Plastic vs. Polycarbonate Lenses- Which Are Better?

Plastic versus polycarbonate lenses

Same Prescription, Different Materials

When you go to the eye doctor and get your brand new prescription, the fun task of selecting  your new eyewear begins. But picking out your frame is only part of the work involved in getting  your new eyewear ordered. The more difficult, yet more important, decisions involve your lenses.

The frame you select is mainly cosmetic, but the lenses and options you choose to go in those frames can affect the way that you see the world.

You will be offered a vast array of lenses and options to select from, and, depending of your prescription, you will most likely be given, at a minimum, the choice between plastic (CR-39) or polycarbonate (aka, “poly”) lenses. Which ones should you choose?

This decision is part cosmetic, part optical/visual, part price, and part durability. Let’s address these issues one at a time:

  • Cosmetic- Unless your prescription is fairly minimal (the sphere “sph,” or first number on your prescription, is less than a -2.00), you will notice that polycarbonate lenses are thinner than plastic lenses. In a thick, plastic frame, this difference may not be noticeable, but in a thin wire, rimless, or semi-rimless style, the difference will be more obvious. Generally, we recommend you start considering a thinner lens option at a prescription of around -2.50 or above. Lenses for patients with a (+) prescription will find that their lenses are thicker in the center and thinner around the edges (unlike patients with a (-) prescription, whose lenses are thin in the middle and thicker around the edges), and so the “polycarbonate = thinner” concept does not apply to them.
  • Optical/Visual- Because polycarbonate is a denser type of plastic material than “standard”/CR-39 plastic lenses, it can actually slow down light passing through the lens more than the standard plastic lens, causing what is known as “chromatic aberrations” around the edges of the lenses. Chromatic aberration is when a lens begins split light into its component colors like a prism. So some wearers of polycarbonate lenses notice a color “halo” around light colored objects, the horizon, etc. This is quite uncommon, and even someone who notices it initially can usually adjust to the lenses simply by wearing them for a week or two straight.Plastic lenses, because they are thicker, tend to be heavier than a polycarbonate lens in the same exact prescription, so someone with a higher prescription should seriously consider this lens type for the sake of their nose!Polycarbonate lenses, even clear ones, are 100% UV protectant.
  • Price- Because polycarbonate is considered an “upgraded” lens option, it usually costs a bit more than plastic. Many insurances will either cover this upgrade, or give a discount on it, especially for individuals under the age of 18.
  • Durability- Because, as we mentioned earlier, polycarbonate is more dense than plastic, it tends to be much more scratch resistant. All polycarbonate lenses are hard coated as part of the finishing process of manufacturing the lens. It also tends to crack less than plastic lenses, so people getting semi-rimless (no frame on the bottom part of the lens) or rimless/drill mount glasses should consider polycarbonate at a minimum (although high-index lenses and trivex lenses are actually better for the drill mount frame styles).

We recommend that children and people who have active/hazardous jobs or hobbies should be in polycarbonate or trivex lenses exclusively. The reason for this is that, given the right conditions, a plastic lens could shatter into a patient’s eyes, while a polycarbonate or trivex lens is shatter-resistant, and is therefore safer.

We hope that this helps make your lens selection process a bit easier! Stay tuned for upcoming editions of “Eyeglass Lens Options” where we will discuss topics including Anti-Reflective (AR) Coatings, Trivex Lenses, the Pros and Cons of Transitions Lenses, and more!

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8 thoughts on “Plastic vs. Polycarbonate Lenses- Which Are Better?

  1. PALLAV KUMAR NAYAK says:

    MY POWERS ARE :

    RIGHT EYE :
    ““““““““`
    SPHERE : -3.0, CYLINDER : -1.0, AXIS : 75*, VISION : 6/6

    LEFT EYE :
    ““““““““
    SPHERE : -11.0, CYLINDER : NO, AXIS : NO, VISION : 6/9

    WHICH LENSES ARE THINNER FOR ME ??

    1.59 POLY-CARBONATE LENSES
    OR
    1.67 PLASTIC LENSES

    PLEASE HELP………..

    • There are a few factors here to consider. The absolute thinness of the lens is obviously one factor, but the clarity of your vision is also important. Sometimes polycarbonate can be thinner than high index lenses because you can ask for a 1.0mm center thickness in a polycarbonate, whereas you have to have a 1.5mm center thickness in other materials.

      The thing that I am most concerned about in your prescription is the discrepancy between your two eyes. Many times people that have prescriptions that are so far apart, power-wise, between the two eyes have a hard time “converging images.” Imagine, if you will, a magnifying glass. The closer you hold the magnifying glass to the thing you are looking at, the closer to “normal” size it appears to be. The farther away you hold the magnifying glass, the larger the object appears. The opposite of this effect occurs in a (-) lens like yours. The increase in power will behave like moving the lens farther away from the object. So, in your left eye, the object will appear much smaller than the object appears to your right eye, because the left eye has a much greater prescription. The brain wants your two eyes to see the same object at the same time (called “fusion”). It has a hard time merging images of very different sizes, such as the images you are getting from your right eye and your left eye. Sometimes glasses aren’t the answer in this case- contacts generally are easier to use when there is a huge discrepancy in prescriptions.

      If you were going to try to get glasses with this prescription, however, I would steer you towards the 1.60 or 1.67 lens materials. This is due mostly to the optics of the lens materials themselves. Polycarbonate is a very dense material that tends to give you a lot of peripheral distortions (basically, blurriness out of the sides of the lenses), especially in higher prescriptions.

      The only reason I may recommend polycarbonate would be for safety reasons- polycarbonate is a shatterproof lens, so if something were to accidentally hit you in the face, the polycarbonate wouldn’t shatter into your eyes like other lens materials might. 1.60 and 1.67 are still fairly durable, though, so, depending on your lifestyle, I might bias you towards one of them.

      Two more important things to add: 1.- try to purchase an asperhic lens (many of the higher index lenses will include this automatically, but check, just in case), and 2.- get an anti-reflective (also called anti-glare or AR) coating, especially if you choose the 1.60 or 1.67 materials.

      Hope this helped! Let me know if you have any further questions.

      • PALLAV KUMAR NAYAK says:

        Many Many Thanks Sir.

        I am so obliged that you have responded, honestly I haven’t expected a response from a busy professional like you.

        And you have explained my exact problem, even better than I used to explain my family.
        (Ya professionalism of-cores, not judging you sir, just can’t explain how excited I am).

        Thanks again. Here I want to take some more valuable times of yours. Please forgive my audacity.

        Sir, I am currently using 1.5 CR-39 Anti-scratch + Anti-glare lenses with a Half-Rim frame. With glasses I still found distance images blurred. I find it hard to judge the edges. I can’t detect exact shape, size, & speed of an object. At night it is worst.

        But without my glasses I am almost blind. I even can’t judge any face. So I am using eyeglasses 24*7

        I was told by many local optician that I can’t use contacts 24*7 So I am considering both Glasses and Contacts.

        Contacts : 10 am to 5 pm, Only During office hours
        Glasses : All day remaining, Full-on during Off-days

        For my new eyeglasses I am considering Anti-scratch + Anti-glare + Grey Transition Lenses.
        Now I have two options as material.

        a) 1.59 Poly-carbonate
        b) 1.67 Plastic

        Being an Electrical Engineer, I am less concern for safety from impact. Rather my main concern is Thickness (Looks, the more thinner is more suitable for my new frame) and Visual quality.

        Also if Transition is suitable for me.

        Please suggest me the best option for my powers.

        ——————————————————————————————————————————————————————————————————————

        RIGHT EYE :
        “““““““““`
        SPHERE : -3.0, CYLINDER : -1.0, AXIS : 75*, VISION : 6/6

        LEFT EYE :
        “““““““““`
        SPHERE : -11.0, CYLINDER : NO, AXIS : NO, VISION : 6/9

        WHICH LENSES ARE THINNER FOR ME ??

        1.59 POLY-CARBONATE LENSES

        OR

        1.67 PLASTIC LENSES

  2. I would definitely steer you towards the 1.67, then, if safety wasn’t a concern. The Transitions would be a personal preference- it shouldn’t have any bearing on the visual quality of the lenses (although you might notice a slight tint at all times, depending on what kind of Transitions you get. Again, this slight tint won’t affect the prescription in the lenses themselves, and most people wouldn’t even notice it).

    As far as the glasses not helping you see perfectly, I am not really surprised by this, as I explained in my earlier response. I think the contacts are definitely worth a try.

    Generally, I agree with the no-contacts-24/7 rule, as it is healthier for your eyes, although I defer to your optometrist in those matters, since you are not a patient here.

    Good luck! :-)

    • PALLAV KUMAR NAYAK says:

      Thanks Sir

      I checked lenses at a reputed store and found, for high powers like mine, there was no difference in thickness of 1.5 CR-39 lenses and 1.67 CR-39 Lenses. Or at-least no visual difference.

      After getting your valuable suggestions I took an appointment for CONTACTS in next week and for now ordered 1.5 CR ASPHERIC KODAK TRANSITION LENSES with RLX Plus (anti-scratch) and Clear (anti-reflective) coatings.

      Thanks again sir and my best wishes…………..

  3. Eugene says:

    My prescription is -1.0/-1.0 – would you recommend CR-39 or Poly?
    Also is surface anti reflective coating or inserted AR coating the way to go?

    Thanks!

    • Unless you were doing an activity that could be potentially dangerous to your eyes (for which you would want an impact resistant lens) and/or unless you were selecting a rimless or semi-rimless frame, I would go with a basic plastic lens in your prescription. You will not appreciate any tiny amount of thinness the polycarbonate may give you, and the lenses will have better optics.

      I have not heard or an inserted AR coating, so I’m not sure what you mean by this. Anti-reflective coatings in general are a great option to put on just about any pair of glasses.

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