An 18-year-old's vision is 20/30. What does this indicate?

The correct answer demonstrates an important understanding of how visual acuity is measured. When a person's vision is noted as 20/30, it indicates that they can see at 20 feet what a person with normal vision (which is considered 20/20) can see at 30 feet. This means that the individual has slightly less than perfect vision, as they need to be closer to the object to see it clearly compared to someone with standard visual acuity.

In clinical practice, the 20/30 measurement helps identify the need for further evaluation or potential corrective measures, but it does not automatically imply that the individual cannot engage in contact sports or requires a specialist's referral. Understanding this ratio is fundamental in assessing vision during any health examination focused on the eyes.