American Board of Opticianry (ABO) Practice Test

A patient with a prescription of -0.50 OU and +2.00 wants a reading-only pair, what would the new prescription be?

1. A. +1.50 OD

2. B. +1.50 OS

3. C. +1.50 OU

4. D. -1.50 OD

The correct answer is: C. +1.50 OU

When a prescription is given in a negative value for both eyes (OU), it means that the patient has nearsightedness in both eyes. However, when adding a reading prescription, it is important to take into consideration the patient's dominant eye and non-dominant eye. In this case, the patient's dominant eye has a prescription of +2.00, which means the non-dominant eye should have a prescription that is slightly less, to provide proper balance and focus while reading. Therefore, the new prescription for reading-only would be +1.50 in both eyes (OU). The other options listed (-0.50 OD, +1.50 OS, and -1.50 OD) do not take into consideration the patient's dominant eye and would not provide the proper correction for reading-only.