Which of the following is a sign of oxygen toxicity?

Tunnel vision is a recognized sign of oxygen toxicity, particularly in the context of high-pressure oxygen environments. When a diver is exposed to elevated levels of oxygen for extended periods, especially beyond partial pressures of 1.4 ATA (atmospheres absolute), the central nervous system can become adversely affected. This response can trigger various neurological symptoms, one of which is tunnel vision. This occurs due to changes in the retina and the brain's processing of visual information, leading to a narrowing of the visual field.

Understanding the physiological effects of oxygen at high pressures is crucial for divers. As they operate at deeper depths or during longer dives, awareness of such signs can help mitigate risks associated with oxygen toxicity, enhancing safety and reinforcing the importance of monitoring one's environment and body's reactions.