Possible Clues:

• It limits one's outlook
• Magoo's problem
• Short-sightedness or near-sightedness
• Ophthalmologist's concern
• Lack of foresight
• Mr. Magoo's malady
• Short sight
• PI in Mayo developed eye problem
• It limits one's outlook perhaps all around train crossing river at journey's end
• Eye disorder resulting in near-sightedness