Buying prescription glasses online for the first time can feel intimidating. How do you know you’re doing it right?

Prescription Safety Glasses: An Online Shopper’s How-To

Prescription safety glasses aren’t much different from regular glasses when you’re ordering them online, but if you’ve never entered your prescription into an online form before, it can seem a little daunting.

When ordering your prescription safety glasses, it’s important to pay special attention to the numbers on your prescription. Making a mistake such as switching a plus and a minus can make your glasses unusable, so double check all of your entries before you submit your order. Also, if you’re getting ready to order, make sure you take a look at our post about coatings so you know which one is right for you.

Here’s a good list of tips to go by when purchasing prescription safety glasses online:

• Your eyes are marked on the prescription as OD (right eye) and OS (left eye).
• On every part of your prescription, the right eye is always listed before the left eye.
• When entering your prescription, make sure you use the right sign for Sphere and Cylinder. These numbers will always be either positive (marked with a “+”) or negative (marked with a “-“). Switching a -2.00 to a +2.00 will make your glasses unusable.
• The Sphere and Cylinder markings on your prescription will always have two numbers after the decimal point. This means that, if your doctor wrote “-225” you can expect that the prescription is “-2.25” because there are two numbers after the decimal place. This is even true if the doctor writes a smaller number like “+50”; that means the prescription is “+0.50”.
• The Cylinder and Axis work together on a prescription. If one of your eyes has cylinder with no axis or axis with no cylinder, call your doctor.
• Sometimes the doctor will write “SPH” in the cylinder column. This means there is no cylinder in that eye.

• Pupil Distance, or PD, is the distance between your pupils, measured in millimeters. This is an important measurement but is not always on the prescription. If you don’t have your PD, you may be able to get it from your eye doctor, or you can watch our video on How to Measure PD to learn how to measure it yourself.
• If Pupil Distance is marked on your prescription, it may be marked as one number or as two numbers, one for the right eye and one for the left eye. There may also be a PD for near vision. Since your pupils converge slightly when you are looking at something close, your PD is slightly narrower when you’re reading or doing up-close work. We account for this, so you do not need to enter your “Near PD” into our form.
• Segment height is the distance from the bottom of the lens to the top of a bifocal, measured in millimeters. For a lined bifocal, this is often set to a standard, so you can leave segment height blank. For progressive bifocals, it’s measured from the bottom of the lens to the center of your pupil. Segment height is different for every frame you use, and it is not needed for Single Vision prescriptions.
• If you are getting a bifocal, the strength of the bifocal will be marked as “Bifocal,” “ADD,” or “Addition.” It is always positive and almost always the same strength for both eyes.

Once you’re familiar with how the numbers are laid out on your prescription it becomes much easier to fill out a prescription order form online. If this is your first time ordering prescription glasses online and you’re not sure about something, you should definitely contact us to ask a question so you know you are doing things correctly.

Hopefully this post makes you a little more confident about ordering prescription safety glasses online! Shopping for prescription safety glasses should be an enjoyable experience, so being comfortable with filling out your order form is important.

If you have any comments or questions, give us a call or leave a comment on this post. Thanks so much for reading, and stay safe!