What causes difficulties in reading small print and color recognition?

Difficulties in reading small print and color discrimination are most often seen in the early stages of alcoholic amblyopia, an initial condition that typically progresses over days to weeks to a loss of visual sensitivity in both eyes, seen in chronic alcoholics, and is a specific visual impairment seen in patients with chronic alcoholism. The disease is a lesion of retrobulbar optic neuritis with involvement of macular optic disc fibers. Pathology reveals symmetrical myelin loss of the central fibers of the optic nerve on both sides and loss of retinal ganglion cells, and is more severe in the macula, and in severe cases the optic nerve fibers may be replaced by collagenous connective tissue. Progressive vision loss or blurred vision is the main manifestation of this disease. The vision loss may progress gradually over weeks to months. Initial symptoms in patients are difficulty reading small print and discriminating colors, which gradually progresses to decreased visual sensitivity and blurred vision over days to weeks and usually does not progress to total blindness, although some patients progress rapidly and suddenly develop total blindness after a single episode of heavy alcohol consumption. The vision loss may be unilateral or may involve both eyes. Wearing glasses does not improve vision. Both eyes often have a central dark spot in the visual field, mostly symmetrical, and the dark spot is more prominent in the red-green than in the white field. The peripheral visual field is usually not involved, and the patient has difficulty distinguishing between red and green colors. The fundus examination can be completely normal, but in longer term cases, temporal pallor of the optic disc or atrophy of the optic disc can also be seen. The pathogenesis of this disease, which is associated with long-term alcohol consumption, is not fully understood. Some reports suggest that it is mainly caused by nutritional deficiencies, especially B vitamin deficiencies. It is also associated with optic nerve damage caused by the direct toxic effects of alcohol. The pathological changes can be seen as symmetrical myelin loss of the central fibers of the optic nerve on both sides and the disappearance of retinal ganglion cells, which are heavier in the macula area, and in severe cases the optic nerve fibers can be replaced by collagenous connective tissue.