ABO NOCE Practice Test 2026 - Free Optician Certification Practice Questions and Study Guide

When objects are viewed through a Base In or Base Out prism, they exhibit a specific visual effect where they seem tilted or appear higher or lower than their actual position. This is due to the way prisms refract light. When light passes through a prism, it bends and alters the perceived location of objects.

In the case of a Base In prism, light is directed toward the nose, which can create the visual perception that objects are displaced to the side, giving them a tilted appearance. Conversely, with a Base Out prism, light diverges away from the nose, which can also lead to a similar effect but in the opposite direction. Consequently, this tilting effect affects depth perception, making objects seem higher or lower in vertical alignment.

This phenomenon highlights how prisms manipulate visual input, altering our perception of object positioning through changes in light direction and ultimately affecting how we interpret spatial relationships in our environment. Understanding this effect is essential for applications in vision therapy and managing conditions like binocular vision disorders.