Disorders• 2 SECTIONNerve Optic Congenital

Congenitally Elevated Optic Disc

Key Facts

•Monocular or binocular congenital crowding of the optic disc with:

•indistinct margins • dome-shaped elevation • absent physiologic cup

•sometimes obvious drusen

•Often confused with acquired optic disc elevation, especially papilledema (hence the term pseudopapilledema)

•Visual field defects may enlarge but visual acuity remains normal

Clinical Findings

•Indistinct optic disc margins, dome-shaped elevation, and absent physiologic cup

•Disc vessels often have excessive tortuosity, trifurcations, or abnormal take-off

•Optic disc drusen may be evident

•Nerve fiber bundle visual field defects may be present

• they may slowly enlarge but do not impair visual acuity

•May be difficult to distinguish from acquired optic disc edema (especially papilledema) on ophthalmoscopic grounds alone

Ancillary Testing

•Red-free fundus photography, B-scan ultrasound, or orbit CT often shows occult optic disc drusen

•Late phase fluorescein angiography shows no dye leakage

Differential Diagnosis

•Papilledema

•Diabetic papillopathy

•Compressive optic neuropathy

•Pre-eruptive anterior ischemic optic neuropathy

Treatment

•None

•Retest visual fields periodically to assess whether defects are present or enlarging to the point of impairing safe driving or other visually demanding occupational tasks

Prognosis

• Visual field loss may become severe but visual acuity remains normal

Fig. 2.1 Congenitally elevated optic discs. Telling the difference between this condition and acquired optic disc elevation, especially papilledema, may be difficult! That is why this condition is often called pseudopapilledema.

Fig. 2.2 Congenitally elevated optic disc with drusen. These refractile particles reflect optic nerve axoplasmic stasis of congenital origin. Visual field loss is often present and may be slowly progressive.

Disc Optic Elevated Congenitally

Disorders• 2 SECTIONNerve Optic Congenital

Optic Disc Coloboma

Key Facts

•Congenital inferotemporal absence of optic disc tissue as the result of faulty closure of fetal fissure

•Retinochoroidal, iris, or eyelid coloboma may also be present

•Corresponding deep, steep-margined, stationary nerve fiber bundle visual field defect

•May have forebrain anomalies, especially basal encephalocele

Clinical Findings

•Fissure-like absence of inferotemporal neuroretinal rim tissue, with distinct margins that may extend beyond the disc margin to involve retinochoroidal tissue

•Iris and lid colobomas sometimes present

•Corresponding steep-margined, non-progressive dense nerve fiber bundle visual field defect

•If papillomacular bundle is involved, acuity may be markedly depressed

•Sometimes forebrain anomalies, especially basal encephalocele

Ancillary Testing

• Brain imaging may show forebrain anomalies

Differential Diagnosis

•Glaucoma

•Chorioretinal scar

Treatment

• Neurosurgery may be indicated to treat basal encephalocele

Prognosis

• Visual field loss is stationary

Fig. 2.4 Optic disc coloboma. Optic disc shows total congenital excavation, the result of incomplete closure of the fetal fissure.

Fig. 2.5 Iris coloboma (arrow) in an eye that also had an optic disc and retinal coloboma in the same region! These are manifestations of the same embryonic defect.

Coloboma Disc Optic