Lens Thickness Comparison: Standard vs High Index vs Ultra Thin
Choosing the right lens material can dramatically change how your glasses look, feel, and perform. This lens thickness comparison highlights the real differences between standard plastic lenses (CR-39), polycarbonate lenses, 1.60 high-index lenses, and 1.67 ultra-thin lenses across common prescriptions like -2.00, -4.00, and -6.00. You’ll see how polycarbonate offers a thinner, impact-resistant alternative to standard plastic, while high-index materials like 1.60 and 1.67 provide even slimmer profiles for stronger prescriptions. If you’re wondering whether polycarbonate or high-index lenses are worth it for your prescription, this guide will help you make a confident, informed decision.
What Determines Lens Thickness?
Lens thickness depends on four main factors:
- Your prescription strength
- Lens material (standard vs high index)
- Frame size
- Frame shape
Stronger prescriptions bend light more aggressively, which increases edge thickness - especially for minus (-) prescriptions. That is why thin lenses for stronger prescriptions are often recommended.
Lens Thickness Comparison by Prescription Strength
Below is a simple comparison to help you understand how thickness changes depending on lens material. Exact results vary by frame size, shape, and your prescription details.
Lens Material Thickness Guide
Standard Plastic (1.50)
- Thicker edges
- Heavier compared to higher index materials
- Best suited for lower prescriptions
- Budget-friendly option
Polycarbonate (1.59)
- Thinner than standard plastic
- Lightweight
- Highly impact resistant
- Good balance between durability and thickness
High Index 1.60
- Noticeably thinner than polycarbonate
- Lighter weight
- Sleeker cosmetic appearance
- Good upgrade for moderate prescriptions
High Index 1.67
- Ultra-thin profile
- Lightest feel for stronger prescriptions
- Best cosmetic improvement among these four materials
- Recommended for higher prescriptions
Recommendation:
For prescriptions around −6.00 (or +6.00), 1.67 high index lenses provide the best balance of comfort,
thinness, and cosmetic appearance within these material options.
High Index Lens Thickness Chart Overview
Exact thickness varies by frame size, lens shape, and pupillary distance (PD). However, this comparison provides a realistic overview of how plastic, polycarbonate, and high index lenses differ.
General rule:
- Up to ±2.00 — Standard Plastic or Polycarbonate is usually fine
- ±2.00 to ±4.00 — High Index 1.60 is often recommended
- ±4.00 and above — High Index 1.67 is usually the best cosmetic choice
Standard vs High Index Lenses — What Is the Real Difference?
Higher index lenses bend light more efficiently. This allows the same prescription to be made with less material.
Resulting benefits:
- Thinner edges
- Reduced weight
- Better balance on your nose
- Cleaner appearance, especially in larger frames
The prescription strength does not change — only the lens thickness and weight improve.
Who Should Upgrade to High Index Lenses?
Consider upgrading if:
- Your prescription is stronger than ±3.00
- You wear large or wide frames
- You want a thinner, lighter look
- You dislike thick lens edges
- You wear rimless or semi-rimless frames
For moderate to strong prescriptions, high index lenses are typically worth the upgrade.
Does Frame Size Affect Lens Thickness?
Yes — significantly.
Large rectangular frames usually increase visible edge thickness. Smaller or rounder frames typically reduce edge thickness.
Lens material and frame size work together, so both should be considered before ordering.
1.60 vs 1.67 — Is There a Big Difference?
Both are high index materials, but they are not identical:
- 1.60 = Thin
- 1.67 = Ultra thin
The difference becomes more noticeable as prescriptions increase beyond ±4.00. For mild prescriptions, the visual difference may be subtle. For stronger prescriptions, the difference can be significant.
Frequently Asked Questions
Are high index lenses stronger?
No. They simply use a denser material that bends light more efficiently.
Do thinner lenses affect clarity?
No. Optical clarity remains excellent when properly manufactured.
Is polycarbonate stronger than other materials?
Polycarbonate is highly impact resistant, making it ideal for active lifestyles, kids, and rimless frames.
Do I need high index for −2.00?
Not necessarily — unless you prefer a thinner cosmetic profile.
Final Tip Before You Order
If you are unsure which lens index to choose, start with your prescription strength and frame size. Stronger prescriptions and larger frames benefit the most from high index materials. Choosing the right lens material improves comfort, appearance, and long-term satisfaction.