Rimless and Semi-Rimless Lens Materials: Polycarbonate vs High-Index MR-8 Resin
If you're comparing polycarbonate and high-index MR-8 resin for rimless or semi-rimless glasses, the published evidence we can point to doesn't establish that one beats the other for drilled mounting points. Manufacturer information from PPG describes Trivex, a related high-tensile material, as well suited to rimless and semi-rimless frames, but that's a separate claim about a different material rather than a resolved MR-8-versus-polycarbonate comparison. The decision that actually matters is confirming your exact finished lens material and mounting compatibility with your eyewear provider before you place an order.
Key Takeaways
- No published, rimless-specific evidence shows MR-8 outperforming polycarbonate, or the reverse, for drilled mounting points.
- PPG's manufacturer information describes Trivex as well suited to rimless and semi-rimless frames, but this doesn't extend into a direct MR-8-versus-polycarbonate comparison.
- Claims that CR-39 or 1.67 resin chip more easily at drill holes than MR-8 or polycarbonate aren't backed by the evidence available to us.
- Before ordering, confirm the exact lens material, drilling or mounting compatibility, and any prescription or frame limits with your provider.
MR-8 vs polycarbonate: what the evidence can establish
The evidence available to us doesn't support picking MR-8 over polycarbonate, or polycarbonate over MR-8, for rimless glasses or semi-rimless mounting. Both are widely used in drill-mount and supra frames, but we don't have a direct, publishable comparison of how each holds up at a drilled edge specifically. Rather than guess, it's more useful to see where the evidence actually stops.
| Material | What the evidence establishes | Decision implication |
|---|---|---|
| Polycarbonate | No published rimless-specific comparison data found | Confirm mounting compatibility with your provider |
| High-index MR-8 resin (1.60) | No published rimless-specific comparison data found | Confirm mounting compatibility with your provider |
| CR-39 | No published evidence of a chipping difference at drill holes | Don't rule it out based on an unverified brittleness claim |
| 1.67 resin | No published evidence of a chipping difference at drill holes | Same caution applies |
| Trivex | In PPG manufacturer guidance, Trivex is described as especially well-suited to rimless and semi-rimless styles, while noting that impact-resistant lenses are never unbreakable and coatings can change impact resistance | Useful context for Trivex specifically, not a stand-in for the MR-8/polycarbonate comparison |
That table shows the honest state of things: we have a bounded, manufacturer-sourced statement about Trivex, and nothing comparable for MR-8 versus polycarbonate. Absence of a documented difference is not proof the two perform the same at a drilled edge. Readers who want more background on how resin index and chemistry differ across the MR series can check our high-index lens materials guide, and anyone weighing 1.67 resin against a higher-index option may find the thickness and weight trade-offs covered in our piece on when high-index lenses are worth it helpful for that separate decision.
What can be said about chipping at drill holes?
The claim that CR-39 or 1.67 resin chips more easily at drilled mounting points than MR-8 or polycarbonate is a reasonable-sounding idea, but it isn't backed by the evidence we have. For frames like semi rimless glasses, a grooved or drilled edge alters stress distribution compared to an unmodified edge, since material is removed and a load-bearing point is created. That much is a basic point about geometry, not a verified statement about how any specific lens material responds at that point over time.
What we don't have is a direct, publishable source measuring chip rates or fracture behavior at drilled holes across these specific materials. General impact-resistance ratings for a material describe how it handles a blow across its surface, not how it behaves at a drilled, load-bearing edge. Treat the two as separate questions until a source addresses the drilled-edge case directly, rather than assuming a material's overall toughness automatically predicts its drill-hole performance.
What to confirm before ordering rimless lenses
Since neither material comparison nor the chipping claim is settled by available evidence, your safest path is confirming the specifics of your own order rather than relying on a material label alone.
- Identify the exact lens material on your order, not just a category name like "resin" or "high-index." Ask for the specific product name, such as MR-8 or a named polycarbonate lens.
- Confirm mounting compatibility by asking whether that exact lens, with its chosen coatings, is approved for drilling or the supra (semi-rimless) groove method used on your frame.
- Check prescription and frame limits. Strong prescriptions, unusual frame shapes, or certain coatings can change which materials a lab will drill, so ask before you finalize the order.
- Pause if anything is unconfirmed. If your provider can't confirm the exact material and its mounting compatibility for your frame, ask before checkout rather than assuming the label guarantees fit.
Our order instructions page walks through the steps for specifying lens options and prescription details when you're ready to move forward.
FAQs
Is MR-8 or polycarbonate better for rimless glasses?
The evidence available to us doesn't establish either material as better for rimless or semi-rimless glasses. Both are commonly used in drill-mount frames, but we don't have a direct, publishable comparison of their performance at drilled points. Before ordering, confirm the exact material and its mounting compatibility with your frame and prescription with your eyewear provider.
Do CR-39 and 1.67 lenses chip more easily when drilled?
Published evidence does not verify that CR-39 or 1.67 resin chips more frequently at drill holes than polycarbonate or MR-8. While drilling creates stress points, verified fracture comparisons across these materials for rimless mounting are unavailable.
Does Trivex performance prove MR-8 or polycarbonate durability?
No. Manufacturer information from PPG identifies Trivex as well suited for rimless and semi-rimless styles, but that description applies only to Trivex and cannot be transferred to MR-8 or polycarbonate.
