NBEO Ocular Motility Practice Test

Duane retraction syndrome in Type I shows a clear pattern: the eye cannot move outward well, so abduction is limited, while inward movement (adduction) is relatively preserved. This happens because the lateral rectus is not properly innervated, often due to a malformed or absent abducens nerve, so outward movement is diminished. When the eye is asked to look inward, co-contraction of the medial rectus with the misinnervated lateral rectus can pull the globe back into the orbit, causing globe retraction and a narrowing of the palpebral fissure. That combination—restricted abduction with preserved adduction and characteristic globe retraction on adduction—defines Type I. The other patterns fit Type II (adduction limited) or Type III (both directions limited), while no restriction would be normal motility.