Related Clues:

• It gets capped
• Oculist's piece
• Camera component
• Fisheye ___
• Fish-eye, e.g.
• It helps keep you focused
• Copier part
• Film, in Variety-speak
• Magnifying glass
• Something to see through
• Spectrum maker
• Periscope part
• Eye piece
• It's see-through
• It helps keep one focused