What is lens index? When it comes to getting new glasses, most people focus on the frame. But the lenses—and more specifically, their index—play a huge role in how your glasses look, feel, and perform.
Whether you’re looking for the thinnest possible lens or trying to balance cost and comfort, this guide will help you understand what lens index is, how to choose the right one, and what you can expect in terms of price.
What Is a Lens Index?
The lens index, or refractive index, measures how efficiently a lens material bends (or refracts) light. The higher the index, the thinner the lens can be while still correcting your vision accurately.
➕ Higher index = thinner, lighter lenses
➖ Lower index = thicker lenses, especially for strong prescriptions
Lens Index Types & Detailed Comparison
1.50 Index (Standard/CR-39 Plastic)
- Best for: Prescriptions up to ±2.00
- Pros: Inexpensive, durable, good optical clarity
- Cons: Thick and bulky for stronger prescriptions
1.56 Index (Mid-Index)
- Best for: Prescriptions up to ±3.00
- Pros: Slightly thinner than 1.50, still budget-friendly
- Cons: Not suitable for high prescriptions
1.61 Index (High-Index)
- Best for: Prescriptions between ±2.00 to ±4.00
- Pros: Lighter and thinner than 1.50/1.56, good balance of cost and appearance
- Cons: Slightly higher cost than standard
1.67 Index (Super High-Index)
- Best for: Prescriptions between ±4.00 to ±6.00
- Pros: Up to 30% thinner than 1.50, looks more aesthetic for higher prescriptions
- Cons: Less impact-resistant, more expensive
1.74 Index (Ultra High-Index)
- Best for: Prescriptions above ±6.00
- Pros: The thinnest and lightest available, ideal for strong prescriptions and high minus powers
- Cons: Highest cost, more reflective without quality coatings
Lens Thickness Comparison Chart
| Lens Index | Ideal Prescription Range | Relative Thickness | Weight | Cost | Best For |
|---|---|---|---|---|---|
| 1.50 | 0 to ±2.00 | Thickest (100%) | Heaviest | $ | Budget, low prescriptions |
| 1.56 | 0 to ±3.00 | ~85% of 1.50 | Medium | $$ | Slightly stronger Rx |
| 1.61 | ±2.00 to ±4.00 | ~75% of 1.50 | Light | $$$ | Daily wear, moderate Rx |
| 1.67 | ±4.00 to ±6.00 | ~65–70% of 1.50 | Lighter | $$$$ | High Rx, aesthetics |
| 1.74 | ±6.00 and above | ~50–55% of 1.50 | Lightest | $$$$$ | Ultra-thin, strong prescriptions |
How to Choose the Right Lens Index for Your Prescription
| Prescription | Recommended Lens Index | Why? |
|---|---|---|
| 0 to ±2.00 | 1.50 or 1.56 | Affordable, no need for thin lenses |
| ±2.00 to ±3.00 | 1.56 or 1.61 | Thinner, more comfortable |
| ±3.00 to ±4.00 | 1.61 or 1.67 | Balanced between aesthetics and cost |
| ±4.00 to ±6.00 | 1.67 | Reduces lens bulge, looks sleeker |
| Above ±6.00 | 1.74 | Best thinness, reduces lens weight dramatically |
💡 Tip: The higher your prescription, the more you’ll benefit from higher index lenses for better comfort and appearance—especially for minus (nearsighted) powers.
Current Price Guide by Lens Index (Based on General Market Ranges)
Prices vary depending on lens brand, coatings, and whether they’re single vision, progressive, or blue-light blocking. Here’s a rough guide for single vision lenses with basic anti-glare:
| Lens Index | Estimated Price (Per Pair) |
|---|---|
| 1.50 | RM100–RM200 |
| 1.56 | RM180–RM250 |
| 1.61 | RM250–RM380 |
| 1.67 | RM400–RM550 |
| 1.74 | RM600–RM850+ |
🛍️ Some brands like Essilor, ZEISS, Hoya, and Tokai offer custom packages with premium coatings, UV protection, and blue light filters—this will increase the price but improve durability and comfort.
Summary: Which Index Is Best for You?
- Low Prescription (±0 to ±2): Save money with 1.50 or 1.56
- Moderate Prescription (±2 to ±4): Opt for 1.61 for better clarity and thinner lenses
- High Prescription (±4 to ±6): Consider 1.67 for lightweight, more aesthetic lenses
- Very High Prescription (Above ±6): 1.74 is worth the investment for ultra-thin lenses
Final Word
Choosing the right lens index is about balancing appearance, comfort, and budget. While higher index lenses come at a premium price, they can make a huge difference in how your glasses look and feel—especially if you wear them every day.
Always consult your optometrist to make sure you’re choosing the right combination of lens material, index, and coatings for your vision needs and lifestyle.
Book an appointment with our qualified optometrist today to learn more.