Which test is specifically used to assess stereopsis?

The Wirt test is specifically designed to assess stereopsis, which is the ability to perceive depth and three-dimensional structure due to the slightly different images projected on each retina by the eyes. This ability relies on binocular vision and the brain's processing of these two separate images to create a cohesive perception of depth.

In the Wirt test, the individual views a set of circles (often with embedded designs) arranged in a specific way, and the examiner asks about the perceived distances or alignments of the patterns within the circles. This evaluation directly measures the function of stereo vision, as participants are required to utilize both eyes to judge depth and distance effectively.

The other tests listed assess different visual functions. The Snellen test evaluates visual acuity, measuring how well a person can see details at a specific distance. Color vision tests focus on an individual's ability to distinguish colors, which is unrelated to depth perception. Contrasting sensitivity assessments measure the ability to distinguish objects from the background in varying levels of contrast, not directly assessing how depth is perceived through binocular vision. Thus, the Wirt test is the most appropriate choice for evaluating stereopsis.