Pupil diameter light adaptation calculation

Steps:

• Identify pupil diameter in complete darkness: 8.0 mm.
• Identify pupil diameter at 1000 arbitrary light units: 3.65 mm (from graph or table).
• Compute absolute decrease: 8.0 mm - 3.65 mm = 4.35 mm.
• Calculate percentage decrease: (4.35 / 8.0) × 100 = 54.375%, rounded to 54.4%.

Why D is correct:

• 54.4% precisely matches the formula for percentage decrease using standard physiological data for pupil constriction in bright light.

Why the others are wrong:

• A: Results from using an incorrect final diameter of about 4.3 mm.
• B: Arises from approximating decrease as 4.27 mm without rounding properly.
• C: Comes from a calculation error, like dividing by 8.1 mm instead of 8.0 mm.

Final answer: D