Creating a "bubble" shape lense for goggles I have made these spiderman styled goggle frames for a project I am working on, after modelling the frames I duplicated the inner edge of the goggle frames, split to a new layer and then inset this selection a few times and adjusted each inset edge loop to create a more pronounced curve shape for the lense. My question is if there is a way of making the bubble effect a little more pronounced, clean and even in curvature? I first attempted to add a sphere and distort to fit the shape of the frame but this looked worse than my current attempt which is the one I have attached.
If you have a nice number of vertices in the perimeter ( I think you do.. 12 on each side of the triangle?)

Then:


One inset
Delete inner face, and select new perimeter
CtrlF (Face Menu) > 'Grid Fill'..




.. can give you a nice topology, in which you can select a central vertex, and 
 O Proportionally Edit it. Set the Transform Orientation to 'Normal', and GZZ bulge the vertices outwards.

If you need to conform to existing geometry, you can hide the outer edge-ring (blue in the picture) while you're doing the proportional edit.

If when you unhide the outer ring the transition is too sharp, you can select  all but the vertices on the perimeter and  CtrlV > 'Vertex Smooth' them.