Certified Ophthalmic Assistant Practice Exam

In minus cylinder notation, the given prescription -2.50 +1.00 X175 can be converted to plus cylinder format by adding the sphere and cylinder powers algebraically and changing the axis by 90 degrees. Therefore, -2.50 +1.00 X175 is equivalent to -1.50 -1.00 X 85. This means that the correct answer is A.