Absence of the optic chiasm
Also known as: Optic chiasm aplasia · Aplasia of the optic chiasm · Congenital absence of the optic chiasm · Chiasma opticum-Aplasie · Agenesie des Chiasma opticum · …
Overview
What it is
This is a rare congenital brain malformation where the optic chiasm—the structure where nerve fibers from each eye cross over to the opposite side of the brain—fails to develop. Without this connection, the visual pathways from the eyes to the brain's visual cortex are disrupted. This condition is notably documented in Belgian Sheepdogs as a form of congenital achiasma.
How it presents
Symptoms are present from birth and typically become noticeable to owners as soon as the puppy's eyes open. Affected puppies show signs of visual impairment or complete blindness, often accompanied by involuntary, rapid eye movements and misaligned eyes.
Treatment
This congenital condition is incurable, and there is no surgical or medical treatment available to restore normal vision. Management focuses on supporting the dog in a safe, stable environment, with initial diagnostic costs typically ranging from 500 to 2000 EUR.
How it's tested
Affected breeds
Treatment cost
Estimated range of typical treatment cost. Actual cost depends on severity, clinic and region.
Frequently asked
What is Absence of the optic chiasm?
This is a rare congenital brain malformation where the optic chiasm—the structure where nerve fibers from each eye cross over to the opposite side of the brain—fails to develop. Without this connection, the visual pathways from the eyes to the brain's visual cortex are disrupted. This condition is notably documented in Belgian Sheepdogs as a form of congenital achiasma.
How is Absence of the optic chiasm tested?
Various clinical and genetic tests are used depending on the breed and presentation.
Which breeds are most affected?
This condition isn't tied to a specific breed in our database.