The 'snakes' are the lines of collyrium drawn on each lower-lid.
"Vidyapati Bangiya Padabali Songs of the love of Radha and Krishna"
Vidyapati Thakura
The collyrium, the eye salve, may be, will be, painful when it is rubbed into the lids, but it will clear the sight; and the first work of Him, whose dearest name is Comforter, is to convince of sin.
"Expositions of Holy Scripture Genesis, Exodus, Leviticus and Numbers"
Alexander Maclaren
Paulinus of Nola, always beflowered and elegant, wrote to Augustin: "Your letters are a luminous collyrium spread over the eyes of my mind."
"Saint Augustin"
Louis Bertrand