Contact Lens Base Curve Guide: How to Choose 8.6, 8.7, or 8.8

When you're shopping for contact lenses, you'll often see numbers like 8.6, 8.7, or 8.8 on the packaging. This is the base curve (BC), a measurement that determines how the lens curves to match your eye's shape. Getting it right is essential for comfort, clear vision, and eye health.

In this buying guide, we'll explain what base curve means, how to find yours, and how to choose between common sizes like 8.6, 8.7, and 8.8. Whether you're new to contacts or just curious about your fit, this guide will help you make an informed decision.

What Is Base Curve and Why Does It Matter?

The base curve is the radius of the inner surface of a contact lens, measured in millimeters. It determines how tightly or loosely the lens sits on your eye. A smaller number (like 8.6) means a steeper curve, while a larger number (like 8.8) means a flatter curve.

If the base curve is too steep, the lens may pinch your eye, causing discomfort and redness. If it's too flat, the lens may move too much, leading to blurred vision or a feeling that the lens is about to fall out. A proper fit ensures the lens stays centered and allows your eye to breathe.

• Base curve is typically measured in millimeters (mm).
• Common values for soft contact lenses range from 8.0 to 9.0.
• Your eye care professional will measure your corneal curvature to determine the right base curve.

How to Find Your Base Curve

The most reliable way to know your base curve is to check your contact lens prescription. It's usually listed as 'BC' or 'Base Curve' followed by a number like 8.7. If you don't have a prescription, you'll need an eye exam where your optometrist measures your cornea using a keratometer or topographer.

Never guess your base curve. Wearing lenses with the wrong base curve can lead to corneal abrasions, infections, or poor vision. If you're ordering online, make sure you have your prescription handy and match the base curve exactly.

• Look for 'BC' on your lens box or prescription.
• If you're between sizes, your eye doctor will recommend the best fit.
• Some brands offer lenses in only one base curve, so check the specifications.

8.6 vs 8.7 vs 8.8: What's the Difference?

The difference between 8.6, 8.7, and 8.8 is subtle—just 0.1mm—but it can affect how the lens feels. An 8.6 base curve is steeper and may suit eyes with a more curved cornea. An 8.8 is flatter and better for eyes with a less curved cornea. 8.7 is a middle ground that fits many people.

Most soft contact lenses on the market have a base curve between 8.4 and 8.8. Brands like our store offer options in 8.6, 8.7, and 8.8 to cater to different eye shapes. For example, the WCX-720 DEWY BROWN comes in an 8.7 base curve, which is a popular choice for its natural look and comfortable fit.

When choosing, always follow your prescription. If your doctor recommends 8.7, don't opt for 8.6 or 8.8 without consulting them. A wrong base curve can cause the lens to move excessively, leading to dry eyes or blurred vision.

• 8.6: steeper curve, for more curved corneas.
• 8.7: intermediate, fits many wearers.
• 8.8: flatter curve, for less curved corneas.

How to Choose the Right Base Curve for Your Eye

Your eye care professional is the best person to determine your base curve. However, if you're buying lenses online and already have a prescription, you can use it to filter products. For instance, if your BC is 8.7, look for lenses like the WCX-579 DAHLIA WILD HONEY, which offers a beautiful honey tone with that base curve.

Remember that base curve is just one part of the fit. The lens diameter (DIA) also matters, as we covered in our guide on choosing the right diameter. Together, these measurements ensure the lens aligns with your eye's shape.

If you're unsure, many online stores have customer support that can help you check if a lens matches your prescription. Don't hesitate to ask before purchasing.

• Always match the base curve on your prescription.
• Consider the lens material and water content for comfort.
• If you experience discomfort, have your eyes re-evaluated.

Common Base Curve Mistakes to Avoid

One common mistake is assuming that a higher base curve is always more comfortable. In reality, a lens that is too flat can cause the edges to lift, leading to irritation and poor vision. Similarly, a lens that is too steep can suction onto the eye, making removal difficult.

Another mistake is buying lenses with a different base curve than prescribed because a certain color is only available in another size. For example, if you love the grey look of the WCX-605 TOAST SESAME GREY but it doesn't come in your base curve, it's better to choose a different style that fits properly than to compromise your eye health.

Always prioritize fit over aesthetics. Your eye health is more important than a specific shade or pattern.

• Don't swap base curve for color.
• Don't ignore discomfort—it could signal a poor fit.
• Don't share lenses with others; base curve varies per person.

Base Curve Chart for Quick Reference

To help you visualize, here's a simple chart showing how base curve relates to eye shape:

• 8.6: Steep fit – for eyes with a more curved cornea (common in Asian eyes).
• 8.7: Standard fit – suits a wide range of eye shapes.
• 8.8: Flat fit – for eyes with a flatter cornea.

Final Tips for Buying Contact Lenses Online

When shopping online, always check the product specifications for base curve and diameter. If a lens doesn't list the BC, it's best to avoid it or contact the seller. Our store provides detailed specs for every lens, so you can easily filter by base curve.

Remember that your prescription may include a base curve that isn't exactly 8.6, 8.7, or 8.8. Some lenses come in 8.4 or 8.9 as well. If your prescription is unusual, you may need to explore different brands or consult your eye doctor for alternatives.

For daily wear, consider options like the XENA BROWN 1 DAY, which offers convenience and a natural brown look. Daily disposables eliminate the need for cleaning solutions and reduce the risk of infections, making them a great choice for beginners.

• Check the base curve and diameter on every product page.
• If you're between sizes, ask your eye doctor for advice.
• Consider daily lenses for hygiene and convenience.

Choosing the right base curve is crucial for comfortable and healthy contact lens wear. Always rely on your prescription and consult your eye care professional if you're unsure. Explore our range of lenses with various base curves to find your perfect match. For a convenient and natural option, check out the XENA BROWN 1 DAY, or browse our full collection to discover more styles that fit your needs.