Catch light is a term used to describe the light in a person’s eyes, which can be used to draw attention to them
Create a duplicate of the Background layer by going to Layer>Duplicate Layer. Hit OK in the pop-up box to place a new layer in the Layers palette.
Select your Brush tool (press B) and set its Diameter to 20px and Hardness to 50%. Find these settings under Brush in the Options bar.
The Mode in the Options bar needs to be set to Overlay, and the Opacity can be reduced down to 50%. Make sure your foreground colour is set to white.
Zoom in up close to the eyes and run the Brush tool over the top of the pupils. Because the tool is set to Overlay, any details will look blown out if you paint too heavily with the tool. It’s worth lowering the Opacity of the tool to 30% or below. Look to create similar a catch light for both eyes.