Question

Monovision problem solving example:

Spec Rx (OD -3.25 -0.50 x 180, OS -4.00DS, Add +2.00)
Patient CL Rx in Air Optix Aqua 8.6/14.2
OD -3.50 DS
OS -2.00 DS

What Rx would you prescribe over CLs for near tasks?

a) OD: -3.25 -0.50 x 180, OS: -2.00 DS, Add +2.00
b) OD: -3.50, OS: -4.00, Add +2.00
c) OD: -3.25 -0.50 x 180, OS: -4.00DS, Add +2.00
d) OD: -3.50, OS: -2.00, Add +2.00

Answer 1

The correct prescription over contact lenses for near tasks would be OD: -3.50 DS and OS: Plano (0.00), given that the OS eye is set for near tasks and the add power of +2.00 cancels out the myopia correction in the contact lens prescription for that eye.

Step-by-step explanation:

When approaching a monovision prescription over contact lenses for near tasks, we need to consider the patient's current contact lens prescription and the additional requirement for near vision (add power).

The patient's current contact lens prescription is OD -3.50 DS (spherical) and OS -2.00 DS. Assuming monovision, where one eye (typically the dominant eye) is corrected for distance and the other for near, we only need to add the reading addition to the near-vision eye. Given that the add power is +2.00, this should be applied to the eye set for near tasks. In this case, assuming the OS is for near, we add +2.00 to the current OS prescription.

The OD is kept the same as the contact lens prescription because it's for distance. Thus, the prescription for over the contact lenses for near tasks would be:

• OD: -3.50 DS (same as contact lens prescription)
• OS: Plano (0.00), as the -2.00 DS of the contact lens plus the +2.00 add makes it zero.

No additional cylindrical correction is needed over the contact lenses, as the question pertains to near correction only.