[i]Atropa Belladonna[/i], or deadly nightshade, is a relatively common plant in much of the Eastern hemisphere. One of its more notable characteristics is that it contains several potent neurotoxins which inhibit nerve activity. Too much of this toxin will slow, paralyze, and ultimately kill once the toxin reaches and stops the heart or diaphragm. The species name [i]belladonna[/i], or pretty woman in Italian, refers to this toxin's use as a cosmetic, especially among women in renaissance-era Italy (think Ezio). The toxin was added in drops to the eyes, where the nerve inhibition relaxed the muscles in the eye, resulting in pupil dilation. This was considered attractive (apparently) but also meant that the women in question were overexposed to light, blurring their vision considerably. Habitual use was reported to cause blindness. TL;DR: Rich Italian women used to squirt poison juice into their eyes to look nice, partially blinding themselves in the process. The more you know, right?