National Vision Optometric Technician Level 2 Practice Test

In a contact lens prescription, "B.C." stands for the base curve of the lens. This measurement is critical as it refers to the curvature of the back surface of the lens. The base curve is designed to fit the natural curvature of the cornea and can significantly affect how well the lens fits and functions on the eye.

A properly matched base curve is essential for visual acuity, comfort, and overall eye health. If the base curve is too flat or too steep compared to the patient's cornea, it can lead to discomfort, irritation, and potentially poor vision. Therefore, it is important for optometric technicians to understand that "B.C." is directly related to the fit and effectiveness of contact lenses, rather than indicating other options such as brand name or visual acuity.