The picture below is the eyelid of an 18 year old boy. He has crusts at the base of his lashes. These crusts are produced from bacteria in the eyelash follicles. This condition is chronic and called blepharitis. It can cause a foreign body sensation, redness, and irritation of the eyes in the mornings. It can be controlled with lid scrubs and occasional antibiotics, but is never eradicated completely.