What are the risks to wearing contacts with a base curve slightly larger than original?

Contact stability: The base curve of a contact lens indicates its curvature relative to the surface curvature of the eye. If steeper, the lens may hug tightly and become uncomfortable. If larger (less steep) there may be a tendency for the lens to ride out of position. An optimum fit will be stable, comfortable, and give good vision. You ophthalmologist can do this.

Poor CL fit: A slightly larger base curve can cause the cl to move differently in most cases. The ophthalmologist fitting you can compensate for this by changing the cl diameter.

Corneal ulcer: You can have disruption of the surface of your eye if you have the wrong contact lens in your eye. Think of wearing the wrong size shoe for awhile. It is not recommended.