Stereopsis test is a type of eye examination used to evaluate binocular vision and depth perception. It is a measurement of the brain's ability to process two slightly different images from each eye into a single, 3-dimensional image.

There are several symptoms that may indicate a need for a stereopsis test, including:

1. Difficulty with depth perception or judging distances.
2. Double vision or ghosting images.
3. Blurred or fluctuating vision.
4. Eye strain or headaches, especially after prolonged visual tasks.
5. Eyestrain or fatigue, especially after prolonged visual tasks.
6. Dizziness or balance problems.
7. Squinting or tilting the head to maintain single vision.
8. Closing one eye to maintain single vision.
9. Reduced visual acuity in one eye compared to the other.

Early detection of binocular vision issues, such as strabismus (eye misalignment), amblyopia (lazy eye), and stereoblindness (inability to perceive depth), is important to reduce the risk of permanent vision loss.