Strabismus - Ocular Misalignment - Differential Diagnosis Algorithm

Phoria:

 • Latent deviation

 • Symmetrical corneal light reflex,

 • Negative cover test positive cover/uncover test

 • Esophoria (eye moves medial -> centre when uncovered)

 • Exophoria (eye moves lateral -> centre when uncovered)

Tropia:

 • Manifest deviation

 • Asymmetrical light reflex,

 • Positive cover test

Non-paretic - Comitant Angle of misalignment unchanged with direction of gaze

 • Accommodative Esotropia (onset 2-4yrs, hyperopic)

 • Congenital Esotropia (contralateral eye deviates medial -> straight when ipsilateral covered)

 • Exotropia (contralateral eye deviates lateral -> straight when ipsilateral covered)

Paretic - Horizontal (eso/exotropia):

 • CN VI problem (eye cannot abduct)

Paretic - Horizontal and/or vertical (Eso/exotropia, hyper/hypotopia, mixed):

 • CN Ill Problem (eye is depressed and abducted, ptosis, large/unreactive pupil)

 • CN IV Problem (eye cannot depress when looking medially)



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