What Does Sph Stand For In Eyeglasses
What Does Sph Stand For In Eyeglasses
Understanding the intricacies of eyeglasses requires familiarity with various components and their functions. Among these components, the mysterious acronym "SPH" often appears on prescriptions, leaving many wondering about its significance. This introductory paragraph aims to shed light on the meaning and importance of SPH in the realm of eyeglasses.
What Does Sph Stand For In Eyeglasses?
Have you ever wondered what the abbreviation "SPH" means on your eyeglasses prescription? It stands for "sphere," and it's a measurement of the amount of correction you need to correct nearsightedness or farsightedness. Nearsightedness, also known as myopia, is when you can see objects up close clearly, but things far away appear blurry. Farsightedness, also known as hyperopia, is the opposite - you can see things far away clearly, but objects up close appear blurry. Astigmatism is a condition in which the cornea or lens of the eye is not perfectly round, causing blurred vision at all distances.The SPH measurement is expressed in diopters (D). A diopter is a unit of measurement that describes the power of a lens. The higher the diopter number, the stronger the lens. For example, a -2.00 D lens is stronger than a -1.00 D lens. If your SPH measurement is positive, you are farsighted. If your SPH measurement is negative, you are nearsighted.
How Is SPH Measured?
Your eye doctor will measure your SPH using a device called a phoropter. A phoropter is a machine that has different lenses that can be flipped in front of your eyes. Your eye doctor will ask you to look at a chart with letters of different sizes and will flip different lenses in front of your eyes until you can see the letters clearly. The lens that gives you the clearest vision is the lens that has the correct SPH measurement.
What If I Have Astigmatism?
If you have astigmatism, your eye doctor will also measure your cylindrical power (CYL) and axis. The CYL measurement describes the amount of astigmatism you have, and the axis measurement describes the direction of the astigmatism. Your eye doctor will use these measurements to prescribe eyeglasses or contact lenses that will correct your astigmatism.
What If I Need Bifocals Or Trifocals?
If you are over the age of 40, you may start to develop presbyopia, which is a condition in which the lens of the eye becomes less flexible and makes it difficult to see objects up close. If you have presbyopia, your eye doctor may prescribe bifocals or trifocals. Bifocals have two different prescriptions, one for distance vision and one for near vision. Trifocals have three different prescriptions, one for distance vision, one for near vision, and one for intermediate vision.
If you have any questions about your eyeglasses prescription, be sure to ask your eye doctor. They will be able to explain what the different measurements mean and how they affect your vision.
