Amblyopia is a decreased visual acuity without organic lesion.
Proposed mechanisms:
(1) increased cyanide levels associated with smoking
(2) variable vitamin deficiencies associated with alcohol abuse
Clinical features:
(1) history of tobacco use with or without ethanol abuse
(2) bilateral visual field loss with central scotoma
(3) occasionally pallor of the optic disc
(4) variable paresthesias and dysethesias
(5) exclusion of other explanations
(6) slow improvement if tobacco and alcohol are stopped and/or vitamin deficiencies are treated
Differential diagnosis:
(1) hypoxic or ischemic injury
(2) methanol intoxication
(3) pernicious anemia with retrobulbar neuritis
(4) ethambutol therapy
(5) multiple sclerosis
