According to Kestenbaum's rule, what ADD would you expect for a distance VA of 20/200?

• A. +5.00 Diopters
• B. +10.00 Diopters
• C. ++15.00 Diopters
• D. ++20.00 Diopters

Answer: (B)

Kestenbaum's rule uses the distance visual acuity converted to a decimal and then takes its reciprocal to estimate the near add. A Snellen of 20/200 converts to a decimal of 0.1; the reciprocal of 0.1 is 10. So the estimated near add is about +10 diopters. This rule provides a quick starting point for the near addition; in practice the exact add is refined based on the patient’s comfortable reading distance and other factors, but the test answer aligns with the +10 D estimate from the rule.