Hypoplasia of the optic nerve

Hypoplasia of the optic nerve, one-sided or two-sided, is characterized by a reduced amount of nerve fibers. Hypoplasia of the optic nerve can be an isolated anomaly, it can be combined with other developmental defects of the eye or a heterogeneous group of diseases, most often affecting the midline structures of the brain. The specific substances taken by the mother during pregnancy, which may be associated with optic nerve hypoplasia include alcohol, LSD, quinine, protamine cintersulin, steroids, diuretics, cold medicines and anticonvulsants. Upper segmental hypoplasia can be associated with a pregnant woman's diabetes.

[1], [2], [3], [4], [5], [6]

Symptoms of optic nerve hypoplasia

• Visual acuity can vary from normal to blindness.
• The disc is small and gray, surrounded by a yellow halo of hypopigmentation due to concentric chorioretinal atrophy (a symptom of the "double ring"). The outer ring represents what would be the edge of the normal disk.
• The distance from the fovea to the temporal border of the disc often equals or exceeds three disc diameters. This indicates a disk hypoplasia.
• Despite the small disk, the retinal vessels are of normal caliber, but can be tortured.
• In some cases only part of the disk is hypoplastic.

Other manifestations vary considerably depending on the severity and include visual field defects, dyschromatopsia, afferent pupillary defect, foveal hypoplasia, aniridia, microphthalmos. Strabismus and nystagmus in severe bilateral cases. Mild cases can go unnoticed, and a slight decrease in visual acuity can be taken for amblyopia and treated with occlusion.

Systemic manifestations of optic nerve hypoplasia

The de Morsier syndrome (retino-optic dysplasia) occurs in 10% of cases. In addition to bilateral hypoplasia of the optic nerve, it is characterized by malformations of the midline structures of the brain, which can be combined with endocrine disorders. These defects include the absence or dysgenesis of septum pellucidum, thinning or agenesis of corpus caflosum, dysplasia of the anterior third of the ventricle. Often hypopituitarism with low levels of growth hormone, with early diagnosis, the deficit can be adjusted with the continuation of normal growth. This means that the tortuosity of retinal veins in patients with bilateral optic nerve hypoplasia may be a marker of potential endocrine dysfunction.

Frontonasal dysplasia is rare.

Aicardi Syndrome

Syndrome Aicardi is a very rare autosomal dominant X-linked disease, lethal for men in litem. Ocular lesions are usually bilateral, but often asymmetric.

Symptoms

• Pathognomonic are multiple depigmented chorioretinal lacunae grouped around the disk.
• Congenital disc abnormalities include coloboma, hypoplasia, and pigmentation.
• Other eye manifestations: microphthalmus, persistent pupillary membranes, cataracts, iris colobanks.
• Systemic manifestations: infantile spasm, agenesis, corpus callosum, skeletal malformations and psychomotor lag. There may be other serious malformations of the central nervous system, and death usually comes after the first few years of life.

Other anomalies

A variety of rare anomalies of the optic disc, sometimes with concomitant neurologic manifestations.

1. Megalopapilla, in which the horizontal and vertical diameters of the disc are 2.1 mm or more.
2. Parapapillary staphyloma is not a hereditary, usually one-sided state, in which a relatively normal disk is at the base of a deep excavation, the walls of which have dystrophic changes, like the surrounding choroid and retinal pigment epithelium. Visual acuity reduced; can be a local detachment of the retina, sometimes - gonadalozal dysplasia.
3. Dysplasia of the optic disc is a descriptive term for a deformed disc that does not correspond to any diagnostic category.