Which is the minimum Hofstetter formula for near accommodative amplitude in terms of age?

• A. 15 - 0.25 x age
• B. 18 - 0.33 x age
• C. 12 - 0.5 x age
• D. 20 - 0.3 x age

Answer: (A)

Accommodative ability declines with age, and Hofstetter’s formulas give practical estimates for near focus capacity at any age. For the minimum near accommodative amplitude, the established formula is AA_min = 15 − 0.25 × age (in diopters). This sets the lower bound you’d expect for a healthy eye performing near tasks; values below can indicate accommodative insufficiency, while values above are more than sufficient for typical near work.

For example, at age 25 the minimum predicted amplitude is 15 − 0.25×25 = 8.75 D; at age 40 it becomes 15 − 0.25×40 = 5 D. The other common Hofstetter estimates use different intercepts or slopes (mean or maximum), but the question asks for the minimum, which matches the 15 − 0.25 × age formula.