If you have a strong prescription, choosing the right lens material can make a big difference in comfort, appearance, and vision quality. High index lenses are thinner and lighter than standard lenses, and two of the most popular options are 1.67 and 1.74 high index lenses. But what’s the difference? And which one should you choose?
In this blog, we’ll explore the key features, benefits, and considerations of 1.67 and 1.74 high index lenses to help you make an informed decision.
What Are High Index Lenses?
High index lenses are made from materials that bend light more efficiently than traditional plastic or glass lenses. This allows the lenses to be thinner and lighter while still providing the correct prescription strength. The “index” number (such as 1.67 or 1.74) refers to the refractive index—the higher the number, the thinner the lens can be for the same prescription.
1.67 High Index Lenses
Who are they for?
1.67 lenses are designed for medium to high prescriptions, typically between ±3.00 and ±6.00 diopters.
Benefits:
Up to 35% thinner than standard 1.5 lenses
Lightweight and comfortable to wear
Less visible lens edge in frames compared to standard lenses
Usually more affordable than 1.74 lenses
Compatible with most frame types
Considerations:
Thicker and heavier than 1.74 lenses for very strong prescriptions
Slightly less impact resistant than 1.74
1.74 High Index Lenses
Who are they for?
1.74 lenses are the thinnest and lightest available for very high prescriptions, typically above ±6.00 diopters.
Benefits:
Up to 40% thinner than standard 1.5 lenses
Extremely lightweight for maximum comfort
Minimal lens edge thickness, ideal for rimless or semi-rimless frames
High impact resistance and durability
Superior cosmetic appearance, especially with very strong prescriptions
Considerations:
More expensive than 1.67 lenses
Not always necessary for prescriptions below ±6.00
Slightly less available in some lens brands or coatings
Comparison Table: 1.67 vs 1.74 High Index Lenses
| Feature | 1.67 High Index | 1.74 High Index |
|---|---|---|
| Prescription Range | Medium to high (±3.00 to ±6.00) | Very high (±6.00 and above) |
| Thickness Reduction | Up to 35% thinner than 1.5 | Up to 40% thinner than 1.5 |
| Weight | Lightweight | Ultra-lightweight |
| Edge Visibility | Reduced edge thickness | Minimal edge thickness |
| Frame Compatibility | Most frames | Best for rimless & semi-rimless |
| Impact Resistance | Good | Excellent |
| Cost | Moderate | Higher |
Which Should You Choose?
If your prescription is between ±3.00 and ±6.00, 1.67 lenses usually offer the best balance of thickness, weight, and cost.
For prescriptions stronger than ±6.00, 1.74 lenses provide the thinnest, lightest lenses with the best cosmetic appearance.
If budget is a key factor and your prescription is moderate, 1.67 lenses are often the preferred choice.
For those who wear rimless or semi-rimless frames, 1.74 lenses can be particularly advantageous due to their thin edges.
Additional Tips
Consider premium coatings like anti-reflective, scratch-resistant, and blue light filtering to enhance comfort and durability.
Always consult with your optician to assess your prescription, frame choice, and lifestyle needs before making a decision.
Remember, lens thickness can also depend on your specific prescription type (sphere, cylinder, and axis), not just the index.
Choosing between 1.67 and 1.74 high index lenses comes down to your prescription strength, frame style, budget, and personal preferences. Both lens types offer significant benefits over standard lenses, including reduced thickness, lighter weight, and improved appearance.
If you’re unsure which is best for you, speak with your eyewear professional — we can help recommend the perfect lenses to suit your needs.
