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46-year-old gentleman with bilateral blurry vision and photophobia for 6 months.
Digital Journal of Ophthalmology 2004
Volume 10, Number 4
February 3, 2004
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| Diagnosis and Discussion | Tobacco Amblyopia typically occurs in patients who are pipe and cigar smokers and the etiology is unknown. There has been a marked decline in the incidence of Tobacco Amblyopia since the advent of genetic testing for Leber hereditary optic neuropathy as it was felt that many patients were initially misdiagnosed. There is a large differential in patients with bilateral ceco-central scotomas including nutritional optic neuropathy (B12 deficiency), Leber's hereditary optic neuropathy, Kjers dominant optic atrophy, cilioretinal artery occlusion, infectious optic neuropathy such in syphilis, and psychogenic loss.
A multifactoral etiology is postulated since only a minority of patients who smoke develop this disease and no dose dependent correlation has been discovered. Cyanide toxicity from cigarette smoke and relative malabsorption of Vitamin B12 from the gut have been postulated as mechanisms, but not proven (1). Alcohol has also been postulated to be a co-factor in this disease process, however, alcohol alone has not been proven to be toxic to the visual pathways. Low serum vitamin B12 levels have been suspected as one factor (2).
Patient with Tobacco Amblyopia can have any level of visual acuity. It presents as a painless, progressive bilateral optic neuropathy with visual loss, dyschromatopsia, and ceco-central scotomas on visual field testing. Nystagmus, ptosis, and ophthalmoplegia can be present if the patient is experiencing Wernicke's encephalopathy. The optic nerve appears pale and the rest of the fundus usually appears normal. An evanescent peripapillary retinopathy characterized by hemorrhages and dilated, tortuous vessels in the nerve fiber layer has been described in a case series (3).
Treatment consists of hydroxocobalomin injections or oral replacement therapy and cessation of smoking. Nonetheless, patients such as the one presented here who have continued to smoke and who receive vitamin B12 do improve. Previous studies have shown that hydroxocobalomin is superior to cobalomin alone in the treatment of these patients. Administration of the medications with an internist and close follow up with visual field testing is recommended when following these patients. | |
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