• Abnormally small optic nerve head
• Congenital decrease optic nerve fibers

Septo Optic Dysplasia - any combination of optic nerve hypoplasia, pituitary gland hypoplasia and midline brain abnormalities

• One of leading causes of childhood blindness
• Incidence
  • Olmstead County, MN- 2.4 per 100,000 children (0-19 years) or 1 in 2287 live births
  • Alaska, 1 per 1000 live births
  • Manitoba Canada- 1 in 1,875 live births or 53.3/100,000 children < 19 years old Paediatr Child Health 2017 Nov;22(8):445
  • Stockholm, Sweden- 17.3/100,000 children < 18 years old Acta Ophthalmol 2014 Sep;92(6):563

• Young maternal age
• First parity
• Maternal smoking
• Preterm birth

• Peripapillary ring- “Double ring sign”
• Small optic nerve
• Thinning of the nerve fiber layer
• Possible tortuosity of retinal vasculature
• Possible persistent grey appearance of the nerve

• Fundus Photography
  • Ratio of Mean Disc Diameter (DD) to Macula-Disc distance (DM)
    • (Horizontal + Vertical Disc Diameter /2) : Distance from center of disc to the center of the macula
    • 
      from Dutton GN. Congenital Disorders of the optic nerve: excavations and hypoplasia. Eye.2004;18:1038-1048
  • OPTOS photographs of 188 adults and children with OHN (108) compared to normals (88)
    • Normal optic nerve horizontal diameter: 1.70 mm (95% CI 1.49, 2.14)
    • Hypoplasia horizontal optic nerve diameter: 1.23 mm (95% CI 0.38, 1.45)
    • Arnold AW et al. Direct OPTOS Nerve Size Determination of Prevalent Optic Nerve Hypoplasia in Alaska. Clinical Ophthalmology 2020;14:491-499
• Optical Coherence Tomography
  • Many commercial devices will attempt to plot the disc diameter and area
  • Use this calculator to estimate the nerve diameter using the Heidelberg OCT machine optic nerve report without the glaucoma upgrade
• MRI

• 11 rare single nucleotide variants were identified in 10 persons (34%) in one 2020 study, including:
  • 2 variants in COL4A1
  • 2 variants in COL4A2
  • 2 variants in CYP26C1
  • 1 variant in each of OPA1 (in a patient who also had a COL4A1 variant), KIF7, SPG7, CYP26A1, and UBE3B
  • 1 copy number variant was identified in SOX5 in 1 patient

See PLoS One 2020;15(2):e0228622

• Brain Anomalies
  • More common
    • Microcephly, absent septum pellucid, posterior pituitary ectopia, migrational anomalies (hypoplasia of corpus callous)
  • Less common
    • porencephaly, schizencephaly, arachnoid cyst, epidermoid cyst
• Pituitary Dysfunction
  • neonatal hypoglycemia
    • associated with neonatal cholestatic jaundice, convulsions and or coma after anesthesia
  • growth hormone deficency
  • diabetes insipidus
• olfactory hypoplasia

• Premature birth- 32%
• Maternal diabetes- 16%
• Bilateral- 84%
• Developmental Delay- 63%
• Neurologic defects- 53%
  • Microcephaly (16%)
  • Cerebral palsy (16%)
  • Corpus callous hypoplasia (11%)
  • Septum Pellucidum aplasia (11%)
  • White matter hypoplasia (11%)
  • Hydrocephalus (11%)
  • Decreased visual acuity- 47%
  • Strabismus- 42%
    • Esotropia 21%
    • Exotropia 21%
  • Endocrine dysfunction- 26%
    • Growth hormone deficiency (16%)
    • Hypothyroid (16%)
    • Diabetes insipidus (11%)
    • Adrenal insufficiency (5%)
    • Hypopituitarism (5%)
    • Precocious puberty (5%)
  • Nystagmus- 26%
  • Refractive error can be myopia, hyperopia and or astigmatism
  • Amblyopia- 11%

• Aicardi Syndrome
• CHARGE Syndrome
• Dominant inheritance
• Prenatal Drug exposure
  • Anticonvulsants
    • Phenytoin (dilantin)
    • Phenobarbital
  • Ethanol
  • Isotretinoin
  • Valproic Acid
• Chromosome abnormalities
  • Distal 5q deletion syndrome
  • Chromsome 1 anomaly- Muscle eye brain disease
  • Partial deletion chromosome 6p
  • Chromosome 7(q22→q34) and 7q32-34 interstitial duplication
  • Chromosome 17 interstitial deletion
• Frontonasal dysplasia
• Goldenhar syndrome
• Idiopathic growth hormone deficiency (ONH seen in 9%)
• Nevus sebaceous of Jadassohn (cutaneous, possibly malignant, phacomatosis)
• Maternal Diabetes
• Orbital hemangioma
• Periventricular leukomalacia
• Suprasellar teratoma

• Mohoney BG et al. Incidence and Associated Endocrine and Neurologic Abnormalities of Optic Nerve Hypoplasia. JAMA Ophthalmol. 2013:131(7)898-902.
• Dutton GN. Disorders of the optic nerve: excavations and hypoplasia.Eye 2004;18:1038-1048
• Arnold AW et al. Direct OPTOS Nerve Size Determination of Prevalent Optic Nerve Hypoplasia in Alaska. Clinical Ophthalmology 2020;14:491-499
• Pang Y. et al. Comparison of Heidelberg Retina Tomograph with disc macula distance to disc diameter ratio in diagnosing optic nerve hypoplasia
• Hellström A. et al. The Clinical and Morphologic Spectrum of Optic Nerve Hypoplasia. JAAPOS 1999;3(4):212-20