When you make decisions about which contact lens brand you wear, you’re also making a decision about the type of material you’re putting in your eye. At Waldo, we use a high-quality material called Etafilcon A. This is a well-known hydrogel material which is newer than the popular alternative, Methafilcon A. As it turns out, there are some key differences between these materials which are worth paying attention to.
Below, we’ve lifted the lid on the 4 differences between these lens materials.
- DK/t (oxygen permeability):
Etafilcon A has a DK/t of 25, while Methafilcon A has a DK of just 18. An oxygen transmissibility (DK/t) of 21 is needed in order to prevent any ocular changes to the eyes.
- Water Content:
Etafilcon A has water content of 58%, while Methafilcon A has 55% water content. Water moisturizes the lens, it makes them softer and generally more comfortable to wear.
The FDA Group of Etafilcon A is 4. Methafilcon A is also 4, so there is no difference here.
Etafilcon A is a newer material and is more widely used, in comparison to Methafilcon A which is an older material and less popular as a lens material. Despite this, certain brands in the UK still use this material. Therefore, in order to protect your eye health we recommend checking exactly which type of contact lens you’re putting in your eyes on a daily basis.