- Email: [email protected]
Functional Visual Loss in Idiopathic Intracranial Hypertension
Functional Visual Loss in Idiopathic Intracranial Hypertension Joshua J. Ney, MD,1 Nicholas J. Volpe, MD,1,2 Grant T. Liu, MD,1 Laura J. Balcer, MD, MSCE,1 Mark L. Moster, MD,2 Steven L. Galetta, MD1 Objective: To identify and describe patients with idiopathic intracranial hypertension (IIH) with concurrent functional visual loss (FVL). Design: Observational, retrospective case series. Participants: Seventeen patients with IIH and FVL. Methods: Clinical features were collected retrospectively. Data from 281 cases of IIH were analyzed for concurrence of FVL. Main Outcome Measures: Occurrence of FVL diagnosed at presentation or on subsequent follow-up. Results: Seventeen patients had FVL and IIH. Of the 17 patients with FVL and IIH, 11 (65%) had FVL on presentation, with the remaining 6 patients developing FVL after initial presentation. Two patients in this cohort had documented recurrence of their IIH. There were several common patterns of FVL. All 17 patients had functional visual fields, with 82% having tubular fields and 71% exhibiting nonphysiologic constriction on perimetry testing. Seventy-six percent of patients had nerve/field mismatch showing no atrophic disc changes. Eighty-eight percent of patients had significant psychiatric, psychosocial, or other medical comorbidities. The majority of patients were managed surgically at some point in their clinical history, with 53% having nerve decompression, shunt, or both. Three patients had optic nerve sheath fenestrations after the diagnosis of FVL. Conclusions: Results suggest a high prevalence of FVL in IIH with a potential association with psychiatric illness and psychosocial stressors requiring careful consideration before surgical intervention. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Ophthalmology 2009;116:1808 –1813 © 2009 by the American Academy of Ophthalmology.
Functional or nonorganic visual loss refers to loss of vision that cannot be explained by pathology of the eye or visual pathway. Recent reviews have cited a prevalence of functional visual loss (FVL) ranging from 5% to 12% of patients who present with visual loss to a neuro-ophthalmologist.1 Concomitant organic disease has been reported in up to 53% of patients with FVL.2 Such observations reinforce the necessity for practitioners’ persistent vigilance in identifying organic disease in patients with FVL, recognizing the potential association between certain diseases and FVL. Our goal was to describe an association observed in patients diagnosed with idiopathic intracranial hypertension (IIH) with concomitant FVL. Idiopathic intracranial hypertension has an incidence reported to be as high as 20 per 100 000 people and typically occurs in obese women of childbearing age.3 The natural history of the disease is variable, with most cases protracted over months to years. Visual disturbances are nearly universal, ranging from visual blurring or transient visual obscurations to visual field loss.4,5 The defects are usually asymptomatic and include enlargement of the natural blind spot, arcuate defects, or generalized constriction of the visual field. These defects often resolve after optic nerve swelling resolution. Despite the relatively benign disease progression, clinicians need to be vigilant in screening for visual loss that would suggest a more fulminant course,
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© 2009 by the American Academy of Ophthalmology Published by Elsevier Inc.
because up to 5% to 30% will have permanent significant visual field loss, defined as progressive deterioration of visual fields.4 Functional visual loss superimposed on IIH would also complicate decision-making regarding surgical intervention. Although there have been studies evaluating the concurrence of certain functional patterns and organic disease, the relationship of FVL and IIH has not been extensively described. The purpose of this study is to characterize the patterns of FVL in IIH and identify any predisposing characteristics, such as psychiatric illness, that may put this patient population at risk for developing FVL.
Materials and Methods We performed a retrospective chart review of 281 patients with the diagnosis of IIH evaluated at the University of Pennsylvania Hospitals and Albert Einstein Medical Center, Departments of Neurology and Ophthalmology, from January 1995 to December 2007. Institutional review board approval was obtained, and the study was conducted in accordance with the Health Insurance Portability and Accountability Act guidelines. Inclusion criteria included (1) patients at least 18 years of age, evaluated and followed by a neuro-ophthalmologist, and (2) a diagnosis of IIH fulfilling the Modified Dandy Criteria6 or made on the ISSN 0161-6420/09/$–see front matter doi:10.1016/j.ophtha.2009.03.056
Ney et al 䡠 FVL in IIH clinical impression of the neuro-ophthalmologist. Patients were excluded from this study if adequate follow-up data were unavailable. We generated a patient list with International Statistical Classification of Diseases Ninth Revision codes 348.2 and 377.01 for “benign intracranial hypertension” and “papilledema associated with increased intracranial pressure,” respectively. This list was supplemented with the personal databases of patients with IIH seen by NJV, GTL, LJB, MLM, and SLG. We compiled a digital archive of available Microsoft Word (Microsoft Corp, Redmond, WA) dictation notes from all patient visits during the specified time period. The archive was searched for each name on the master IIH list. Patients for whom there was a definitive diagnosis of IIH based on the Modified Dandy Criteria or clinical impression were identified. From this database search, a cohort of 281 patients was generated, each meeting the above inclusion criteria for IIH. Of those patients, the dictations were searched for the keywords “functional, non-organic.” If the clinical impression included FVL, then the chart was acquired and included for analysis. Outpatient neuro-ophthalmology records were obtained and underwent additional review to assess for features consistent with FVL. Suspected FVL was identified on the basis of standard clinical techniques, including tangent screen testing, automated and kinetic perimetry studies, optokinetic responses, prism dissociation testing, stereoacuity, and reverse Snellen acuity testing.7 Information on these tests and demographic characteristics, medical histories, management strategies, and recurrence of IIH were recorded for each patient with suspected FVL. Clinical data were obtained from initial and follow-up visits.
Results Presentation and Diagnosis of Functional Visual Loss A total of 17 patients had FVL and IIH. All of the patients were women aged 24 to 48 years, with an average age of 34 years, and each patient met the Modified Dandy Criteria. Eleven patients had FVL at the time of initial evaluation, and 6 patients developed FVL during follow-up. There were several common patterns of FVL (Table 1). All 17 patients had functional field defects, with accompanying decreased visual acuity (VA) in 6 patients. In each of those cases, VA fluctuated depending on effort and technique of examination. Thirteen of 17 patients had optic nerve–visual field mismatch, with healthy discs, that is, no edema or pallor in the setting of severe visual field loss. Four patients showed evidence of optic nerve pallor or gliosis, suggesting that FVL was superimposed on true vision loss. In all 4 of those patients, the ophthalmoscopic findings and reviewed visual fields were found to be incompatible with the observed level of visual function. Five patients had other functional components to their examination, including give-way weakness on strength testing.
Follow-up Follow-up information was available for all 17 patients. The duration of follow-up ranged from 1 to 160 months. The 17 patients were divided into 2 cohorts based on the timing of the diagnosis and the progression of their FVL. Group I comprised patients who had FVL at time of presentation, and group II comprised patients who initially presented with physiologic vision loss and then subsequently developed FVL. Table 2 summarizes the follow-up, progression, and management of FVL in each subpopulation.
Table 1. Functional Patterns of Visual Loss and Examination Patterns of FVL
No. of Patients (%)
Functional visual fields (all types) Tubular fields Nonphysiologic constriction Spiraling on GVF Crossing isopters on GVF Visual behavior mismatch Functional neurologic examinationa Monocular diplopia Nerve/field mismatchb Fluctuating (inconsistent) VA (without examination change)
17/17 (100) 14/17 (82) 12/17 (71) 2/17 (12) 2/17 (12) 9/17 (53) 5/17 (29) 3/17 (18) 13/17 (76) 6/17 (35)
FVL ⫽ functional visual loss; GVF ⫽ Goldmann visual field; VA ⫽ visual acuity. Most patients had multiple patterns of FVL. a Functional findings on neurologic examination include give-way weakness and nonlocalizing sensory and motor findings. b The 13 patients showed no sign of optic atrophy or gliosis; 4 patients had some optic nerve pallor thought to be too mild to explain visual field loss.
Eleven patients had FVL at initial presentation (group I), and at the time of their final visit, 8 of 11 patients had stabilization of their examination results, with persistent nonphysiologic visual fields in the presence of nonswollen optic nerves. Only 1 patient showed “improvement,” with 2 patients’ findings worsening. The diagnosis of FVL was made after initial presentation in 6 patients (group II), with all 6 patients’ functional findings stabilizing or improving on the last visit. Of the 2 patients who showed improvement in their FVL, neither patient showed complete normalization of their vision at the time of their last visit. Eleven patients, irrespective of the timing of diagnosis of FVL, had a functional or physiologic deterioration in examination or visual field after their first visit, with 9 of 11 patients eventually stabilizing or improving at the time of their last visit. Six of the 11 patients exhibited FVL on presentation, with the remaining 5 patients developing FVL after initial presentation. Two patients had progressive deterioration of their functional fields through their last visit. Five patients in this series underwent optic nerve sheath fenestration (ONSF) by the authors. These patients showed continued visual deterioration and lacked definitive evidence of vision loss being exclusively nonorganic. Four patients, 3 from group I and one from group II, continued to return for long-term follow-up. One patient had bilateral ONSF procedures before a diagnosis of FVL, and the other 3 patients were managed conservatively with acetazolamide, topiramate, and methylprednisolone. The patient who had an ONSF performed had been followed for 160 months (13 years) and secured long-term disability with persistent nonphysiologically constricted visual fields. Of the 3 patients managed conservatively, 1 showed progressive constriction and worsening of visual symptoms despite normal examination results with no evidence of papilledema or disc pallor. The other 2 patients had stabilization of FVL with persistent papilledema and no optic atrophy.
Surgical Intervention and Functional Visual Loss All of the patients received medical therapy at some point during the course of their IIH. Most were treated with acetazolamide only, with therapy switched to topiramate in 3 patients for headache management in the absence of any nerve swelling. Overall, 9 of 17 patients had surgery at some point in the management of their IIH, 4 before presentation to the authors and 5 while being observed at
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Ophthalmology Volume 116, Number 9, September 2009 Table 2. Follow-up Data Respective to Initial Presentation, Progression, and Treatment
Presentation/Management (Group)
Total Patients
FVL on presentation (I) ONSF Medical† FVL after initial presentation (II) ONSF Medical† Total Surgical㛳 Medical†
11 2 9‡ 6 3 3§ 17 9 (53%) 8 (47%)
Deterioration after Initial Visit 6 3 2 5 4 1 11 (65%) 8 (47%) 3 (18%)
FF Functional Examination Findings Stable/Improvement Worsen 9 2 7 6 3 2 15 (88%) 8 7
2 — 2 — — — 2 (12%) 1 1
Recur* 1 1 — 1 — 1 2 (12%) 1 1
FVL ⫽ functional visual loss; ONSF ⫽ optic nerve sheath fenestration; FF ⫽ follow-up findings. *Recurrence defined as resolution of papilledema subsequently followed by return of signs and symptoms of IIH. † Medical management includes acetazolamide, topiramate, and reassurance. ‡ Three patients in this group had surgery for IIH before presentation. § One patient in this group had surgery for IIH before presentation. 㛳 Surgery at any point in management of IIH.
our institution (Scheie Eye Institute/Hospital of the University of Pennsylvania). Three of the 4 patients who received prior surgery had evidence of optic nerve pallor or gliosis on presentation to the authors, again suggesting a component of true vision loss. Five patients received ONSF at some point after establishing their diagnosis of IIH at our institution. All 5 patients had physiologic deterioration in their visual examination; 3 of the 5 patients had evidence of FVL before surgery, 2 with FVL on presentation. Of those, 1 patient had progressive loss on both Humphrey visual field and Goldmann visual field (GVF) testing, and the other patient had resolution of IIH and FVL and subsequently had a recurrence with physiologic field loss and a relative afferent pupillary defect. In each case, there was enough objective evidence to warrant surgical intervention (e.g., disc pallor, physiologic field patterns, relative afferent pupillary defect, and persistent refractory papilledema), yet clearly the degree of functional overlay made it impossible to determine what component of the vision loss was organic. Figure 1 describes one such patient who had physiologic visual loss at presentation and developed FVL after an ONSF.
Significant Psychiatric and Medical History Many patients had significant psychiatric and medical comorbidities in addition to psychosocial concerns that further complicated their management (Table 3). Three patients had bipolar disorder, and 4 patients had substance abuse disorders. Of note, 4 patients had active disability claims, including 1 patient undergoing Blind Services Training. One patient with bipolar disorder showed improvement in her FVL and IIH only after effectively treating her psychiatric illness. In addition, 10 patients had concomitant chronic disease (Table 3), 6 patients had at least 1 comorbidity, and 8 patients had multiple contributing comorbidities.
Illustrative Cases Case 1. A 38-year-old woman had been observed by a neuroophthalmologist for 10 years for IIH management requiring aggressive treatment that included bilateral ONSF, but she continued to have unexplained severe vision loss. Previous records documented functional features in the examination. She presented with persistent “tunnel vision,” with increased headaches and progres-
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sive vision loss leaving her unable to read or perform her standard activities of daily living. Her medical history was significant for poorly controlled diabetes requiring several hospitalizations for blood glucose management. On examination, her VA was 20/200 and 20/400; however, with both eyes open she could see the 20/60 letters. Her pupils were sluggish, but there was no relative afferent pupillary defect. Both optic nerves showed mild gliosis but were otherwise healthy; however, optic neuropathy from recurrence without papilledema could not be ruled out. On GVF she exhibited a 3-degree central island of vision, despite being able to freely ambulate around the examination room. The patient was able to mimic movements in her peripheral visual field, indicating a functional presentation. The patient was administered acetazolamide for headache management. Despite medical management and reassurance, she continued to have intractable headaches and deteriorating vision and initiated training with Blind Services. No further surgical intervention was pursued, because her inconsistent examination results and symptoms made it difficult to distinguish organic from functionally derived symptoms. Figure 2 (available at http://aaojournal.org) shows initial and follow-up disc photographs and corresponding GVF for Case 1. Case 2. A 24-year-old woman with blurred vision, visual obscurations, and persistent headaches presented to our group for management of her presumed IIH. Magnetic resonance imaging of the brain showed flattening of the posterior globes but was otherwise normal. She had been treated with increasing dosages of acetazolamide with no relief of her headaches or visual symptoms. On examination, her VA was 20/70 and 20/100, although she easily counted the number of letters on the 20/30 line, suggesting her VA was at least 20/50, and she had intact stereovision, implying that her vision was probably at least 20/40 to 20/20 in both eyes.7 Her GVF showed a tiny spiral of vision in a nonorganic pattern. She had nonatrophic bilateral papilledema on ophthalmoscopic examination. Before her second appointment, she had a lumbar puncture with an opening pressure of 35 cm and normal brain magnetic resonance venography results. Medical management was continued with some improvement of her nerve swelling, although her visual fields remained generally constricted. The patient was lost to follow-up after 4 visits. At the time of her last visit, she had persistent papilledema and FVL.
Ney et al 䡠 FVL in IIH
Figure 1. Optic disc photographs and corresponding GVF and Humphrey visual field results of a patient who had physiologic visual loss at presentation and an ONSF of the left optic nerve and subsequently developed FVL. At presentation, the patient had papilledema OU with a nasal defect OD and generalized constriction OS (A, B, G, H). Photographs and Humphrey visual field results 1 month postoperatively showed improvement in both papilledema and field defects (C, D, I, J). The patient’s optic nerves showed no sign of swelling or pallor 2 months postoperatively; however, she had severe, nonphysiologic constriction on Humphrey visual field testing, clearly exhibiting nerve–field mismatch (E, F, K, L). At that time, FVL was first suspected, and confirmatory GVF testing was conducted again, exhibiting a nonphysiologic pattern (M, N). The patient also had tubular fields on tangent screen testing and despite dense field defects could ambulate around the examination room without difficulty. FVL ⫽ functional visual loss; GVF ⫽ Goldmann visual field; OD ⫽ right eye; ONSF ⫽ optic nerve sheath fenestration; OS ⫽ left eye; OU ⫽ each eye.
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Ophthalmology Volume 116, Number 9, September 2009 Table 3. Concomitant Psychiatric and Psychosocial Stressors Relevant History
No. of Patients (%)
Mood disorder Substance abuse Malingering Borderline personality disorder Chronic disease* MVA Social history† Multiple factors Total No. of patients‡
4/17 (24) 4/17 (24) 4/17 (24) 1/17 (6) 10/17 (59) 1/17 (6) 1/17 (6) 8/17 (47) 15/17 (88)
MVA ⫽ motor vehicle accident. *Chronic diseases included fibromyalgia, systemic lupus erythematosus, hyperthyroidism, morbid obesity, malignant hypertension, diabetes, stroke, multiple sclerosis, obstructive sleep apnea, Crohn’s disease, and asthma. † One patient was living in a halfway house and periodically homeless. ‡ Total number of patients with at least 1 relevant historical finding.
Discussion Care should be taken when evaluating patients with advanced visual field loss and IIH. Advanced vision loss is commonly diagnosed on the basis of progressive constriction of the automated visual field with only mild reductions in VA. This type of constriction of the visual field is also common in patients with FVL. Little has been written about FVL in IIH since Corbett et al8 reported hysterical vision loss in 2 of 29 patients with IIH and vision loss. Several studies of visual field loss in IIH did not identify any patients with FVL.3–5,8 –10 Scott and Egan2 recently described IIH as one of many diseases potentially correlated with FVL. There was significant variability in length of follow-up for patients in our cohort, with the majority of patients showing stabilization and persistence of FVL and only 2 patients showing improvement. Functional fields were identified in all 17 patients through a series of confirmatory measures, including tangent screen testing and Goldmann perimetry. The disease course in many of the patients was complicated by psychiatric and chronic medical illnesses. Treatment course varied; however, the majority of patients underwent surgery at some point in their management of IIH. The chronic and unstable disease course of IIH stresses the importance of long-term follow-up. A retrospective analysis of 54 patients with IIH identified 21 patients (38%) with multiple episodes of IIH; another study identified a recurrence rate of 15%.11,12 In patients with superimposed FVL, the task of accurately monitoring disease progression by conventional methods is compromised, whereas interventions to treat recurrence may further reinforce the functional components of their visual loss. Persistence of FVL poses unique challenges, particularly when coinciding with an organic disease with a propensity for recurrence. The progression of FVL alone is difficult to predict; however, the complex nature of IIH makes prognostication particularly challenging. In previously published reports, resolution of pure FVL has been highly variable.
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Several studies have found a wide distribution of resolution rates ranging from 9% to 96%; however, results are skewed by poor follow-up and vary depending on the type of FVL.13,14 In our patients, the persistence of FVL may be attributable to their antecedent and overlying IIH, perhaps offering justification to the patient for their perception of ongoing visual problems. In general, the rule in the management for pure FVL is reassurance and long-term follow-up. Clearly, reassurance alone is insufficient when treating patients with known organic disease with the potential to permanently affect vision. Four of our patients had a component of true vision loss concurrently (based on the presence of atrophic papilledema) or in the past (disc pallor at presentation). This distinction between pure FVL and functional overlay is particularly concerning when deciding between conservative management and surgery. It was not surprising that many of our patients agreed to undergo ONSF or shunting procedures. Although ONSF is a relatively safe procedure, it has been reported that there is failure rate of 13% requiring reoperation, with common complications of the surgery including transient extraocular muscle dysfunction and, rarely, ischemic injury leading to postoperative blindness.15 Their decision to agree to surgery may be predicated on an awareness that something may indeed be wrong and that they have begun to believe their own fabrications, a phenomenon previously described as the “worried imposter.”16 Their adamancy creates a confrontational doctor–patient relationship, potentially steering management away from reassurance toward surgical intervention. Certainly, unnecessary surgical procedures should be avoided, particularly when aggressive interventions could reinforce the potential psychiatric foundation of a patient’s FVL. The prevalence of FVL in IIH is unknown; however, a predisposition to developing FVL may exist because of demographic factors related to this patient population. Specifically, obesity and weight gain have been directly correlated with IIH persistence and recurrence, while having a direct detrimental affect on health-related quality of life scores.17 In addition, obesity and body mass index have been shown to correlate with psychiatric illness and personality disorders.18 –20 In our cohort, several patients had multiple psychiatric and medical comorbidities that may have contributed to or exacerbated their clinical condition. Although there have been no reports definitively linking depression and chronic disease with FVL, Lim et al16 found a concurrence rate of 39% in a cohort of 82 adult patients with FVL. There is little doubt that identifying and aggressively managing psychiatric comorbidities would improve quality of life and potentially enhance a patient’s coping mechanisms. In conclusion, IIH is a chronic disease that requires long-term follow-up. This study identifies FVL as a component of the complicated clinical picture of patients with IIH. Prudent management may include monitoring for FVL, particularly in those patients with cases refractory to maximal medical and surgical therapy. This study is limited by the confines of a retrospective analysis with bias in data collection and variability in workup and documentation. The technique in which pa-
Ney et al 䡠 FVL in IIH tients were identified with FVL was imprecise, with the potential for missing patients with suspected FVL. Although a prospective study of IIH and FVL would be ideal, our retrospective series of IIH suggests that the prevalence of FVL is relatively low and that some patients may be reluctant to consent to a study after FVL.
References
11. 12. 13.
1. Bose S, Kupersmith MJ. Neuro-ophthalmologic presentations of functional visual disorders. Neurol Clin 1995;13:321–39. 2. Scott JA, Egan RA. Prevalence of organic neuro-ophthalmologic disease in patients with functional visual loss. Am J Ophthalmol 2003;135:670 –5. 3. Durcan FJ, Corbett JJ, Wall M. The incidence of pseudotumor cerebri: population studies in Iowa and Louisiana. Arch Neurol 1988;45:857–7. 4. Wall M, George D. Idiopathic intracranial hypertension: a prospective study of 50 patients. Brain 1991;114:155– 80. 5. Orcutt JC, Page NG, Sanders MD. Factors affecting visual loss in benign intracranial hypertension. Ophthalmology 1984; 91:1303–12. 6. Friedman DI, Jacobson DM. Diagnostic criteria for idiopathic intracranial hypertension. Neurology 2002;59:1492–5. 7. Shindler KS, Galetta SL, Volpe NJ. Functional visual loss. Curr Treat Options Neurol 2004;6:67–73. 8. Corbett JJ, Savino PJ, Thompson HS, et al. Vision loss in pseudotumor cerebri: follow-up of 57 patients from five to 41 years and a profile of 14 patients with permanent severe vision loss. Arch Neurol 1982;39:461–74. 9. Smith TJ, Baker RS. Perimetric findings in pseudotumor cerebri using automated techniques. Ophthalmology 1986;93: 887–94. 10. Spoor TC, Ramocki JM, Madion MP, Wilkinson MJ. Treatment of pseudotumor cerebri by primary and secondary optic
14. 15.
16. 17.
18. 19. 20.
nerve sheath decompression. Am J Ophthalmol 1991;112: 177– 85. Kesler A, Hadayer A, Goldhammer Y, et al. Idiopathic intracranial hypertension: risk of recurrences. Neurology 2004;63: 1737–9. Shah VA, Kardon RH, Lee AG, et al. Long-term follow-up of idiopathic intracranial hypertension: the Iowa experience. Neurology 2008;70:634 – 40. Kathol RG, Cox TA, Corbett JJ, Thompson HS. Functional visual loss: follow-up of 42 cases. Arch Ophthalmol 1983; 101:729 –35. Lim SA, Siatkowski RM, Farris BK. Functional visual loss in adults and children: patient characteristics, management, and outcomes. Ophthalmology 2005;112:1821– 8. Agarwal MR, Yoo JH. Optic nerve sheath fenestration for vision preservation in idiopathic intracranial hypertension. Neurosurg Focus [serial online] 2007;23:E7. Available at: http://thejns.org/doi/pdf/10.3171/FOC-07/11/E7. Accessed March 1, 2009. Thompson HS. Functional visual loss. Am J Ophthalmol 1985;100:209 –13. Daniels AB, Liu GT, Volpe NJ, et al. Profiles of obesity, weight gain, and quality of life in idiopathic intracranial hypertension (pseudotumor cerebri). Am J Ophthalmol 2007; 143:635– 41. Black DW, Goldstein RB, Mason EE. Prevalence of mental disorder in 88 morbidly obese bariatric clinic patients. Am J Psychiatry 1992;149:227–34. O’Neil PM, Jarrell MP. Psychological aspects of obesity and very-low-calorie diets. Am J Clin Nutr 1992;56(suppl): 185S–9S. Barry D, Pietrzak RH, Petry NM. Gender differences in associations between body mass index and DSM-IV mood and anxiety disorders: results from the National Epidemiologic Survey on Alcohol and Related Conditions. Ann Epidemiol 2008;18:458 – 66.
Footnotes and Financial Disclosures Originally received: October 19, 2008. Final revision: March 16, 2009. Accepted: March 24, 2009. Available online: May 1, 2009.
Presented at: the American Academy of Ophthalmology Annual Meeting, November 2008, Atlanta, Georgia. Manuscript no. 2008-1236.
1 Departments of Neurology and Ophthalmology, Scheie Eye Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania. 2
Department of Neurosensory Sciences, Albert Einstein Medical Center, Philadelphia, Pennsylvania.
Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Correspondence: Nicholas J. Volpe, MD, Scheie Eye Institute, 51 North 39th Street, Philadelphia, PA 19104. E-mail: [email protected].
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Figure 2. Case 1. Optic disc photographs and corresponding GVF results at initial visit (A, B) and return visit 2 years later (C, D). Both eyes showed mild gliosis, but there was no evidence of nerve pallor. The small islands of vision demonstrated on GVF testing conflicted with the patient’s ability to mimic movements in the patient’s peripheral vision and ambulate around the examination room. The patient had FVL on presentation to the time of the patient’s last visit. GVF ⫽ Goldmann visual field; FVL ⫽ functional visual loss.
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Functional or nonorganic visual loss refers to loss of vision that cannot be explained by pathology of the eye or visual pathway. Recent reviews have cited a prevalence of functional visual loss (FVL) ranging from 5% to 12% of patients who present with visual loss to a neuro-ophthalmologist.1 Concomitant organic disease has been reported in up to 53% of patients with FVL.2 Such observations reinforce the necessity for practitioners’ persistent vigilance in identifying organic disease in patients with FVL, recognizing the potential association between certain diseases and FVL. Our goal was to describe an association observed in patients diagnosed with idiopathic intracranial hypertension (IIH) with concomitant FVL. Idiopathic intracranial hypertension has an incidence reported to be as high as 20 per 100 000 people and typically occurs in obese women of childbearing age.3 The natural history of the disease is variable, with most cases protracted over months to years. Visual disturbances are nearly universal, ranging from visual blurring or transient visual obscurations to visual field loss.4,5 The defects are usually asymptomatic and include enlargement of the natural blind spot, arcuate defects, or generalized constriction of the visual field. These defects often resolve after optic nerve swelling resolution. Despite the relatively benign disease progression, clinicians need to be vigilant in screening for visual loss that would suggest a more fulminant course,
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© 2009 by the American Academy of Ophthalmology Published by Elsevier Inc.
because up to 5% to 30% will have permanent significant visual field loss, defined as progressive deterioration of visual fields.4 Functional visual loss superimposed on IIH would also complicate decision-making regarding surgical intervention. Although there have been studies evaluating the concurrence of certain functional patterns and organic disease, the relationship of FVL and IIH has not been extensively described. The purpose of this study is to characterize the patterns of FVL in IIH and identify any predisposing characteristics, such as psychiatric illness, that may put this patient population at risk for developing FVL.
Materials and Methods We performed a retrospective chart review of 281 patients with the diagnosis of IIH evaluated at the University of Pennsylvania Hospitals and Albert Einstein Medical Center, Departments of Neurology and Ophthalmology, from January 1995 to December 2007. Institutional review board approval was obtained, and the study was conducted in accordance with the Health Insurance Portability and Accountability Act guidelines. Inclusion criteria included (1) patients at least 18 years of age, evaluated and followed by a neuro-ophthalmologist, and (2) a diagnosis of IIH fulfilling the Modified Dandy Criteria6 or made on the ISSN 0161-6420/09/$–see front matter doi:10.1016/j.ophtha.2009.03.056
Ney et al 䡠 FVL in IIH clinical impression of the neuro-ophthalmologist. Patients were excluded from this study if adequate follow-up data were unavailable. We generated a patient list with International Statistical Classification of Diseases Ninth Revision codes 348.2 and 377.01 for “benign intracranial hypertension” and “papilledema associated with increased intracranial pressure,” respectively. This list was supplemented with the personal databases of patients with IIH seen by NJV, GTL, LJB, MLM, and SLG. We compiled a digital archive of available Microsoft Word (Microsoft Corp, Redmond, WA) dictation notes from all patient visits during the specified time period. The archive was searched for each name on the master IIH list. Patients for whom there was a definitive diagnosis of IIH based on the Modified Dandy Criteria or clinical impression were identified. From this database search, a cohort of 281 patients was generated, each meeting the above inclusion criteria for IIH. Of those patients, the dictations were searched for the keywords “functional, non-organic.” If the clinical impression included FVL, then the chart was acquired and included for analysis. Outpatient neuro-ophthalmology records were obtained and underwent additional review to assess for features consistent with FVL. Suspected FVL was identified on the basis of standard clinical techniques, including tangent screen testing, automated and kinetic perimetry studies, optokinetic responses, prism dissociation testing, stereoacuity, and reverse Snellen acuity testing.7 Information on these tests and demographic characteristics, medical histories, management strategies, and recurrence of IIH were recorded for each patient with suspected FVL. Clinical data were obtained from initial and follow-up visits.
Results Presentation and Diagnosis of Functional Visual Loss A total of 17 patients had FVL and IIH. All of the patients were women aged 24 to 48 years, with an average age of 34 years, and each patient met the Modified Dandy Criteria. Eleven patients had FVL at the time of initial evaluation, and 6 patients developed FVL during follow-up. There were several common patterns of FVL (Table 1). All 17 patients had functional field defects, with accompanying decreased visual acuity (VA) in 6 patients. In each of those cases, VA fluctuated depending on effort and technique of examination. Thirteen of 17 patients had optic nerve–visual field mismatch, with healthy discs, that is, no edema or pallor in the setting of severe visual field loss. Four patients showed evidence of optic nerve pallor or gliosis, suggesting that FVL was superimposed on true vision loss. In all 4 of those patients, the ophthalmoscopic findings and reviewed visual fields were found to be incompatible with the observed level of visual function. Five patients had other functional components to their examination, including give-way weakness on strength testing.
Follow-up Follow-up information was available for all 17 patients. The duration of follow-up ranged from 1 to 160 months. The 17 patients were divided into 2 cohorts based on the timing of the diagnosis and the progression of their FVL. Group I comprised patients who had FVL at time of presentation, and group II comprised patients who initially presented with physiologic vision loss and then subsequently developed FVL. Table 2 summarizes the follow-up, progression, and management of FVL in each subpopulation.
Table 1. Functional Patterns of Visual Loss and Examination Patterns of FVL
No. of Patients (%)
Functional visual fields (all types) Tubular fields Nonphysiologic constriction Spiraling on GVF Crossing isopters on GVF Visual behavior mismatch Functional neurologic examinationa Monocular diplopia Nerve/field mismatchb Fluctuating (inconsistent) VA (without examination change)
17/17 (100) 14/17 (82) 12/17 (71) 2/17 (12) 2/17 (12) 9/17 (53) 5/17 (29) 3/17 (18) 13/17 (76) 6/17 (35)
FVL ⫽ functional visual loss; GVF ⫽ Goldmann visual field; VA ⫽ visual acuity. Most patients had multiple patterns of FVL. a Functional findings on neurologic examination include give-way weakness and nonlocalizing sensory and motor findings. b The 13 patients showed no sign of optic atrophy or gliosis; 4 patients had some optic nerve pallor thought to be too mild to explain visual field loss.
Eleven patients had FVL at initial presentation (group I), and at the time of their final visit, 8 of 11 patients had stabilization of their examination results, with persistent nonphysiologic visual fields in the presence of nonswollen optic nerves. Only 1 patient showed “improvement,” with 2 patients’ findings worsening. The diagnosis of FVL was made after initial presentation in 6 patients (group II), with all 6 patients’ functional findings stabilizing or improving on the last visit. Of the 2 patients who showed improvement in their FVL, neither patient showed complete normalization of their vision at the time of their last visit. Eleven patients, irrespective of the timing of diagnosis of FVL, had a functional or physiologic deterioration in examination or visual field after their first visit, with 9 of 11 patients eventually stabilizing or improving at the time of their last visit. Six of the 11 patients exhibited FVL on presentation, with the remaining 5 patients developing FVL after initial presentation. Two patients had progressive deterioration of their functional fields through their last visit. Five patients in this series underwent optic nerve sheath fenestration (ONSF) by the authors. These patients showed continued visual deterioration and lacked definitive evidence of vision loss being exclusively nonorganic. Four patients, 3 from group I and one from group II, continued to return for long-term follow-up. One patient had bilateral ONSF procedures before a diagnosis of FVL, and the other 3 patients were managed conservatively with acetazolamide, topiramate, and methylprednisolone. The patient who had an ONSF performed had been followed for 160 months (13 years) and secured long-term disability with persistent nonphysiologically constricted visual fields. Of the 3 patients managed conservatively, 1 showed progressive constriction and worsening of visual symptoms despite normal examination results with no evidence of papilledema or disc pallor. The other 2 patients had stabilization of FVL with persistent papilledema and no optic atrophy.
Surgical Intervention and Functional Visual Loss All of the patients received medical therapy at some point during the course of their IIH. Most were treated with acetazolamide only, with therapy switched to topiramate in 3 patients for headache management in the absence of any nerve swelling. Overall, 9 of 17 patients had surgery at some point in the management of their IIH, 4 before presentation to the authors and 5 while being observed at
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Ophthalmology Volume 116, Number 9, September 2009 Table 2. Follow-up Data Respective to Initial Presentation, Progression, and Treatment
Presentation/Management (Group)
Total Patients
FVL on presentation (I) ONSF Medical† FVL after initial presentation (II) ONSF Medical† Total Surgical㛳 Medical†
11 2 9‡ 6 3 3§ 17 9 (53%) 8 (47%)
Deterioration after Initial Visit 6 3 2 5 4 1 11 (65%) 8 (47%) 3 (18%)
FF Functional Examination Findings Stable/Improvement Worsen 9 2 7 6 3 2 15 (88%) 8 7
2 — 2 — — — 2 (12%) 1 1
Recur* 1 1 — 1 — 1 2 (12%) 1 1
FVL ⫽ functional visual loss; ONSF ⫽ optic nerve sheath fenestration; FF ⫽ follow-up findings. *Recurrence defined as resolution of papilledema subsequently followed by return of signs and symptoms of IIH. † Medical management includes acetazolamide, topiramate, and reassurance. ‡ Three patients in this group had surgery for IIH before presentation. § One patient in this group had surgery for IIH before presentation. 㛳 Surgery at any point in management of IIH.
our institution (Scheie Eye Institute/Hospital of the University of Pennsylvania). Three of the 4 patients who received prior surgery had evidence of optic nerve pallor or gliosis on presentation to the authors, again suggesting a component of true vision loss. Five patients received ONSF at some point after establishing their diagnosis of IIH at our institution. All 5 patients had physiologic deterioration in their visual examination; 3 of the 5 patients had evidence of FVL before surgery, 2 with FVL on presentation. Of those, 1 patient had progressive loss on both Humphrey visual field and Goldmann visual field (GVF) testing, and the other patient had resolution of IIH and FVL and subsequently had a recurrence with physiologic field loss and a relative afferent pupillary defect. In each case, there was enough objective evidence to warrant surgical intervention (e.g., disc pallor, physiologic field patterns, relative afferent pupillary defect, and persistent refractory papilledema), yet clearly the degree of functional overlay made it impossible to determine what component of the vision loss was organic. Figure 1 describes one such patient who had physiologic visual loss at presentation and developed FVL after an ONSF.
Significant Psychiatric and Medical History Many patients had significant psychiatric and medical comorbidities in addition to psychosocial concerns that further complicated their management (Table 3). Three patients had bipolar disorder, and 4 patients had substance abuse disorders. Of note, 4 patients had active disability claims, including 1 patient undergoing Blind Services Training. One patient with bipolar disorder showed improvement in her FVL and IIH only after effectively treating her psychiatric illness. In addition, 10 patients had concomitant chronic disease (Table 3), 6 patients had at least 1 comorbidity, and 8 patients had multiple contributing comorbidities.
Illustrative Cases Case 1. A 38-year-old woman had been observed by a neuroophthalmologist for 10 years for IIH management requiring aggressive treatment that included bilateral ONSF, but she continued to have unexplained severe vision loss. Previous records documented functional features in the examination. She presented with persistent “tunnel vision,” with increased headaches and progres-
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sive vision loss leaving her unable to read or perform her standard activities of daily living. Her medical history was significant for poorly controlled diabetes requiring several hospitalizations for blood glucose management. On examination, her VA was 20/200 and 20/400; however, with both eyes open she could see the 20/60 letters. Her pupils were sluggish, but there was no relative afferent pupillary defect. Both optic nerves showed mild gliosis but were otherwise healthy; however, optic neuropathy from recurrence without papilledema could not be ruled out. On GVF she exhibited a 3-degree central island of vision, despite being able to freely ambulate around the examination room. The patient was able to mimic movements in her peripheral visual field, indicating a functional presentation. The patient was administered acetazolamide for headache management. Despite medical management and reassurance, she continued to have intractable headaches and deteriorating vision and initiated training with Blind Services. No further surgical intervention was pursued, because her inconsistent examination results and symptoms made it difficult to distinguish organic from functionally derived symptoms. Figure 2 (available at http://aaojournal.org) shows initial and follow-up disc photographs and corresponding GVF for Case 1. Case 2. A 24-year-old woman with blurred vision, visual obscurations, and persistent headaches presented to our group for management of her presumed IIH. Magnetic resonance imaging of the brain showed flattening of the posterior globes but was otherwise normal. She had been treated with increasing dosages of acetazolamide with no relief of her headaches or visual symptoms. On examination, her VA was 20/70 and 20/100, although she easily counted the number of letters on the 20/30 line, suggesting her VA was at least 20/50, and she had intact stereovision, implying that her vision was probably at least 20/40 to 20/20 in both eyes.7 Her GVF showed a tiny spiral of vision in a nonorganic pattern. She had nonatrophic bilateral papilledema on ophthalmoscopic examination. Before her second appointment, she had a lumbar puncture with an opening pressure of 35 cm and normal brain magnetic resonance venography results. Medical management was continued with some improvement of her nerve swelling, although her visual fields remained generally constricted. The patient was lost to follow-up after 4 visits. At the time of her last visit, she had persistent papilledema and FVL.
Ney et al 䡠 FVL in IIH
Figure 1. Optic disc photographs and corresponding GVF and Humphrey visual field results of a patient who had physiologic visual loss at presentation and an ONSF of the left optic nerve and subsequently developed FVL. At presentation, the patient had papilledema OU with a nasal defect OD and generalized constriction OS (A, B, G, H). Photographs and Humphrey visual field results 1 month postoperatively showed improvement in both papilledema and field defects (C, D, I, J). The patient’s optic nerves showed no sign of swelling or pallor 2 months postoperatively; however, she had severe, nonphysiologic constriction on Humphrey visual field testing, clearly exhibiting nerve–field mismatch (E, F, K, L). At that time, FVL was first suspected, and confirmatory GVF testing was conducted again, exhibiting a nonphysiologic pattern (M, N). The patient also had tubular fields on tangent screen testing and despite dense field defects could ambulate around the examination room without difficulty. FVL ⫽ functional visual loss; GVF ⫽ Goldmann visual field; OD ⫽ right eye; ONSF ⫽ optic nerve sheath fenestration; OS ⫽ left eye; OU ⫽ each eye.
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Ophthalmology Volume 116, Number 9, September 2009 Table 3. Concomitant Psychiatric and Psychosocial Stressors Relevant History
No. of Patients (%)
Mood disorder Substance abuse Malingering Borderline personality disorder Chronic disease* MVA Social history† Multiple factors Total No. of patients‡
4/17 (24) 4/17 (24) 4/17 (24) 1/17 (6) 10/17 (59) 1/17 (6) 1/17 (6) 8/17 (47) 15/17 (88)
MVA ⫽ motor vehicle accident. *Chronic diseases included fibromyalgia, systemic lupus erythematosus, hyperthyroidism, morbid obesity, malignant hypertension, diabetes, stroke, multiple sclerosis, obstructive sleep apnea, Crohn’s disease, and asthma. † One patient was living in a halfway house and periodically homeless. ‡ Total number of patients with at least 1 relevant historical finding.
Discussion Care should be taken when evaluating patients with advanced visual field loss and IIH. Advanced vision loss is commonly diagnosed on the basis of progressive constriction of the automated visual field with only mild reductions in VA. This type of constriction of the visual field is also common in patients with FVL. Little has been written about FVL in IIH since Corbett et al8 reported hysterical vision loss in 2 of 29 patients with IIH and vision loss. Several studies of visual field loss in IIH did not identify any patients with FVL.3–5,8 –10 Scott and Egan2 recently described IIH as one of many diseases potentially correlated with FVL. There was significant variability in length of follow-up for patients in our cohort, with the majority of patients showing stabilization and persistence of FVL and only 2 patients showing improvement. Functional fields were identified in all 17 patients through a series of confirmatory measures, including tangent screen testing and Goldmann perimetry. The disease course in many of the patients was complicated by psychiatric and chronic medical illnesses. Treatment course varied; however, the majority of patients underwent surgery at some point in their management of IIH. The chronic and unstable disease course of IIH stresses the importance of long-term follow-up. A retrospective analysis of 54 patients with IIH identified 21 patients (38%) with multiple episodes of IIH; another study identified a recurrence rate of 15%.11,12 In patients with superimposed FVL, the task of accurately monitoring disease progression by conventional methods is compromised, whereas interventions to treat recurrence may further reinforce the functional components of their visual loss. Persistence of FVL poses unique challenges, particularly when coinciding with an organic disease with a propensity for recurrence. The progression of FVL alone is difficult to predict; however, the complex nature of IIH makes prognostication particularly challenging. In previously published reports, resolution of pure FVL has been highly variable.
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Several studies have found a wide distribution of resolution rates ranging from 9% to 96%; however, results are skewed by poor follow-up and vary depending on the type of FVL.13,14 In our patients, the persistence of FVL may be attributable to their antecedent and overlying IIH, perhaps offering justification to the patient for their perception of ongoing visual problems. In general, the rule in the management for pure FVL is reassurance and long-term follow-up. Clearly, reassurance alone is insufficient when treating patients with known organic disease with the potential to permanently affect vision. Four of our patients had a component of true vision loss concurrently (based on the presence of atrophic papilledema) or in the past (disc pallor at presentation). This distinction between pure FVL and functional overlay is particularly concerning when deciding between conservative management and surgery. It was not surprising that many of our patients agreed to undergo ONSF or shunting procedures. Although ONSF is a relatively safe procedure, it has been reported that there is failure rate of 13% requiring reoperation, with common complications of the surgery including transient extraocular muscle dysfunction and, rarely, ischemic injury leading to postoperative blindness.15 Their decision to agree to surgery may be predicated on an awareness that something may indeed be wrong and that they have begun to believe their own fabrications, a phenomenon previously described as the “worried imposter.”16 Their adamancy creates a confrontational doctor–patient relationship, potentially steering management away from reassurance toward surgical intervention. Certainly, unnecessary surgical procedures should be avoided, particularly when aggressive interventions could reinforce the potential psychiatric foundation of a patient’s FVL. The prevalence of FVL in IIH is unknown; however, a predisposition to developing FVL may exist because of demographic factors related to this patient population. Specifically, obesity and weight gain have been directly correlated with IIH persistence and recurrence, while having a direct detrimental affect on health-related quality of life scores.17 In addition, obesity and body mass index have been shown to correlate with psychiatric illness and personality disorders.18 –20 In our cohort, several patients had multiple psychiatric and medical comorbidities that may have contributed to or exacerbated their clinical condition. Although there have been no reports definitively linking depression and chronic disease with FVL, Lim et al16 found a concurrence rate of 39% in a cohort of 82 adult patients with FVL. There is little doubt that identifying and aggressively managing psychiatric comorbidities would improve quality of life and potentially enhance a patient’s coping mechanisms. In conclusion, IIH is a chronic disease that requires long-term follow-up. This study identifies FVL as a component of the complicated clinical picture of patients with IIH. Prudent management may include monitoring for FVL, particularly in those patients with cases refractory to maximal medical and surgical therapy. This study is limited by the confines of a retrospective analysis with bias in data collection and variability in workup and documentation. The technique in which pa-
Ney et al 䡠 FVL in IIH tients were identified with FVL was imprecise, with the potential for missing patients with suspected FVL. Although a prospective study of IIH and FVL would be ideal, our retrospective series of IIH suggests that the prevalence of FVL is relatively low and that some patients may be reluctant to consent to a study after FVL.
References
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1. Bose S, Kupersmith MJ. Neuro-ophthalmologic presentations of functional visual disorders. Neurol Clin 1995;13:321–39. 2. Scott JA, Egan RA. Prevalence of organic neuro-ophthalmologic disease in patients with functional visual loss. Am J Ophthalmol 2003;135:670 –5. 3. Durcan FJ, Corbett JJ, Wall M. The incidence of pseudotumor cerebri: population studies in Iowa and Louisiana. Arch Neurol 1988;45:857–7. 4. Wall M, George D. Idiopathic intracranial hypertension: a prospective study of 50 patients. Brain 1991;114:155– 80. 5. Orcutt JC, Page NG, Sanders MD. Factors affecting visual loss in benign intracranial hypertension. Ophthalmology 1984; 91:1303–12. 6. Friedman DI, Jacobson DM. Diagnostic criteria for idiopathic intracranial hypertension. Neurology 2002;59:1492–5. 7. Shindler KS, Galetta SL, Volpe NJ. Functional visual loss. Curr Treat Options Neurol 2004;6:67–73. 8. Corbett JJ, Savino PJ, Thompson HS, et al. Vision loss in pseudotumor cerebri: follow-up of 57 patients from five to 41 years and a profile of 14 patients with permanent severe vision loss. Arch Neurol 1982;39:461–74. 9. Smith TJ, Baker RS. Perimetric findings in pseudotumor cerebri using automated techniques. Ophthalmology 1986;93: 887–94. 10. Spoor TC, Ramocki JM, Madion MP, Wilkinson MJ. Treatment of pseudotumor cerebri by primary and secondary optic
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nerve sheath decompression. Am J Ophthalmol 1991;112: 177– 85. Kesler A, Hadayer A, Goldhammer Y, et al. Idiopathic intracranial hypertension: risk of recurrences. Neurology 2004;63: 1737–9. Shah VA, Kardon RH, Lee AG, et al. Long-term follow-up of idiopathic intracranial hypertension: the Iowa experience. Neurology 2008;70:634 – 40. Kathol RG, Cox TA, Corbett JJ, Thompson HS. Functional visual loss: follow-up of 42 cases. Arch Ophthalmol 1983; 101:729 –35. Lim SA, Siatkowski RM, Farris BK. Functional visual loss in adults and children: patient characteristics, management, and outcomes. Ophthalmology 2005;112:1821– 8. Agarwal MR, Yoo JH. Optic nerve sheath fenestration for vision preservation in idiopathic intracranial hypertension. Neurosurg Focus [serial online] 2007;23:E7. Available at: http://thejns.org/doi/pdf/10.3171/FOC-07/11/E7. Accessed March 1, 2009. Thompson HS. Functional visual loss. Am J Ophthalmol 1985;100:209 –13. Daniels AB, Liu GT, Volpe NJ, et al. Profiles of obesity, weight gain, and quality of life in idiopathic intracranial hypertension (pseudotumor cerebri). Am J Ophthalmol 2007; 143:635– 41. Black DW, Goldstein RB, Mason EE. Prevalence of mental disorder in 88 morbidly obese bariatric clinic patients. Am J Psychiatry 1992;149:227–34. O’Neil PM, Jarrell MP. Psychological aspects of obesity and very-low-calorie diets. Am J Clin Nutr 1992;56(suppl): 185S–9S. Barry D, Pietrzak RH, Petry NM. Gender differences in associations between body mass index and DSM-IV mood and anxiety disorders: results from the National Epidemiologic Survey on Alcohol and Related Conditions. Ann Epidemiol 2008;18:458 – 66.
Footnotes and Financial Disclosures Originally received: October 19, 2008. Final revision: March 16, 2009. Accepted: March 24, 2009. Available online: May 1, 2009.
Presented at: the American Academy of Ophthalmology Annual Meeting, November 2008, Atlanta, Georgia. Manuscript no. 2008-1236.
1 Departments of Neurology and Ophthalmology, Scheie Eye Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania. 2
Department of Neurosensory Sciences, Albert Einstein Medical Center, Philadelphia, Pennsylvania.
Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Correspondence: Nicholas J. Volpe, MD, Scheie Eye Institute, 51 North 39th Street, Philadelphia, PA 19104. E-mail: [email protected].
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Figure 2. Case 1. Optic disc photographs and corresponding GVF results at initial visit (A, B) and return visit 2 years later (C, D). Both eyes showed mild gliosis, but there was no evidence of nerve pallor. The small islands of vision demonstrated on GVF testing conflicted with the patient’s ability to mimic movements in the patient’s peripheral vision and ambulate around the examination room. The patient had FVL on presentation to the time of the patient’s last visit. GVF ⫽ Goldmann visual field; FVL ⫽ functional visual loss.
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