How is the optical zone calculated?

The optical zone is calculated by dividing the K reading by 337.5. This method provides a measurement relevant to the curvature of the cornea, which is essential in fitting contact lenses. The K reading, which reflects the steepest and flattest meridians of the cornea, needs to be adjusted based on this standard measurement to determine the appropriate optical zone for contact lens fitting.

This calculation is important because it helps ensure that the contact lens aligns correctly with the curvature of the eye, thereby enhancing comfort and visual acuity for the wearer. Properly determining the optical zone not only aids in fitting but also in assessing the overall fit of the lens and its suitability for the patient's eye shape and visual requirements.