A patient's prescription is -2.50 +1.00 x 175. What is the minus cylinder transposition?

To transpose the prescription -2.50 +1.00 x 175 into the minus cylinder format, we need to follow a specific formula used in optics for converting between plus and minus cylinder prescriptions.

First, in the given prescription, the spherical component is -2.50, and the cylindrical component is +1.00 at an axis of 175 degrees. In transposition, the spherical and cylindrical components are adjusted, and the axis is changed.

The process involves the following steps:

1. Add the cylindrical value to the spherical value:

• Here, you take the -2.50 and add the cylindrical value (+1.00).

• This results in: -2.50 + 1.00 = -1.50.

2. Change the sign of the cylindrical component:

• The cylindrical value changes from +1.00 to -1.00.

3. Adjust the axis:

• The axis of the cylindrical component also changes. The new axis is found by adding 90 degrees to the original axis of 175 degrees.

• 175 + 90 = 265 degrees. Since the axis is typically expressed between 0 and