If your lenses have the wrong diameter or base curve, you'll likely feel that something is always in your eye. If the lenses are too flat, your eyelids will tend to dislodge them when you blink. The wrong size lenses can even cause an abrasion of your cornea.
What base curve should I choose?
The most basic rule is that you always want the base curve to be as close to +6.00 as you can get and still have the Rx work. ... The more minus the power (less plus power to minus power) the lower plus the base curve will become. A high minus Rx may even have a base curve of +0.25 or even 0.00.
How important is base curve in contacts?
It determines the type of fit the lens must have to match the natural curvature of your eye. ... A person with a higher base curve number has a flatter cornea (the clear, front surface of the eye) compared to someone with a lower base curve number, which indicates a steeper cornea.