Congenital achiasma

Congenital achiasma is an extremely rare condition present from birth in which the optic chiasm — the point where the two optic nerves partially cross over in the brain — fails to form properly. Normally, nerve fibers from each eye cross at the optic chiasm so that visual information from both eyes is shared between the two sides of the brain. In congenital achiasma, this crossing does not happen, meaning that each side of the brain only receives signals from the eye on the same side. This abnormal wiring leads to problems with how the brain processes visual information, particularly affecting depth perception and binocular vision. People with this condition often develop a distinctive type of involuntary eye movement called seesaw nystagmus, where one eye moves up while the other moves down in a rocking pattern. They may also have reduced visual acuity and difficulty with stereoscopic (3D) vision. Some individuals may not notice significant problems in daily life, while others may have more noticeable visual difficulties. Congenital achiasma can occur on its own (isolated) or alongside other developmental brain abnormalities. There is currently no cure or surgical fix for the underlying miswiring. Treatment focuses on managing symptoms such as nystagmus and optimizing vision through corrective lenses, low-vision aids, and supportive therapies.

Bring these to your next appointment

• Q1.How severe is the achiasma, and are there any other brain abnormalities present?,What level of vision can we expect, and is it likely to change over time?,Are there any treatments or therapies that could help reduce the nystagmus?,Should genetic testing be done to look for an underlying cause?,What school accommodations should we request for our child?,How often should follow-up eye and brain imaging exams be scheduled?,Are there any activities or situations we should avoid due to reduced depth perception?

Common questions about Congenital achiasma