Using Kestenbaum's rule, which ADD is recommended for a distance VA of 20/200 when the goal is 20/20?

Using Kestenbaum's rule, which ADD is recommended for a distance VA of 20/200 when the goal is 20/20?

• A. +5.00 Diopters
• B. +8.00 Diopters
• C. +10.00 Diopters
• D. +12.00 Diopters

Answer: (C)

Kestenbaum's rule gives a quick way to estimate the near add needed to bring a very reduced distance vision up to 20/20 by using the reciprocal of the near focus distance (in meters) you’d aim for. In practical terms, if the goal is to read at 20/20, the rule uses the distance at which that line would be seen with the added power and translates that distance into diopters. For a distance vision of 20/200, aiming to achieve 20/20 translates to focusing at about 0.1 meters (10 cm). The reciprocal of 0.1 m is 10, so the recommended near add is roughly +10 diopters. This large add corresponds to a near-working distance of around 10 cm, which is the strength needed to pull the image toward the retina and allow clear near reading to match 20/20 distance vision under this rule. In practice, this is a rule-of-thumb, and actual prescriptions may vary based on the patient’s accommodation, ocular health, and intended tasks. But for this scenario, +10 diopters is the best estimate using Kestenbaum's approach.

Kestenbaum's rule gives a quick way to estimate the near add needed to bring a very reduced distance vision up to 20/20 by using the reciprocal of the near focus distance (in meters) you’d aim for. In practical terms, if the goal is to read at 20/20, the rule uses the distance at which that line would be seen with the added power and translates that distance into diopters.

For a distance vision of 20/200, aiming to achieve 20/20 translates to focusing at about 0.1 meters (10 cm). The reciprocal of 0.1 m is 10, so the recommended near add is roughly +10 diopters. This large add corresponds to a near-working distance of around 10 cm, which is the strength needed to pull the image toward the retina and allow clear near reading to match 20/20 distance vision under this rule.

In practice, this is a rule-of-thumb, and actual prescriptions may vary based on the patient’s accommodation, ocular health, and intended tasks. But for this scenario, +10 diopters is the best estimate using Kestenbaum's approach.