Understanding Your Contact Lens Power Prescription When it comes to contact lenses, one of the most crucial factors in ensuring a comfortable and effective fit is understanding your prescription. This includes lenses designed for specific conditions, such as toric lenses for astigmatism. Unlike eyeglasses, which only require a simple SPH (sphere) measurement, a prescription for contact lenses includes additional parameters like BC (base curve), DIA (diameter), CYL (cylinder), and AXIS, each playing a significant role in your eye health and vision clarity. If you’ve ever been confused about these terms, don’t worry — this guide will walk you through everything you need to know about contact lens power and how to read your prescription. contact lenses What is a Contact Lens Prescription? A contact lens prescription is a detailed written…
What does axis in contact lenses mean?
The axis figure on prescription contact lenses is for people who have astigmatism and indicates the required location of cylindrical power on the lens. This determines the angle of vision correction that someone with astigmatism would need, due to the irregular curvature of their eye, which can be described as shaped like a rugby ball. Axis is part of your prescription, and tells an optometrist in which direction they must position any cylindrical power in your lenses that is required for astigmatism. The number shows the orientation or angle (in degrees) from 1 to 180. The number 90 means vertical position, and 180 horizontal. A higher number for the axis does not mean that your prescription is stronger, it simply describes the position of the astigmatism. Meridians of the eye are determined…