Definition: Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
Input: Abstract: Bilateral optic atrophy is reported in two patients who, although they were long-standing users of the leaves of Catha edulis, had chewed larger quantities than usual. Since the leaves of this plant are used widely throughout its native area as the source of a mildly stimulant narcotic, the effect in these cases may be an idiosyncratic reaction to an unusually large dose.

The presumed neurotoxic effects of Catha edulis--an exotic plant now available in the United Kingdom.