Cuban Epidemic Optic Neuropathy Research Articles

Treatment and Outcomes in Nutritional Optic Neuropathy.

Nutritional optic neuropathy is a potential cause of severe visual loss; however, appropriate and timely management can result in excellent visual outcomes. The purpose of this review is to outline our current understanding of the treatment and outcomes for nutritional optic neuropathy. Current understanding of nutritional optic neuropathy has been greatly aided by some well-reported and investigated epidemics of the condition, most notably the Cuban epidemic optic neuropathy of the early 1990s. More recently, there is an emerging literature surrounding nutritional deficiencies that can occur in patients who have undergone bariatric surgery. There also continues to be a stream of case reports in the literature that add to our understanding. Nutritional optic neuropathy has a great deal of overlap with toxic optic neuropathies and hereditary optic neuropathies and should not be thought of in isolation from these conditions. The mainstay of treatment for nutritional optic neuropathy involves identifying and replacing deficient nutrients as well as identifying and eliminating contributory toxins. It is also important to identify contributory genetic factors and to consider the broader social, economic and societal factors which may contribute.

Cuban Epidemic Optic Neuropathy (1991-1993) and José Saramago's Novel Blindness (1995)

This article reviews the history of Cuban epidemic optic neuropathy (1991-1993), which caused visual loss, peripheral neuralgias, and other neurologic symptoms in over 50,000 persons, an incidence of almost 0.5% of the entire population. The clinical findings, etiology, and treatment are described. We then relate the Cuban epidemic to the fictional epidemic of contagious blindness depicted by Nobel Laureate José Saramago in his 1995 novel Blindness. This novel describes an unnamed modern city in which all inhabitants, except the ophthalmologist's wife, are affected with a white, not black, blindness. Historical review and literary essay. The sources for the Cuban epidemic were an extensive review of the published literature and personal communications with physicians who treated these patients. Both authors have analyzed the novel and the critical literature about Saramago's writings. Though Saramago uses the epidemic of blindness as an allegory to comment on human weakness and immorality, he may also have known of the actual Cuban epidemic. Saramago was a lifelong member of the Communist party, as well as a friend of Fidel Castro and admirer of the Cuban government. We have no proof that Blindness was influenced by the Cuban epidemic, but we find it plausible. It is valuable to examine the real and fictional epidemics side by side, not least because Saramago's novel depicts the actions of an ophthalmologist during an epidemic of blindness. Ophthalmologists may be interested in a novel that uses the language of eyes, vision, sight, and blindness extensively.

Optical Coherence Tomographic Comparison of Cuban Epidemic and Leber’s Hereditary Optic Neuropathy

Following the epidemic of optic and peripheral neuropathy, which occurred in Cuba between 1991 and 1993, a number of patients have been re-evaluated, including testing with optical coherence tomography (OCT) and electrophysiology. At the same time, a number of patients with Leber’s hereditary optic neuropathy have also been evaluated. The purpose of this study was to detect residual loss of retinal nerve fibre layer (RNFL) in patients who suffered Cuban epidemic optic neuropathy (CEON), and to compare these findings with those in patients with Leber’s hereditary optic neuropathy (LHON). Optical coherence tomography as well as clinical examinations were performed on 11 patients diagnosed with CEON 15 years following the epidemic and 14 patients with LHON. OCT in CEON patients showed thinning of the RNFL in the temporal sector and normal thickness in other quadrants. However, patients with chronic LHON had more diffuse RNFL loss throughout the retina. OCT findings corresponded with clinical findings in CEON and LHON. There was drop out of the papillomacular bundle in both diseases. Two patients in the acute stages of LHON and three LHON carriers showed thinning of the temporal RNFL only. This is the first report of OCT in CEON that shows residual damage in the papillomacular bundle compared with chronic LHON where there is more diffuse and progressive loss of the RNFL. The importance of OCT for the diagnosis and evaluation of similar optic neuropathies is emphasised.

Cuban Epidemic Optic Neuropathy and its Relationship to Toxic and Hereditary Optic Neuropathy

The similarities and differences between toxic/nutritional and hereditary optic neuropathy and the pathophysiologic mechanisms that they have in common are described. This is based on data from the epidemic suffered in Cuba in 1992, which affected the optic nerves of many individuals and the experience of the authors in dealing with various toxic optic neuropathies, as well as Leber’s hereditary optic neuropathy.

Reply to the Letter to the Editor ‘Cuban Epidemic Optic Neuropathy (CEON) and actual methods to measure immune response in central nervous system’

Reply to the Letter to the Editor ‘Cuban Epidemic Optic Neuropathy (CEON) and actual methods to measure immune response in central nervous system’

Cuban epidemic optic neuropathy (CEOP) and actual methods to measure immune response in CNS

Cuban epidemic optic neuropathy (CEOP) and actual methods to measure immune response in CNS

Brain barrier dysfunction in Cuban Epidemic Optic Neuropathy

There are practically no references to cerebrospinal fluid (CSF) studies in tropical or nutritional neuropathies. In the present paper we present the results of CSF studies in patients with Cuban Epidemic Optic Neuropathy (CEON) during epidemic and endemic periods, with an appraisal as to the contribution of brain barriers' function in the pathophysiology of this disease. Two hundred and five patients with CEON were studied during the epidemic period (1992-1993) and 12 patients outside the outbreak (1995-1997). CSF protein determination and electrophoresis were carried out, as well as serum and CSF albumin and immunoglobulin G (IgG) quantitation for calculating IgG and Q(alb) indexes, in order to evaluate intrathecal IgG synthesis and the permeability of the blood-CSF barrier (B-CSF B). One fourth of the patients had increased permeability of the B-CSF B, but damage was more frequent between 16 and 60 days from onset of disease, disappearing after 120 days. B-CSF B dysfunction was more prevalent in patients with severe neurological impairment, although it was not related to the severity of ophthalmological damage. The group of patients studied outside of the outbreak (endemic period) showed similar results. The possible association of increased permeability of the B-CSF B with oxidative stress, which lies on the basis of this epidemic outbreak, is discussed.

Optic Neuropathies for the Neurologist

Before embarking on expensive ancillary testing, it is crucial for the neurologist to distinguish visual loss due to optic nerve dysfunction from other causes of visual loss. This can usually be accomplished based on specific features of the history and bedside examination. Once it has been established that a patient has some form of optic neuropathy, several clinical features are helpful in determining the etiology. The most important of these is the time course. Other factors include presence or absence of pain, pattern of visual loss (particularly visual field defects), and funduscopic appearance. In most cases, by using this information it is possible to differentiate among the common forms of optic neuropathy: papilledema, ischemic optic neuropathy, optic neuritis, compressive lesions, toxic/nutritional deficiencies, and hereditary forms. This article also reviews recent information concerning the evaluation and treatment of optic neuritis, how to recognize conditions that mimic optic neuritis (e.g., neuroretinitis, papillophlebitis), distinguishing arteritic from non-arteritic AION, and new developments in the genetics of Leber's Hereditary Optic Neuropathy. There is also a discussion of various forms of toxic/nutritional visual loss including Cuban Epidemic Optic Neuropathy and visual loss due to commonly prescribed medications.

The optic nerve

Recent articles in the scientific literature have described major advances in our understanding of the anatomy and vascular relationships of the optic nerve (cranial nerve II) and of the diagnosis and treatment of a variety of disorders affecting this nerve, including congenital anomalies of the optic disc, dominant hereditary optic neuropathy, anterior and retrobulbar arteritic and nonarteritic ischemic optic neuropathy, optic neuritis, Cuban epidemic optic neuropathy, toxic and nutritional optic neuropathies, radiation-induced optic neuropathy, AIDS-related optic neuropathy, optic neuropathies caused by tumors, and papilledema.

Cuban Epidemic Optic Neuropathy Mitochondrial DNA Analysis

To search for mitochondrial DNA (mtDNA) mutations previously associated with Leber's hereditary optic neuropathy (LHON) in patients with an optic neuropathy that appeared in epidemic form in Cuba. Twelve Cuban patients underwent a comprehensive neuro-ophthalmologic examination and were found to have a characteristic optic neuropathy, Cuban epidemic optic neuropathy (CEON). At the same time, one patient was diagnosed with typical LHON that occurred during the epidemic. Blood samples were taken from these patients as well as from 3 controls with normal neuro-ophthalmologic examinations. These samples were blindly analyzed for 9 LHON-associated mtDNA mutations by molecular genetic methods. CEON bore clinical and epidemiological similarity to LHON, however, family histories, systemic symptoms (especially weight loss and polyuria), and symptoms of peripheral neuropathy permitted a clinical distinction. None of the 12 patients with CEON or 3 controls had any of the LHON-associated mtDNA mutations. Only the patient with clinical LHON, who did not meet the case definition for CEON, harbored the 11778 mtDNA mutation. Known mtDNA mutations are not found frequently in CEON patients but they may contribute to some cases of Cuban optic neuropathy. CEON may represent an acquired variety of mitochondrial dysfunction induced by nutritional deficiencies, toxins, or both. Alternatively, CEON patients may also harbor as yet undiscovered mtDNA mutations that contribute to their genetic susceptibility.

Epidemic Optic Neuropathy in Cuba

To characterize and establish a clinical definition of the optic neuropathy that appeared in epidemic form in Cuba in 1992 and 1993. At the invitation of the Cuban Ministry of Health, Havana, members of ORBIS International and the Pan American Health Organization, assembled teams that traveled to Cuba in May 1993. We were initially briefed by Cuban national experts in the areas of virology, nutrition, toxicology, ophthalmology, neurology, and public health. We then examined 20 patients on our own. Thirteen of these patients underwent a comprehensive neuro-ophthalmologic examination, including neurologic examination, ophthalmologic examination, visual fields, optic nerve function studies, contrast sensitivity studies, and funduscopy. We returned 4 months later to perform an additional 12 comprehensive neuro-ophthalmologic and follow-up examinations. Only seven of the 13 patients who were alleged to have the optic form of the epidemic and who were rigorously and systematically examined on the first visit demonstrated a bilateral optic neuropathy. These seven patients had several features that included decreased visual acuity, poor color vision, central scotomas, decreased contrast sensitivity, saccadic eye movements, and most prominent and distinctive of all, nerve fiber layer wedge defects of the papillomacular bundle. Our clinical definition was then implemented by the Cuban ophthalmologists and epidemiologists. On returning 4 months later, we found that all newly presented patients were correctly diagnosed to have the epidemic disease. With the new case definition and the application of a few simple psychophysical tests, the false-positive rate of diagnosis became much lower. After vitamin therapy, we reexamined the patients seen on our initial visit, and all showed marked improvement. The Cuban epidemic was characterized by an optic neuropathy with features that were similar to those of tobacco/alcohol amblyopia and Leber's optic atrophy. Recent political, economic, and social changes in Cuba may have contributed to the nutritional and/or toxic compromise of mitochondrial function of an acquired nature, which led to selective retinal ganglion cell damage. We have termed this condition Cuban epidemic optic neuropathy.