of Disc+Horizontal diameter of Disc) divided by 2. The distance between the center of the disc and the macula is DM. Interpretation: When the ratio of DM to DD is greater than 3, ONH is suspected, and when it is greater than 4, Optic Nerve Hypoplasia is definite. Treatment There is no cure for ONH; however, many therapeutic interventions exist for the care of its symptoms. These may include hormone therapy for hypopituitarism, occupational, physical, and/or speech therapy for other issues, and services of a teacher for students with blindness/visually impairment. Special attention should be paid to early development of oral motor skills and acclimation to textured foods for children with texture aversion, or who are otherwise resistant to eating. Sleep dysfunction can be ameliorated using melatonin in the evening in order to adjust a child's circadian clock. Treatment for strabismus may include patching of the better eye, which may result in improved vision in the worse eye; however, this should be reserved for cases in which the potential for vision improvement in both eyes is felt to be good. Surgery to align the eyes can be performed once children with strabismus develop equal visual acuity in both eyes, most often after the age of three. Generally surgery results in improved appearance only and not in improved visual function. Prognosis The visual prognosis in optic nerve hypoplasia is quite variable. Occasionally, optic nerve hypoplasia may be compatible with near-normal vision; in other cases, one or both eyes may be functionally, or legally blind. Although most patients with only optic nerve involvement lead normally productive lives, those with accompanying endocrine dysfunction or other midline cerebral abnormalities are more at risk for on-going intellectual and other disabilities. Epidemiology Optic nerve hypoplasia (ONH) is a congenital condition in which the optic nerve is underdeveloped (small). Many times, de Morsier’s Syndrome or septo-optic dysplasia (SOD) is associated with ONH, however, it is possible to have ONH without any additional issues like SOD. SOD is a condition that can involve multiple problems in the midline structures of the brain, stemming from miswiring of the brain and central nervous system. Besides having small optic nerves, persons with ONH can have agenesis of the corpus callosum, absence of the septum pellucidum, maldevelopment of the anterior and posterior pituitary gland, and anomalies of the hypothalamus. Because of this, all children with ONH are at risk for developmental delays