This online tool converts an eyeglass prescription from plus-cylinder notation to minus-cylinder notation, or vice-versa. It performs the necessary mathematical transformations to ensure the lens power remains equivalent regardless of the notation used. For example, a prescription written as +1.00 +2.00 x 90 can be converted to an equivalent prescription using minus-cylinder notation.
The ability to readily convert between these notations is essential for optometrists, ophthalmologists, and opticians. It ensures clear communication and consistent lens fabrication, regardless of regional preferences or specific equipment requirements. Historically, different regions and manufacturers have favored one notation over the other, making this conversion capability crucial for interoperability. Accurate conversion prevents errors in lens manufacturing and ensures the patient receives the intended correction.