Strabismus describes a misalignment of the eyes where they do not point in the same direction. Types are classified by direction of deviation, constancy, and underlying cause.
By Direction
Esotropia is an inward turn, exotropia an outward turn, hypertropia an upward deviation, and hypotropia a downward deviation. Some patients have combinations or vertical and torsional components.
- Concomitant strabismus shows similar angle in all gaze directions
- Incomitant strabismus varies with gaze and often reflects muscle or nerve palsy
- Intermittent deviations may appear with tiredness or inattention
- Constant deviations carry higher amblyopia risk in children
By Onset and Cause
Infantile and childhood strabismus often relate to refractive errors or imbalance among extraocular muscles. Adult strabismus may arise from decompensated childhood deviations, cranial nerve palsies, trauma, or thyroid eye disease.
- Accommodative esotropia improves when long‑sight is corrected with glasses
- Paralytic strabismus causes double vision and limited eye movements
- Management includes glasses, prisms, exercises, and surgery
- Early assessment in children helps prevent amblyopia and supports binocular development
