To improve night vision, a target should be focused approximately how many degrees off the fovea?

To improve night vision, a target should be focused approximately how many degrees off the fovea?

• A. 5 to 10 degrees
• B. 10 to 15 degrees
• C. 15 to 20 degrees
• D. 20 to 25 degrees

Answer: (B)

Focusing a target approximately 10 to 15 degrees off the fovea is essential for improving night vision due to the distribution of photoreceptors in the retina. The fovea contains a high density of cones, which are responsible for color vision and function best in well-lit conditions. However, in dim lighting, the rods, which are more abundant in the peripheral areas of the retina, are more effective for detecting light and movement. When a target is positioned 10 to 15 degrees off the fovea, it aligns more closely with the areas rich in rods. This placement takes advantage of the rods’ greater sensitivity to low light conditions, enhancing the ability to see objects that may not be clear when looked at directly with the fovea. As a result, this method allows for better visual perception in low-light environments, making 10 to 15 degrees the optimal range for focusing to enhance night vision.

Focusing a target approximately 10 to 15 degrees off the fovea is essential for improving night vision due to the distribution of photoreceptors in the retina. The fovea contains a high density of cones, which are responsible for color vision and function best in well-lit conditions. However, in dim lighting, the rods, which are more abundant in the peripheral areas of the retina, are more effective for detecting light and movement.

When a target is positioned 10 to 15 degrees off the fovea, it aligns more closely with the areas rich in rods. This placement takes advantage of the rods’ greater sensitivity to low light conditions, enhancing the ability to see objects that may not be clear when looked at directly with the fovea. As a result, this method allows for better visual perception in low-light environments, making 10 to 15 degrees the optimal range for focusing to enhance night vision.