Lighting Effects - The Photoshop: Professional Retouching and Compositing Tips, Tricks, and Techniques - page 195

Figure 3.38
8. The Inner Glow layer style now appears on its own layer at the top of the layer
stack. With this layer active, hold down Option/Alt and click the layer mask icon
at the bottom of the layer panel. This adds a black layer mask ( Figure 3.39 ) .