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Optic Nerve Hypoplasia
- 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
Epidemology
- One of leading causes of childhood blindness
- Incidence
- Olmstead County, MN is 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
Risk Factors
- Young maternal age
- First parity
- Maternal smoking
- Preterm birth
Diagnosis
Clinical Features
- 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
Optic Nerve Measurements
- 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)
- Optical Coherence Tomography
- Many commercial devices will attempt to plot the disc diameter and area
- MRI
Associated Findings
- 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
In Olmstead County, MD population
- 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%
Associated Disorders
- Dominant inheritance
- Prenatal Drug exposure
- Anticonvulsants
- Ethanol
- 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
- Idiopathic growth hormone deficiency (ONH seen in 9%)
- Nevus sebaceous of Jadassohn (cutaneous, possibly malignant, phacomatosis)
- Maternal Diabetes
- Orbital hemangioma
- Periventricular leukomalacia
- Suprasellar teratoma