When the given prescription is transposed, what does it read?

To understand the concept of transposing a prescription, it's essential to know how cylinder prescriptions work. The process involves converting a prescription from one format to another, specifically adjusting the sphere, cylinder, and axis values while maintaining the same optical effect.

In transposing a prescription, the sphere and cylinder values are modified, and the axis is recalculated. If the original prescription has a negative cylinder, for example, after transposing, that cylinder becomes a positive value and must be added to the sphere value. The axis is also adjusted accordingly, and it often shifts by 90 degrees because of the change in the cylindrical value.

For the correct answer, the transposition results in a prescription indicating a right eye (OD) with a sphere of -0.50, a cylinder of -1.50, and an axis of 165 degrees. This suggests that the original prescription had a positive cylinder that converted to a negative sphere after calculation, reflecting the adjustment characteristic of the transposition process.

This is a crucial skill in optometry, as accurate transposition is necessary for ensuring correct lens prescription and ultimately, proper visual correction for the patient.