Congenital optic nerve dysplasia

We all know that there is a disease in life called congenital visual neuroplasia. This kind of dysplasia usually manifests itself in the baby when he is young. If mothers observe carefully, they will easily find that there are some differences in the baby’s vision. In fact, this will have a great impact on the baby’s future, so the baby should be treated in time when it is just discovered. So what are the manifestations of congenital visual dysplasia?

Optic nerve hypoplasia is often a defect located at the entrance of the optic nerve, manifested as partial or complete loss of the optic disc. If the optic nerve does not develop at all, it is called optic nerve anomaly. In eyes with optic nerve hypoplasia, the retinal nerve fiber layer becomes thinner or absent, and the number of ganglion cells decreases or disappears. It is generally believed that the disease is caused by a differentiation disorder of the retinal ganglion cell layer during embryonic development.

Causes

Optic nerve hypoplasia may cause growth stagnation or abnormal development due to some reasons during the development process from the initial embryonic stage and organogenesis stage of the fetal period to the end of the third month. Optic nerve dysplasia is a non-progressive congenital abnormality of fundus development caused by impaired differentiation of retinal ganglia during embryonic development of 13 to 17 mm. If the germinal fissure has closed before the development of optic ganglion cells, the paraxial mesoderm tissue cannot enter the germinal fissure, resulting in optic nerve underdevelopment. It is clinically divided into two types. The first type is optic disc coloboma combined with retinal and choroidal coloboma, and the second type is located entirely within the optic nerve sheath, which is a true optic disc coloboma. Patients with choroidal coloboma also have dysplasia of the mesodermal tissue around the primitive optic vesicle.

The specific cause of optic nerve dysplasia and hypoplasia is unknown. A few are dominantly inherited, and most may be related to the effects of drugs or infectious diseases in the early stages of maternal pregnancy. The use of phenytoin, quinine, etc. during pregnancy or infection with syphilis, rubella, and cytomegalovirus can all cause it.

prevention

There is currently no clear preventive measure for this disease, but considering its possible causes, conducting pedigree analysis on the families of patients with the disease and avoiding the birth of high-risk offspring based on genetic laws; as well as avoiding the use of drugs such as phenytoin sodium, quinine, or infection with syphilis, rubella, cytomegalovirus, etc. during pregnancy may be of certain significance in reducing the occurrence of the disease.

History and examination

Key diagnostic factors

1. Fundus (common)

The optic disc is partially or completely hypoplastic and is smaller than normal, about 1/3 to 1/2 the size of a normal optic disc. It is grayish white and may be surrounded by a yellow halo, that is, the retinal pigment epithelium crosses the outer edge of the scleral lamina to form a double ring sign (Figure 1). The black inner ring originates from the thickened retinal pigment epithelium and is connected to the underdeveloped optic nerve. The outer ring originates from the junction of the scleral cribriform plate and the sclera, forming an unclear and irregular bright white ring around the optic disc, which is exposed sclera or proliferative fibrous tissue. In most cases, the optic disc has an irregular funnel-shaped depression. The smaller ones are confined to the optic nerve sheath, similar to the large physiological depression. The larger ones can be as deep as 7 to 10 mm, or accompanied by a retrobulbar cyst. The deepest part of the depression is often located below or slightly to one side. The bottom of the depression is smooth, and the gray-white spots of the cribriform plate are not visible.