A six-month old boy is referred for nystagmus, poor vision and sluggish pupil reactivity. There are a number of options: electroretinogram (ERG), gene testing for Leber’s congenital amaurosis (LCA), gene testing for achromatopsia, or MRI of the brain. However, due to the child’s classic presentation of LCA, Dr. Arlene Drack chooses gene testing and discusses her decision.