Certified Ophthalmic Assistant Practice Exam

What is the name of the point where half the nerve fibers from each eye cross to the opposite side?

1. Optic bulb

2. Optic disc

3. Optic chiasm

4. Optic tract

The correct answer is: Optic chiasm

The point where half the nerve fibers from each eye cross to the opposite side is called the optic chiasm. This structure is critical in the visual pathway as it allows for the integration of visual information from both eyes, facilitating binocular vision and depth perception. At the optic chiasm, the fibers from the nasal (inner) retina of each eye cross over to the opposite side, while the fibers from the temporal (outer) retina continue to the same side. This crossing is essential for the brain to process visual stimuli from the left and right visual fields accurately. The other options refer to separate components of the visual system. The optic bulb pertains to structures involved in visual processing but does not specifically describe the crossing of nerve fibers. The optic disc is the point on the retina where the optic nerve exits the eye, which does not involve crossing fibers. The optic tract consists of the pathways that carry visual information from the optic chiasm to the visual cortex but does not represent the crossing point itself. Thus, the correct answer is indeed the optic chiasm, as it plays a pivotal role in how visual information is organized and interpreted by the brain.