Lenses and PD Guides

Pupillary distance (PD) is the distance between the pupils of your two eyes. It is an essential measurement when buying a new pair of eyeglasses or presciption sunglasses. For greatest comfort and clarity, the optical center of each lens of your glasses should be aligned directly in front of the center of your pupil. 

PD is measured in millimeters (mm). The average pupillary distance for an adult is about 63 mm, but this is not a number you’ll want to assume. Pupillary distance can vary widely — roughly between 51 mm and 74.5 mm for women and 53 mm and 77 mm for men.

Pupillary distance measurements usually are taken when you are being fitted for glasses after your eye exam. An optician typically will measure your PDs with a high-precision measuring device called a pupillometer.

But let's say you have your eyeglass prescription and want to buy a stylish pair of eyeglasses online. You need your PD measurement for that. 

Don't worry. You can measure your own PD in a pinch. All you need is a milimeter ruler and a mirror. If you have a ruler that is in inches you can send us that mesuresement and we will convert it for you into mm. 

There are two types of pupillary distance measurements:

• Monocular PD. This is the distance between the center of your pupil and the middle of the bridge of your nose. Monocular PDs are required for accurate fitting of progressive lenses.

• Binocular PD. This is the distance between the center of the pupil of one eye and the center of the pupil of the other eye.

Due to facial asymmetry, monocular PDs aren't always exactly the same. But the sum of your two monocular PD measurements should always equal your binocular pupillary distance.

If you already wear prescription eyeglasses, here's an alternate way to measure your pupillary distance. You just need a non-permanent marker for this one.

1. Wearing your glasses, stand in front of a mirror (about 12 inches away).

2.  Close your right eye.

3. Using just your left eye, put a small mark on the left lens of your glasses, directly in front of your pupil.

4. Without moving your head, close your left eye and open your right eye.

5. Using just your right eye, put a small mark on the right lens of your glasses, directly in front of that pupil.

Take off your glasses and measure the distance between the two dots on your glasses. This is your distance binocular PD. 

Note: Do-it-yourself PD measurements frequently are not as accurate as the pupillary distance measurements taken by a skilled optician. For best results, have an eye care professional measure your pupillary distance (PD) before buying new glasses.

Digital Lenses are optical lenses that have been digitally altered to provide a significant improvement in clarity over standard lenses. When the digital lens is combined with an anti reflective coating the clarity improves.

Transition lenses contain special patented photochromic dyes that cause the lens to activate, or darken, when exposed to ultraviolet rays from sunlight. When the UV light diminishes, the lenses fade back. As light conditions change, the level of tint adjusts, offering the right tint at the right time. It's important to note that the UV radiation blockage remains constant. Transitions lenses provide automatic protection from UV radiation in both the clear and darkened states and represent a truly superior technology.

Polarized sunglasses are designed to reduce glare from surfaces such as water, snow, and glass. Glare distorts the true color of objects and makes them harder to see.

Glare isn't just annoying. It can be dangerous, especially when you're driving. Sun glare has been linked to pedestrian deaths and other traffic accidents.

Polarized sunglasses can help drivers and athletes see more clearly and avoid hazards.

This article explains how polarized lenses work. It also outlines some of the benefits and drawbacks of this kind of eyewear.

Anti-reflective coating (also called "AR coating" or "anti glare coating") improves vision, reduces eye strain and makes you eyeglasses look more attractive. These benefits are due to the ability of AR coating to virtually eliminate reflections from the front and back surfaces of your eyeglass lenses.

With reflections gone, more light passes through your lenses to optimize visual acuity with fewer distractions (especially at night), and the lenses look nearly invisible — which enhances your appearance by drawing more attention to your eyes and helping you make better eye contact with others.