Which of the following visual effects can occur due to excessive positive G force?

The phenomenon of peripheral vision dimming, graying, or tunnel vision occurs due to excessive positive G force primarily because of the way G forces affect blood flow and pressure in the body. When a pilot experiences high positive G forces, blood is pulled away from the head and upper body towards the lower extremities due to the increased gravitational pull. This reduction in blood flow affects the optic nerve and the visual cortex, leading to a temporary loss or dimming of peripheral vision. As a result, the pilot may experience a narrowed field of vision, often described as tunnel vision.

This physiological effect can significantly impact a pilot’s situational awareness and ability to perceive important visual information outside their central line of sight, which is critical during flight operations. Understanding the implications of G force on vision helps pilots manage their performance effectively under high-stress conditions.

The other choices deal with vision or sensory enhancements that do not correspond to the effects of high positive G forces. Enhanced night vision, for instance, is not a result of G forces but rather relates to adaptation of the eyes to low light levels. Similarly, increased depth perception is generally not associated with the high G environments, as the distortion of visual input would likely hinder rather than enhance depth perception. Complete loss