Base Curve (BC) of Colored Contact Lenses | The Key Code to Wearing Comfort
Guys, today let's talk about a parameter that is extremely important but easily overlooked when choosing colored contact lenses - the base curve.
What is the base curve of colored contact lenses?
The base curve (Base Curve, abbreviated as BC) of colored contact lenses refers to the curvature of the inner surface of the lens, which determines the degree of fit between the lens and the surface of the eyeball. The base curve values (such as 8.4mm, 8.6mm) represent the degree of curvature of the lens. The larger the value, the flatter the lens; the smaller the value, the more curved the lens is.
The Impact of the Base Curve on the Wearing Experience
If the base curve of the colored contact lenses is not appropriately selected, various problems will occur when wearing the colored contact lenses. If the base curve is too large and the lens is too flat, the lens will slide on the eyeball, resulting in unstable vision and blurry vision. Moreover, it is also prone to lens displacement, affecting both the appearance and comfort. If the base curve is too small and the lens is too curved, the lens will stick tightly to the eyeball, hindering the normal metabolism of the eyeball. The eyes will feel very dry and have a foreign body sensation. Wearing it for a long time may also cause harm to the eyes.
Only by choosing colored contact lenses whose base curve matches the eyeball can the lens naturally fit the eyeball, have a moderate range of movement, and at the same time reduce the risk of complications.
How to Determine the Base Curve Suitable for Yourself
1. Measurement in a Hospital or Professional Institution: The most accurate way is to go to the ophthalmology department of a hospital or a professional optical store and let a doctor or an optometrist use professional instruments to measure the curvature of your cornea, so as to obtain the base curve value suitable for you. Generally speaking, there is a conversion formula for the base curve corresponding to the corneal curvature, but professionals will take care of it for you.
2. Refer to Past Wearing Experience: If you have worn colored contact lenses before and felt comfortable, you can check the base curve value marked on the packaging of the previously purchased colored contact lenses and use it as a reference. However, it should be noted that even if the base curve values of colored contact lenses of different brands are the same, the actual wearing experience may still vary.
3. Try colored contact lenses with different base curves. For those who are wearing colored contact lenses for the first time, it is difficult to choose the appropriate base curve of colored contact lenses, but they may also find it troublesome to ask an optometrist to measure the corneal curvature. Therefore, I suggest purchasing trial packs first, trying colored contact lenses with different base curves, and finding out the base curve of colored contact lenses that is most suitable for your eyes.
Small Suggestions for Choosing the Base Curve of Colored Contact Lenses
1. Novices should choose a moderate base curve: For those who are just starting to wear colored contact lenses, it is recommended to choose products with a base curve of about 8.6mm - 8.7mm. This range is relatively moderate and suitable for the eyeballs of most people.
2. Pay attention to the brand instructions: There may be some differences in the base curve design of colored contact lenses of different brands. When purchasing, be sure to carefully read the product introduction and instructions to understand the characteristics of the base curve of the colored contact lenses of this brand and the applicable population.
3. The try-on experience is very important: If you have the opportunity to try them on, you must seriously feel the comfort after wearing them. If you feel that the lens slides obviously or feels too tight, it means that this base curve may not be suitable for you.
Tips: Even if the base curve is suitable, it is recommended that the daily wearing time should not exceed 8 hours, and the cleaning process should be strictly followed!
Guys, only by choosing the right base curve of colored contact lenses can we have beautiful eyes while ensuring the health and comfort of our eyes. I hope today's sharing will be helpful for you to choose colored contact lenses.
