This study evaluated causes, neuroimaging rates and results, and clinical courses of adults presenting to an ophthalmology emergency department with diagnosis of new-onset strabismus. This was a retrospective study of 557 adults (54.8% male) with mean age of 57.3 ±16.7 years (range 18-92). Of these, 40.6% were aged 50-64 years, and 35.4% were ≥65 years if age. Symptoms included diplopia (72.4%), ptosis (6.3%) and eye pain (3.4%). Diagnoses included cranial nerve palsy (66.8%: sixth>third>fourth>mixed), restrictive strabismus (5.4%), stroke (4.7%) and thyroid eye disease (3.1%). Causes included microvascular (48.1%), masses (5%), trauma (4.8%), and idiopathic (12.7%). Neuroimaging findings confirmed lower rates of abnormal findings in microvascular cranial nerve palsies and supports the recommendation for a higher threshold for neuroimaging in acute setting of cranial nerve palsy with suspected microvascular cause.