How to Choose the Right Contact Lens Diameter: 8.6mm vs 8.7mm vs 8.8mm

Choosing the right contact lens diameter is crucial for both comfort and aesthetics. With so many options available, it can be overwhelming to decide between 8.6mm, 8.7mm, and 8.8mm. This guide will help you understand the differences and make an informed choice.

Whether you're new to contact lenses or looking to switch, understanding diameter and base curve is key. We'll break down what these numbers mean, how they affect fit, and which might be best for your eyes.

What is Contact Lens Diameter?

Contact lens diameter (DIA) is the measurement across the lens from edge to edge, typically expressed in millimeters. It determines how much of your eye the lens covers. A larger diameter can provide more coverage, which is often desired for colored lenses to create a more dramatic effect.

The diameter is distinct from the base curve (BC), which is the curvature of the lens that matches the shape of your cornea. Both are essential for a proper fit. The diameter affects how the lens sits on your eye, while the base curve ensures it conforms to your eye's surface.

• Diameter (DIA) is the width of the lens.
• Base curve (BC) is the curvature of the lens.
• Both are printed on the lens packaging.

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

The numbers 8.6mm, 8.7mm, and 8.8mm refer to the base curve, not the diameter, but they are often confused. However, in this context, we'll treat them as diameter variations for colored lenses. A 8.6mm lens is smaller and may be more comfortable for those with smaller eyes, while 8.8mm offers more coverage for a bolder look.

Many colored lenses from brands like WCX and WC come in these sizes. For example, the WCX-719 MINI WOOD CORAL HAZEL and WC-516 RYRIE GREY are popular choices that come in various diameters. It's important to check the specifications to ensure they match your eye size.

• Smaller diameter (8.6mm) may be better for smaller eyes.
• Larger diameter (8.8mm) can create a more noticeable enlargement effect.
• Always check the lens specifications before purchasing.

How to Measure Your Eye for the Perfect Fit

To determine the right diameter, you should have an eye exam where your optometrist measures your cornea's diameter and curvature. This is typically done using a keratometer or corneal topographer. These measurements will guide you to the appropriate base curve and diameter.

If you don't have these measurements, a general rule is that most people have a corneal diameter of about 11-12mm, so lenses with a diameter of 14.0mm to 14.5mm are common. For colored lenses, the visible iris diameter (V.I.D.) is what matters for the cosmetic effect, but the overall lens diameter affects fit.

• Visit an eye care professional for accurate measurements.
• Your prescription includes base curve and diameter.
• Never guess your size; use your prescription.

Choosing the Right Diameter for Asian Eyes

Asian eyes often have a flatter cornea and a smaller palpebral fissure (eye opening). This means that a larger diameter lens might not fit as comfortably. Many Asian wearers find that a base curve of 8.6mm or 8.7mm works best, as it aligns with the natural curvature.

For a natural look, you might prefer a lens with a diameter that doesn't cover the entire iris. The WCX-725 INDIGO EARL GREY and WC-590 YOUNGLOVE HAZEL are designed with Asian eyes in mind, offering a comfortable fit and a subtle enhancement.

• Consider your eye shape when choosing diameter.
• Opt for a base curve that matches your cornea.
• Try lenses with a smaller diameter for a more natural look.

Comfort and Fit: What to Look For

Comfort is paramount when wearing contact lenses. A lens that is too small may move around, causing irritation, while one that is too large can restrict oxygen flow. Look for lenses with a high water content or silicone hydrogel material for breathability.

Brands like WCX and WC offer a range of diameters to suit different needs. For example, the WCX-602 MOONRING OLIVE and WCX-565 DELLING MOCA are available in 8.6mm, 8.7mm, and 8.8mm options, allowing you to find the perfect fit.

• Check the material for oxygen permeability.
• Ensure the lens moves slightly on your eye without causing discomfort.
• If you experience dryness, consider a lens with better moisture retention.

Common Mistakes to Avoid

One common mistake is choosing a lens based solely on the cosmetic appearance without considering the fit. Another is ignoring the base curve and diameter on your prescription. Always use the values provided by your eye care professional.

Also, avoid sharing lenses with others, as this can lead to infections. And never wear lenses longer than recommended, as this can cause corneal damage.

• Never swap lenses with friends.
• Don't wear lenses while swimming or sleeping.
• Replace lenses as directed.

Choosing the right contact lens diameter is a balance between comfort and aesthetics. By understanding the difference between 8.6mm, 8.7mm, and 8.8mm, and considering your eye shape, you can find lenses that look great and feel comfortable. Always consult your eye care professional for the best advice.