Lens Fitting - Base Curve and Diameter

When you browse cosmetic or special‑effects lenses on FashionLens.nz, you’ll often see fitting information such as:

B.C: 8.6mm
DIA: 15mm

These numbers help describe the shape and size of the lens. They’re not medical prescriptions - they’re simply standard measurements used across the contact lens industry so customers know what to expect when choosing cosmetic lenses.

This page breaks down what these terms mean and how they relate to comfort and fit.

What “B.C.” (Base Curve) Means

B.C. stands for Base Curve, which describes how curved the back surface of the lens is.

• A lower number = a steeper curve
• A higher number = a flatter curve

Most cosmetic lenses worldwide use a base curve of 8.6mm, which fits the majority of wearers comfortably.

Important:
Base curve is not a medical prescription. Cosmetic lenses are designed with a “one size fits most” approach, which is why nearly all brands use 8.6mm.

If you ever experience discomfort, remove the lens immediately and clean/store it properly before trying again.

What “DIA” (Diameter) Means

DIA stands for Diameter, which is the total width of the contact lens from edge to edge. The diameter affects how much of your eye the lens covers and how dramatic the final look will be.

Here’s a simple breakdown:

• 14.0–14.5mm > natural‑looking colour lenses
  These sizes mimic the natural iris and are ideal for everyday wear or subtle enhancements.
• 15–17mm > larger, more dramatic, or special‑effects lenses
  These create a bigger‑than‑natural eye appearance, often used for anime, doll‑eye, or fantasy looks.
• 17mm > “mini sclera” lenses
  These cover more of the eye than standard cosmetic lenses, extending past the iris for a bold, intense effect. Mini scleras are popular for horror, demons, and creature transformations because they instantly change the eye shape and presence. They are a bit more difficult then standard lens to put in.
• 22mm > full sclera lenses
  These are the largest cosmetic lenses available and cover the entire visible part of the eye, including the sclera (the white area). Full sclera lenses create the most extreme transformation possible - perfect for high‑impact horror characters, film shoots, and advanced cosplay.
  Because they cover so much of the eye, they require more care, patience, and experience to insert and remove. They’re not recommended for beginners.

Why These Measurements Matter

These measurements help you understand:

• How dramatic the lens will look
• How much of your eye the lens will cover
• What level of comfort to expect
• Whether the lens is a standard cosmetic size or a special‑effects design

Mini sclera lenses (17mm) are more noticeable when worn, but many cosplayers prefer them because they create a stronger transformation.

Are These Measurements Safe?

Cosmetic lenses sold in New Zealand must meet international manufacturing standards.
The measurements do not indicate risk — they simply describe the lens design. If you have any concerns at all please visit your local eye specialist.

What This Means for FashionLens.nz Customers

When you see B.C 8.6mm / DIA 15mm on a product page, it simply means:

• The lens uses the standard cosmetic base curve used by most global brands
• The lens is designed for cosmetic use, not vision correction
• The fit is intended to be comfortable for most wearers when used correctly

If you’re new to cosmetic lenses, start with shorter wear times and always follow proper cleaning and storage instructions.