Which formula expresses Hofstetter's average amplitude of accommodation?

Which formula expresses Hofstetter's average amplitude of accommodation?

• A. 18.5 - 1/3(age)
• B. 25 - 0.4(age)
• C. 15 - 1/4(age)
• D. 20 - age

Answer: (A)

Hofstetter’s average amplitude of accommodation decreases predictably with age and is commonly represented by the rule AA ≈ 18.5 − 0.3 × age. The option that uses 18.5 minus about one third of age matches this standard form closely (0.333 approximates 0.3), so it best reflects the typical average decline. For context, this formula yields values that are reasonable across ages: high teens to around a few diopters as age increases. The other formulas would imply too steep or too shallow a decline, or even negative values at practical ages, making them less consistent with the usual average accommodation. So, this option is the best representation of Hofstetter’s average amplitude of accommodation.

Hofstetter’s average amplitude of accommodation decreases predictably with age and is commonly represented by the rule AA ≈ 18.5 − 0.3 × age. The option that uses 18.5 minus about one third of age matches this standard form closely (0.333 approximates 0.3), so it best reflects the typical average decline.

For context, this formula yields values that are reasonable across ages: high teens to around a few diopters as age increases. The other formulas would imply too steep or too shallow a decline, or even negative values at practical ages, making them less consistent with the usual average accommodation.

So, this option is the best representation of Hofstetter’s average amplitude of accommodation.