Epidemic optic neuropathy in Cuba. Eye findings
A. A. Sadun, J. F. Martone, R. Muci-Mendoza, L. Reyes, L. DuBois, J. C. Silva, G. Roman and B. Caballero
ORBIS International, New York, NY.
OBJECTIVE: To characterize and establish a clinical definition of the optic
neuropathy that appeared in epidemic form in Cuba in 1992 and 1993.
METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
