A patient wearing a toric soft lens with parameters -1.50 -1.50 x180 has an over-refraction of -0.75 +0.50 x090. Which parameters should be ordered for a new lens?

To determine the correct parameters for a new toric lens after the over-refraction, it's essential to calculate the adjustments needed for both the sphere and cylinder components based on the over-refraction results.

The original lens parameters are -1.50 sphere, -1.50 cylinder, and axis 180. The over-refraction indicates that the patient requires an adjustment of -0.75 for the sphere and +0.50 for the cylinder at an axis of 090.

To find the new spherical power, subtract the over-refraction spherical component from the original spherical value: -1.50 (original) - 0.75 (over-refraction) = -2.25.

For the cylindrical power, we need to add the over-refraction cylindrical component to the original cylindrical value. Since the original cylinder is -1.50 and the over-refraction is +0.50, we convert +0.50 to -0.50 with the appropriate axis adjustment. The axis of the toric lens itself remains the same at 180 in this case, while the cylinder power is calculated: -1.50 (original) + 0.50 = -1.00, but since we are to adjust this correctly per the