Q1: What causes contact lens slippage?
Contact lens slippage refers to the phenomenon where the lens does not adhere to the eyeball and slides inside the eye. The root cause of slippage is an unsuitable base curve of the lens. The base curve refers to the degree of curvature of the lens. Most human eyes have a base curve between 8.4 and 8.6, but some have as high as 8.8 or even 8.9, or as low as 8.3 or even 8.2.
Q2: How do I find out my base curve?
You can have it measured at an ophthalmology clinic/optician's. The doctor can convert the measurements on the spot. I highly recommend having your base curve measured for comfort!
Q3: How to choose the base curve of colored contact lenses?
Generally, a base curve difference of 0.2mm from the actual measured base curve is acceptable, but it's best to choose a larger one.
For example, if the measured base curve is 8.6, then a range of 8.4 to 8.8 is fine!
If the base curve of the lens differs too much from the curve of your eye, it's like wearing ill-fitting clothes, making it very easy for the lens to slip. In severe cases, the contact lens may slip out of the eye socket, even causing corneal damage. Therefore, when buying colored contact lenses, in addition to paying attention to the color and material, you must also pay attention to the base curve!
Q4: Besides the base curve, are there other reasons for contact lens slippage?
1. Lens worn inside out:
If you didn't experience slippage before, but it suddenly starts happening, it's likely that the contact lens is worn inside out. The friction between the lens and your eyeball causes slippage.
2. Tear secretion:
Some people have very sensitive eyes and find it difficult to wear contact lenses. The eyes automatically secrete tears to relieve discomfort and protect the eyeball. Excessive tears can cause the lens to slip, resulting in slippage.
3. Excessive contact lens solution residue:
If a large amount of contact lens solution remains on the lens, it can also cause slippage.
4. Lens too soft:
If the lens material is too soft or thin, the lens becomes unstable, which can also cause slippage.
