Final answer:
The normal vision screen for a 3-year-old checks for proper development and potential issues. Children at this age typically have a good range of vision, similar to adults, but are monitored for early signs of vision problems such as myopia.
Step-by-step explanation:
The normal vision screen for a 3-year-old child is designed to ensure that the child's eyes are developing as expected and to spot any potential issues with vision, such as myopia or difficulty in accommodation. While a newborn's vision is limited, only capable of focusing on objects directly in front and at a short distance, a 3-year-old's vision has developed significantly. At this age, a child should typically be able to see at a range similar to an adult. It is also the time when issues like nearsightedness can be identified and addressed.
The typical eye's power, measured in diopters (D), ranges from 50.0 D for distant vision to 54.0 D for close vision, with close vision demonstrating an 8% increase in power for accommodation. While this degree of accommodation is standard for a 40-year-old, children are expected to have a greater ability to accommodate. If there are vision issues identified, corrective measures such as glasses can be discussed with an optometrist.