What is the angle measuring standard for cylinder axis from .75 to 1.50D according to ANSI?

The standard for measuring the cylinder axis in the specified diopter range according to ANSI (American National Standards Institute) is set at 3 degrees. This means that when opticians are measuring the axis of cylindrical lenses, they are expected to make their measurements with an accuracy that allows for a maximum deviation of 3 degrees for prescriptions that fall between 0.75 and 1.50 diopters. This standard is crucial as it ensures consistency and precision in the fitting of lenses, which directly affects visual acuity for patients requiring cylindrical corrections. Maintaining strict adherence to this specification helps provide optimal visual outcomes and contributes to the overall quality of optical care.