital dynamics in vivo may prove useful as an adjunct in the clinical evaluation of patients with TAO and other orbital disorders.

Purpose: To determine orbital tissue tension and orbital compartment compliance in normal patients., Methods: An orbital manometer was designed to directly measure orbital tissue tension before, during, and after a 5-ml retrobulbar injection of anesthetic in patients undergoing ocular surgery. Tissue tension was recorded for 5 minutes after the injection. Orbital compliance was calculated as change in volume divided by change in pressure. Data were collected from 18 normal orbits., Results: Resting orbital tissue tension was 4.0 +/- 1.5 mmHg (mean +/- standard deviation). After retrobulbar injection, orbital tissue tension rose to 11.6 +/- 2.6 mmHg (p = 0.00000000009 compared with baseline). After 5 minutes, tissue tension declined to 6.6 +/- 1.9 mmHg (p = 0.00000001 compared with preinjection and p = 0.00002 compared with postinjection). Orbital compartment compliance was 0.74 +/- 0.31 ml/mmHg. No adverse events occurred., Conclusions: The authors' orbital manometer safely determined orbital tissue tension and orbital compartment compliance in normal orbits. Retrobulbar injection causes consistent measurable changes in orbital tissue tension. Directly assessing orbital dynamics in vivo may prove useful both as an adjunct in the clinical evaluation of patients with disorders resulting in an orbital compartment syndrome as well as in assessing the risk of retrobulbar injection in orbits at greater risk for complications from this procedure.

There are many causes of sudden painless visual loss in older adults. This article reviews the causes that are based on disturbances of the optic nerve and disorders of the circulatory system of the eye. Clinical clues to the recognition of these disorders and treatment (if available) are reviewed.

Purpose: To describe the corneal findings in a variant of Gaucher disease., Methods: Case report. In an 18-year-old man, ophthalmic and general clinical evaluation, and enzymatic and molecular genetics studies were performed., Results: Diffuse, well-defined, small, linear, or dotlike corneal opacities were observed through, out the posterior two thirds of the corneal stroma in both eyes. The patient had calcific valvular heart disease. Enzymatic and ultrastructural studies were consistent with Gaucher disease. Analysis of the glucocerebrosidase gene disclosed homozygosity for a D409H mutation., Conclusion: Corneal opacities are a distinguishing ocular feature of the variant of Gaucher disease associated with the D409H mutation and with calcific cardiac disease.

Purpose: To report the usefulness of chest computed tomography and mediastinoscopy in diagnosing sarcoidosis in elderly patients with uveitis., Methods: Case reports. Two Caucasian women, aged 73 and 70 years, underwent evaluations for uveitis, which included chest computed tomography and mediastinoscopy., Results: A chest computed tomographic scan of each woman disclosed mediastinal lymphadenopathy and warranted mediastinal lymph node biopsy by mediastinoscopy. In both patients, histopathologic and microbiologic studies demonstrated sterile noncaseating granulomas consistent with the diagnosis of sarcoidosis., Conclusions: The diagnosis of sarcoid-associated uveitis in the elderly may be facilitated by chest computed tomography, which may be more sensitive than conventional chest roentgenography. Laboratory studies of biopsied mediastinal nodes obtained by mediastinoscopy can confirm the diagnosis.

A 17-year-old woman presented with a history of 1-week of headache and 3 days of horizontal diplopia. Examination revealed 20/20 vision in both eyes, no papilledema, and an abduction deficit in her left eye. Lumbar puncture revealed an opening pressure of 440 mm H2O. After treatment with acetazolamide, the headache and abduction deficit resolved. Papilledema never developed. This is a unique case of pseudotumor cerebri sine papilledema with a unilateral abduction deficit. We suggest that young women with headache and unilateral abduction deficits may be unrecognized cases of pseudotumor cerebri.

Purpose: We report a case of ischaemic optic neuropathy which occurred after prolonged spine surgery in the prone position in an obese, diabetic patient., Clinical Features: The patient was a 44-yr-old, 123 kg, 183 cm man for decompressive laminectomy and instrumented fusion of the lumbar spine. Anaesthesia was induced with thiopentone, fentanyl and succinylcholine and maintained with nitrous oxide, oxygen, isoflurane and a fentanyl infusion. He was positioned prone on the Relton-Hall frame and had an uneventful intraoperative course. Estimated blood loss was 3,000 ml. He was taken to the surgical intensive care unit (SICU) and the trachea was extubated 3.5 hr later. He had no pulmonary or haemodynamic problems and went to a regular nursing floor in the morning. He was discharged home on postoperative day #5. He telephoned his surgeon on postoperative day #7 to say that his vision had been blurry since surgery. His visual acuity was decreased, and on examination, he had a bilateral papillary defect, optic swelling and a splinter haemorrhage in the right eye. Magnetic resonance imaging (MRI) scan of the head and orbits detected no other abnormality. Based on this examination, he was felt to have bilateral ischaemic optic neuropathy and treated conservatively. By postoperative day #47, his visual acuity was greatly improved and near normal. Careful review of possible contributing factors suggests that the cause of the ischaemic optic neuropathy was venous engorgement., Conclusion: This patient developed ischaemic optic neuropathy from a prolonged interval in the prone position of the Relton-Hall frame, which may be related to venous engorgement.

Purpose: To bring attention to the implications of thrombocytosis in giant cell arteritis., Method: Case report. Platelet counts were measured before and after corticosteroid therapy in a patient with biopsy-proven giant cell arteritis., Result: Platelet counts were increased before corticosteroid therapy was begun and returned to normal levels after corticosteroid therapy was instituted., Conclusion: Platelet counts in a patient with giant cell arteritis may have diagnostic, therapeutic, and prognostic value.

We report a case of primary optic pathway sarcoidosis in a 38-year-old white man. The disorder was limited to the optic nerves and was resistant to corticosteroids.

Purpose: Hysterical and malingering patients can manifest visual field defects on perimetry (visual field testing), including defects suggestive of true visual pathway pathology. It has been shown that control subjects can easily imitate some pathologic defects with automated, computed perimetry. The authors sought to determine whether subjects could imitate the same pathologic defect with manual and automated perimetry., Method: Six subjects posed as patients with neurologic problems. They had manual perimetry with both an experienced and inexperienced technician followed by automated perimetry. They were later interviewed about the methods of the technicians and the difficulty of the exercise., Results: Four of six subjects easily imitated the assigned defects with both technicians on manual perimetry and with automated perimetry. These included quadrantic, altitudinal, hemianopic, and enlarged blind-spot defects. Two subjects who were assigned cecocentral and paracentral scotomas instead produced enlarged blind spots by manual perimetry and defects suggestive of chiasmal pathology by automated perimetry. Paradoxically, some subjects found that experienced technicians were easier to fool than inexperienced technicians because of the systematic way in which experienced technicians defined defects., Conclusions: With minimal coaching, some subjects can imitate visual fields with enlarged blind spots, quadrantic, hemianopic, and altitudinal defects with ease and reproducibility by both automated and manual perimetry. Cecocentral and paracentral scotomas are harder to imitate but may be mistaken as representing chiasmal pathology. Paradoxically, experienced technicians may not be better at detecting hysterical or malingering individuals.