Lens Materials. ABBE Values, & Index of Refraction
Memorize this chart, it will not only help you with test questions but help dispense the correct material for a patient.
Remember that the higher the ABBE Value the less chromatic aberrations in a lens.
The Higher the Index of Refraction, the less material is needed in a lens to refract light so the thinner it will be.
| Material | ABBE Value | n |
| Crown Glass | 58 | 1.52 |
| CR39 | 58 | 1.49 |
| Polycarbonate | 31 | 1.59 |
| Trivex (Mid-Index) | Roughly 44 | 1.53 |
| Hi-Index Lenses | 31-42 (Depends on Index/Manufacturer) | 1.60, 1.67, 1.70, 1.74 |
| Diamond | 22.73 | 2.4 |
| Water | 1.33 | |
| Flint Glass | Roughly 52.5 | 1.66 |
🧪 Lens Materials Overview
1. CR-39 (Standard Plastic)
Refractive Index: 1.498
Abbe Value: 58–59
Density: 1.31 g/cm³
UV Protection: Blocks up to 355 nm
Patient Benefits:
Excellent optical clarity with minimal chromatic aberration.
Lightweight and comfortable for daily wear.
Cost-effective option for budget-conscious patients.
Naturally more scratch-resistant than other plastics.
Recommended Use:
Ideal for patients with low to moderate prescriptions.
Suitable for standard full-frame eyeglasses.
Not recommended for rimless or semi-rimless frames due to lower impact resistance.
2. Polycarbonate
Refractive Index: 1.586
Abbe Value: 30
Density: 1.20 g/cm³
UV Protection: Blocks up to 385 nm
Patient Benefits:
High impact resistance—up to 10 times more than CR-39.
Lightweight and thinner than standard plastic lenses.
Inherent UV protection without additional coatings.
Suitable for active lifestyles and children's eyewear
Recommended Use:
Excellent for children, athletes, and safety glasses.
Preferred for rimless and semi-rimless frames due to durability.
Not ideal for patients sensitive to chromatic aberrations due to lower Abbe value.
3. Trivex
Refractive Index: 1.532
Abbe Value: 43–45
Density: 1.11 g/cm³ (lightest available)
UV Protection: Blocks up to 394 nm
Patient Benefits:
Combines high impact resistance with superior optical clarity.
Ultra-lightweight for enhanced comfort.
High tensile strength—ideal for drill-mounted frames.
Inherently blocks 100% of UV rays.
Easily tintable for customized lens options. VisionPlus Magazine+9Laramy-K Independent Optical Lab
Recommended Use:
Preferred for rimless and semi-rimless frames due to resistance to cracking.
Suitable for patients with moderate prescriptions seeking clarity and durability.
Ideal for safety eyewear and active lifestyles.
4. High-Index Plastics (1.60–1.74)
Refractive Index: 1.60–1.74
Abbe Value: 32–42 (varies by index)
Density: 1.3–1.5 g/cm³
UV Protection: Blocks up to 400 nm
Patient Benefits:
Thinner and lighter lenses for high prescriptions.
Improved aesthetics due to reduced lens thickness.
Inherent UV protection.
Recommended Use:
Ideal for patients with high prescriptions (above ±4.00).
Suitable for fashionable, lightweight frames.
Not recommended for patients sensitive to chromatic aberrations due to lower Abbe values.
🏆 Why Trivex is Our Preferred Material
At OpticianStudy.com, we favor Trivex lenses for several compelling reasons:
Exceptional Clarity: High Abbe value ensures minimal chromatic aberration.
Superior Durability: High tensile strength makes it resistant to cracking, especially in drill-mounted frames.
Lightweight Comfort: Lowest density among lens materials for all-day wear.
Versatility: Suitable for a wide range of prescriptions and frame styles.
UV Protection: Blocks 100% of harmful UV rays without additional coatings
Lens Material Recommendations for Minus Prescriptions (Myopia)
| Prescription Range | Recommended Materials | Reason |
|---|---|---|
| 0 to -2.00 D | CR-39, Trivex, Polycarbonate | Minimal edge thickness; budget-friendly. |
| -2.00 to -4.00 D | Trivex, Polycarbonate, 1.60 High Index | Thinner than CR-39 with good durability and optics. |
| -4.00 to -6.00 D | 1.60 or 1.67 High Index, Polycarbonate | Noticeable reduction in edge thickness. |
| -6.00 D and above | 1.67 or 1.74 High Index | Minimizes lens weight and thickness in high myopia. |
Lens Material Recommendations for Plus Prescriptions (Hyperopia)
| Prescription Range | Recommended Materials | Reason |
|---|---|---|
| 0 to +2.00 D | CR-39, Trivex | Center thickness is moderate with good optics. |
| +2.00 to +4.00 D | Trivex, 1.60 High Index | Reduces center thickness for comfort and cosmetics. |
| +4.00 D and above | 1.67 or 1.74 High Index | High plus lenses benefit from thinner, lighter options. |
Frame-Specific Material Recommendations
| Frame Type | Recommended Materials | Reason |
|---|---|---|
| Rimless or Semi-Rimless | Trivex, Polycarbonate | High impact resistance; durability for drill mounts. |
| Full Frame | All materials suitable depending on Rx | CR-39 acceptable for low Rx; high index for strong Rx. |
Note: Trivex offers excellent optical clarity and strength with a lightweight feel, making it our top recommendation for most moderate prescriptions and rimless frame designs.