Abnormal Eye Movements in a Young Girl

A 5-year-old girl was referred for nystagmus with a history of esophageal atresia, small bowel obstruction, mild cognitive impairment, low tone, and increased reflexes. Alternating vertical and torsional nystagmus was noted. What would you do next?
Source: JAMA Ophthalmology - Category: Opthalmology Source Type: research