When I tum meoptics

• dumb
• tumble
• my optics: my eyes
• myopic:

• The rhythm of the text is set to the song, "The Shandon Bells", an Irish song (1860) by Francis Sylvester Mahon:
  

With deep affection and recollection,
 I often think of those Shandon bells.
Whose sounds so wild would, in days of childhood,
 Fling round my cradle their magic spells.