Congenital Optic Disc Anomalies: Hypoplasia, Coloboma, Morning Glory, Optic Pit and More

Last updated: November 2026

Congenital disc anomalies matter for three reasons: they can cause poor vision and nystagmus in children, they are linked to brain, endocrine and kidney problems that need investigation, and several of them mimic acquired disease such as papilloedema, glaucoma or a chiasmal lesion. Each has a recognisable look, and most have one complication or association that examiners always ask about.

Optic nerve hypoplasia

• A small disc with fewer axons; vision ranges from normal to no light perception. Bilateral cases present with nystagmus and poor visual behaviour; unilateral cases with strabismus.
• Double-ring sign: a pale or pigmented ring around the small disc, marking where the normal-sized scleral canal would end.
• A useful measure: the ratio of the disc-to-fovea distance to the disc diameter. A ratio over about 3 suggests hypoplasia.
• Associations: maternal diabetes, young maternal age, alcohol and drug use in pregnancy.
• Septo-optic dysplasia (de Morsier syndrome): optic nerve hypoplasia with absent septum pellucidum and/or pituitary deficiency. Every child with bilateral (and many with unilateral) hypoplasia needs an MRI of the brain and endocrine assessment. Cortisol and growth hormone deficiency can cause hypoglycaemia, poor growth and even sudden death during illness; posterior pituitary ectopia on MRI predicts endocrine problems.
• Superior segmental hypoplasia ("topless disc") is linked to maternal diabetes and causes inferior field defects.

Optic disc coloboma

• Failure of the embryonic (choroidal) fissure to close, so the defect is inferior: a white, sharply outlined excavation of the inferior disc, often continuous with a retinochoroidal coloboma and an iris coloboma (keyhole pupil).
• Can be bilateral and associated with microphthalmos and systemic syndromes: CHARGE (coloboma, heart defects, choanal atresia, retarded growth, genital and ear anomalies; CHD7 gene), and the papillorenal (renal-coloboma) syndrome (PAX2) with kidney hypoplasia. Check the kidneys and hearing.
• Complications: rhegmatogenous retinal detachment from breaks at the edge of a retinochoroidal coloboma (often needs vitrectomy and silicone oil), serous detachment, and choroidal neovascularisation at the margin.

Morning glory disc anomaly

• A large, funnel-shaped excavation of the disc and surrounding retina with a central white glial tuft, a ring of pigment, and many straight vessels radiating outward like spokes (resembling the morning glory flower). Usually unilateral, more common in girls, with poor vision.
• Associations: transsphenoidal basal encephalocele (midline facial defects such as hypertelorism, cleft lip or palate), pituitary problems, and moyamoya disease and other cerebrovascular anomalies (PHACE syndrome). Arrange MRI with MR angiography.
• Serous retinal detachment develops in about a quarter to a third of eyes. The disc can appear to contract and dilate.

Optic disc pit

• A small, round or oval, grey, yellow or white depression in the disc, usually inferotemporal (about two-thirds temporal); usually unilateral. Vision is normal unless the macula is involved; there may be an arcuate field defect.
• Optic pit maculopathy develops in roughly a third to a half of eyes, typically in the third or fourth decade: fluid (from the vitreous or cerebrospinal fluid) passes through the pit into the retina, first causing a schisis-like separation of the inner retina and then an outer layer (serous) macular detachment. OCT shows the connection with the pit.
• Management: observe if vision is good (some resolve); vitrectomy with posterior vitreous detachment, gas tamponade, with or without internal limiting membrane peeling or an inverted flap, and juxtapapillary laser are used for persistent detachment with falling vision.

Tilted disc syndrome

• The disc is oval and tilted, with the long axis oblique and the inferonasal part set back, situs inversus of the vessels (they exit nasally before turning temporally), an inferonasal crescent and thin fundus.
• Usually bilateral, with myopic astigmatism.
• Superotemporal field defects that can look bitemporal, but they do not respect the vertical midline and often improve with refractive correction. This is the classic mimic of a chiasmal lesion; an MRI is needed only if the defect does respect the midline or other signs are present.

Myelinated (medullated) retinal nerve fibres

• White, feathery patches with frayed edges following the nerve fibre layer, usually next to the disc; seen in about 1% of people. Myelination normally stops at the lamina cribrosa.
• Usually harmless, causing only a matching scotoma. Large unilateral patches can come with high axial myopia and dense amblyopia (Straatsma syndrome), so check the refraction and treat amblyopia early.
• Do not mistake it for cotton wool spots or papilloedema: cotton wool spots are small and fluffy, without the feathery edge.

Optic disc drusen

• Calcified deposits within the optic nerve head, buried in childhood and becoming visible (refractile yellow bodies) with age; often bilateral and familial. Discs are small and crowded, without a cup.
• The main issue is pseudopapilloedema: elevated disc margins without true swelling. Clues: no venous congestion or obscuration of vessels at the margin, anomalous vessel branching, normal spontaneous venous pulsation.
• Diagnosis: B-scan (bright, persistent at low gain, with shadowing), fundus autofluorescence (bright for exposed drusen), EDI-OCT (hyporeflective ovoid bodies with a hyperreflective margin; the preferred test for buried drusen), and CT (calcification).
• Field defects (enlarged blind spot, arcuate or nasal step) develop in many adults and progress slowly; associated with NAION, vascular occlusions and peripapillary CNV. See papilloedema vs pseudopapilloedema.

Other anomalies to recognise

Summary table for exams

Test yourself: flip cards

Quick quiz

Related: Papilloedema vs Pseudopapilloedema, Optic Disc Oedema Evaluation Flowchart, Leukocoria: A Differential, Paediatric Ophthalmology Notes: ROP, Leukocoria, PCG, Visual Pathway and Field Defects Made Easy: Five Rules.

Key sources

• American Academy of Ophthalmology. Basic and Clinical Science Course, Section 5: Neuro-Ophthalmology; Section 6: Pediatric Ophthalmology and Strabismus (current editions)
• Brodsky MC. Congenital optic disk anomalies. Surv Ophthalmol. 1994;39:89-112
• Malmqvist L, et al. The Optic Disc Drusen Studies Consortium recommendations for diagnosis of optic disc drusen using optical coherence tomography. J Neuroophthalmol. 2018