The formula to calculate the power of a crossed cylinder lens (P) is:
\[ P = F1 + F2 + (F1 \times F2 \times d) \]
Where:
A crossed cylinder is a type of lens used in optometry that has curvature in two orientations that are perpendicular to each other. One surface of the lens is shaped like a convex or concave cylinder, while the other is shaped like a cylinder that is rotated 90 degrees from the first. This allows the lens to correct for both astigmatism and other refractive errors like myopia or hyperopia at the same time.
Consider an example where:
Using the formula to calculate the power of the crossed cylinder lens:
\[ P = 2 + 3 + (2 \times 3 \times 0.1) = 5.6 \text{ Diopters} \]
This means that the power of the crossed cylinder lens for this example is 5.6 Diopters.
