Possessing only one eye has made life difficult for Leela, not because she is less able as a cyclops, but because she has received unfair treatment by her peers, and sometimes even superiors, because of it. She has also, on occasion, complained of poor depth perception on account of her one eye.
Leela is probably the most competent character in Futurama. She captains the Planet Express spaceship, and usually saves the members of her crew when they find themselves in trouble.
Her biggest mistake was sleeping with Zapp Brannigan.
See also: Turangalila Symphony