Reading a prescription from your eye doctor can be difficult, even in the best cases. But filling out online prescription forms correctly is critical.
Filling Out Online Prescription Forms Correctly
Many eye doctors have sloppy handwriting, and many also have the habit of simplifying what they write because they expect a trained optical professional to be reading it. If you are shopping for eyeglasses online, you’re probably not a trained optical professional, and if you’re shopping on our web site, you’re probably also concerned with making sure you’re getting safety glasses that are appropriate to your application, let alone worrying about how to write up a prescription.
If you are not sure of what all the stuff on your prescription means, or how to enter it into one of our forms online, here’s what you need to know:
- Your eyes are marked on the prescription as OD (which is your right eye) and OS (which is your left eye). If you are unsure which is which, know that the OD right eye always comes first.
- All prescriptions have three categories of correction for each eye. The first is Sphere (or SPH), the second is Cylinder (or CYL), and the third is Axis. Your prescription may have all or some of these on it.
- Sphere is the correction for nearsightedness or farsightedness. It is positive or negative, and it goes in increments of 0.25. So, your prescription may be +1.25, 0.75, -2.00, +3.50, etc. This is written for each eye.
- Cylinder and Axis work together, so you can’t have one without the other (though you can have both for one eye and neither for the other). Cylinder is written much the same as sphere; it is positive or negative, and it goes in increments of 0.25. Axis is the amount that the cylinder is turned. In other words, where sphere is the same no matter whether the lens is upside up or turned 90 degrees, cylinder is different as you turn it, so the direction it needs to be turned must be specified on the prescription, which is where the Axis comes in. Axis is a degree measurement between 0 and 180.
- The measurements for sphere and cylinder always have two numbers after the decimal place. Sometimes eye doctors get careless and don’t put in the decimal. If your prescription has no decimal, you can expect it’s got two numbers after it. In other words, a prescription written as -250 is -2.50. A prescription written as -25 is -0.25. A prescription written as +100 is +1.00, and so on.
- Sometimes your doctor will write “SPH” in the cylinder section. This means that there is no cylinder.
- If you are getting a bifocal, its strength will usually be written on the prescription below the Sphere, Cylinder, and Axis section. It is usually marked “ADD,” “BIFOCAL,” or “NEAR.” It also may not be marked at all. It is almost always the same strength for both eyes, so many doctors only write it once instead of twice (once for each eye). It is always positive.
- Pupil distance is the distance between the centers of your pupils, measured in millimeters. It is often not written on the prescription and must be measured by you. If it is written there, it may be marked as PD.
- Segment height is the distance from the bottom of the lens to the top of your bifocal (which is the line on a lined bifocal, or the start of the progressive corridor on a progressive bifocal). For lined bifocals, it’s often estimated. For progressives, it is measured from the bottom of the lens to the center of your pupil (in millimeters) and is different for every frame.
If you have more questions about entering your prescription into one of our forms, give us a call so we can help you make the right decision about your glasses. Generally speaking, prescription safety glasses are a complicated business, so we have trained professionals ready to help you get your order in and feel secure that you made the right choice.
Shopping for safety glasses should be enjoyable and shouldn’t feel like a chore; you want to feel good about the glasses you’re going to have to work in, because it’ll help you stay motivated to keep them on when you’re supposed to.
We hope you have a further ideas on how to order prescription glasses online. Leave us a comment below and share them with us!