Final answer:
Tunnel vision is a condition characterized by peripheral vision loss, where the patient can only see straight ahead. This is different from myopia, presbyopia, and astigmatism, which affect how clearly a person can see at different distances.
Step-by-step explanation:
The condition where a patient can see only straight ahead and has peripheral vision loss is known as tunnel vision. In choices A and B, myopia refers to nearsightedness, which is the inability to see distant objects clearly, and presbyopia is an age-related condition that affects the ability to see close objects clearly. Choice D, astigmatism, is a condition that leads to blurred vision due to the irregular shape of the cornea or lens. Therefore, the correct answer is C) Tunnel vision.