Question

Which is example of the Simple Myopic Astigmatism among the prescriptions given below:

• A. Rx (+) sphere
• B. Rx will be plano (-)
• C. Rx will be (-) sphere
• D. (-)(+) (+)(-) on both 90 and 180 degree axis

Answer 1

The Correct Option is B

Step 1: Decode each prescription by what the sphere and cylinder signs tell you about the two principal meridians.
Step 2: Simple myopic astigmatism means one meridian focuses on the retina (plano) while the other is short-sighted, so the sphere is plano and the cylinder is minus, i.e. plano with a $(-)$ cylinder.
Step 3: A plain $(+)$ sphere is simple hyperopia, a plain $(-)$ sphere is simple myopia, and a prescription with opposite-sign powers on the $90^\circ$ and $180^\circ$ meridians is mixed astigmatism.
Step 4: Matching the definition, the simple myopic astigmatism prescription is the plano $(-)$ one.
\[\boxed{\text{Rx will be plano (-)}}\]