Possible Clues:

• Feel something of a blow to experience second sight thus?
• Identify large drink — and be affected by it?
• One c.c. of this and you're tight, by the look of it
• What you'll do if you get tight with even a c.c. of this, by the sound of it
• Sounds as if there's a c.c. of this for the eye
• Visit twins?
• Contemplate a large drink - or two!
• Have 8/22 vision?
• Observe two of everything
• Understand whisky perhaps could make one this