Chromatism is the name of the rainbow coloured fringes seen around high contrast borders. These become more noticeable when a person looks away from the centre of lens, especially in high powered lenses.
The website linked here has a worksheet you can use to calculate the distance from the lens centre where patients will notice chromatism in high powered lenses.
TIP: Print and photocopy these forms for making the Clinically Noticeable Chromatism in your eye-care practice.
Click here to go to the page: Then scroll to >Dispensing Aids.