hair like worms on lettuce
They are at the top of the lettuce waving around as if they are hoping to be picked up by birds. Could they be parasites. They don't appear to be nematodes. Appearance is white and so thin and are 4 to 5 inches.
Is it possible for you to send us a digital photo or two? They can be attached to this reply.
There is a hair-like worm called gordian worms (horsehair worms) which are only parasitic to invertibrates like grasshoppers, but are harmless to humans.
We can't be sure unless you can send us photos.