Full Explanations: Sphere, Cylinder and Axis in Glasses Prescription

Nowadays, more and more people start wearing glasses and some of them just take the prescription to the optical store to pick out a pair of glasses. When you hold the prescription, have you ever been curious to know what the number and letters mean for your eyesight? Do you know the meaning of the Sphere, Cylinder and Axis? If not, keep on your reading and you will find the full explanations in the following part.

Full Explanations: Sphere, Cylinder, and Axis in Glasses

In the eye prescription, there are some important elements you need to know including Sphere, Cylinder, and Axis. What does SPH mean for glasses? What is Cylinder in glasses? What does Axis mean for glasses? This post will explain them one by one.

What Does Sphere Mean for Glasses?

Sphere, often written as SPH, means that the correction for nearsightedness or farsightedness is spherical, equal in all meridians of the eye. It is measured with the unit diopters(D), indicating the lens power of the glasses. The Sphere is also used to correct the nearsightedness or farsightedness.

If you are nearsighted, you will see there is a minus sign(-) next to the Sphere number. If you are farsighted, you will see a plus sign(+) next to the Sphere number. What does SPH mean for glasses? After reading this part, you may get the answer.

What Is Cylinder in Glasses?

In the second part, we will explain what the Cylinder in glasses is. Cylinder means the amount of lens power for astigmatism and shows the differences between the greatest and weakest powers of the eye. It is usually separated by 90 degrees. If nothing appears in the Cylinder column, it indicates that you have no astigmatism, or your astigmatism is so light that there is no need to correct it with the eyeglass lenses.

The minus sign and the plus sign next to the Cylinder numbers are also for nearsightedness and farsightedness. Cylinder power always follows Sphere power in an eyeglass prescription.

What Is Axis in Glasses?

In the third part, we will show you what the Axis in glasses is. The Axis means the angle between the two meridians of an astigmatic eye. The Axis in your prescription is usually measured from 1 to 180. The number 90 means the vertical meridian of the eye and the number 180 means the horizontal meridian.

What’s more, if an eyeglass prescription includes cylinder power, it also must include an Axis value, which follows the CYL power. In the following picture, you can see an eye prescription.

In addition, you will see the initials OD and OS written on your eye prescription. These are the abbreviations that denote to Oculus Dexter and oculus sinister in Latin and mean left eye and right eye. That is to say, the OD means the right eye and OS means the left eye.

What does SPH mean for glasses? What is CYL in glasses? What does Axis mean for glasses? After reading this post, you may have gotten the answers. If you need a pair of glasses, the Koalaeye Optical may be a good choice for you. If you don’t know whether you need a pair of glasses, the post ‘How to Know If You Need Glasses? 10 Signs You Need Glasses’ may be helpful.

If you have any different ideas of the Sphere, Cylinder and Axis in glasses, you can leave a comment in the comment zone. If you have any problem with the glasses or the sunglasses, you can contact us via the email service@koalaeye.com.