Septo-optic dysplasia (SOD) and optic nerve hypoplasia (ONH) cause congenital visual impairment. Their aetiology is mostly unknown. The authors aim was to investigate the prevalence of specified ophthalmological features in patients with these disorders. These features included impaired visual acuity, nystagmus, strabismus, and relative afferent pupillary defect (RAPD). A retrospective records review was performed on patients with SOD / ONH. There were 102 patients (56 males). The median age at the end of the study was 12.7 years. Best-corrected visual acuity ranged from normal to no light perception. Bilateral ONH was more common than unilateral ONH. Strabismus (85%) and to a lesser extent nystagmus (52%) were both very common in the cohort. Patients with esotropia had worse visual acuity than those who had exotropia. The presence of nystagmus was more likely in cases with bilateral ONH. The authors conclude that patients with SOD / ONH may have normal visual acuity. Many have strabismus, which may cause amblyopia thereby further decreasing visual acuity. Nystagmus occurs commonly and its presence typically indicates bilateral ONH. This work is subject to the limitations of retrospective record review. Future studies to investigate outcomes in a larger cohort of adults with SOD / ONH is important. In addition, more research is needed to quantify the economic cost of this life- long and disabling disorder.