Final answer:
The passage indicates that carrots bolster eye health through carotene, which is converted to vitamin A, vital for general vision health and preventing deficiencies that affect night vision.
Step-by-step explanation:
The main idea of the passage is that carrots enhance general eye health but do not specifically improve night vision. Carrots contain carotene, which is a pigment necessary for the body to produce vitamin A. This vitamin is essential for healthy skin, bones, teeth, and good vision. While vitamin A deficiency can lead to impaired night vision, there is no mention in the passage of recent studies showing that carrots directly improve night vision. Therefore, the idea that British pilots during World War II had superior night vision due to carrot consumption, or that carrots have no effect on eye health or vision, is not supported by the information given. Additionally, while vitamin A is indeed linked to eye health, it's worth noting that vitamins A and C can help prevent cataracts, a major cause of blindness.