Hypertropia is a type of strabismus (eye misalignment) in which one eye is deviated upward while the other is aligned straight. Alternatively, hypotropia is a type of strabismus in which one eye is deviated downward. A right eye hypertropia can also be known as a left eye hypotropia and vice versa. Causes for vertical misalignment include thyroid eye disease, trauma, and neurological disease. If diplopia (double vision) is present, treatment can include the use of prism in glasses and/or eye muscle surgery.