It is not recommended to wear contact lenses with a different diameter from your prescription. If the diameter is too wide, the lens will be loose in the eye and may slip out of place. If the diameter is too small, the lens will have a tight fit, causing discomfort.

What is the difference between 14.0 and 14.2 diameter contacts?

14.0mm and 14.2mm contacts

In fact, there is not much difference between these two. Some manufacturers only make 14.2mm diameter contacts, and some others produce 14.0mm diameter contacts. ... This is because they only choose one of these two small size contacts.

How important is the diameter on contact lenses?

It's very important because it shows in which part of your eye the edges of the contact lens will rest. If the diameter is wrong, too small or too large it wont be stable on your eye and move around too much or it can be too tight and cause eye irritation and corneal abrasions.