If you would like to know how to read an eyeglass prescription, then you have come to the right place! Eyeglass prescriptions contain all sorts of abbreviations and numbers that can be very difficult to understand.
- Left and Right. The first step in understanding how to read an eyeglass prescription is understanding which eye the prescription is talking about. You will see two abbreviations on your eyeglass prescription, OD refers to the right eye, while OS refers to the left eye.
- Diopter. When you take a look at your eyeglass prescription, you will notice a bunch of numbers. The second step in understanding how to read an eyeglass prescription is understanding what those numbers mean. Those numbers are diopters, which is a unit used to measure the correction of the lens your eyes require. A plus sign in front of the diopter numbers means that you are farsighted, while a minus sign means that you are nearsighted.
- Sphere. Learning how to read an eyeglass prescription means that you have to understand what the sphere reading on your eyeglass prescription means. The sphere, or spherical, part of your eyeglass prescription will use the diopter numbers to note if you are farsighted, nearsighted, or if you have no refractive error. If you have no refractive error, instead of a number, you will see the word plano, or the abbreviation pl.
- Cylinder. The next step in understanding how to read an eyeglass prescription is knowing what the cylinder reading stands for. The cylinder reading is often abbreviated with the letter C, and the C refers to astigmatism. Like the sphere reading, the cylinder reading can have a positive or negative diopter number. The bigger the cylinder reading is, the more astigmatism you have.
- Axis. The final step in understanding how to read an eyeglass prescription is know what the axis reading stands for. The axis reading will be anywhere between 0 and 180 degrees. Basically, the axis number reveals the orientation of the astigmatism you have. The axis depicts the location of the irregularity within your eye. If you have no astigmatism, the cylinder and axis columns may be blank.
As always, if you have any specific questions regarding your eyeglass prescription, consult your optometrist.