According to Wiki – catch light or catchlight is a photography term used to describe either the specular highlight in a subject’s eye from a light source, or the light source itself.
Okay here’s my step by step guide on how to enhance the catchlight. It’s pretty straightforward.
Open the file in Photoshop
Select the Ellipse tool.
Choose white in your foreground color.
Create two circles, it should cover the irides of the eyes. I suggest you do it one at a time for eyes with different exposures and adjust accordingly.
Tip: press shift while doing this to make a perfect circle, and by pressing space bar, in addition to shift and left click, you can actually reposition that circle.
Blur the shape layer using the gaussian blur under filter. A message will prompt that you have to rasterize the shape layer, just click ok. The blur value actually depends on your image, I’ll leave that decision to your taste but in this photo I used 8.0.
By now, your circles should be the same as the photo below.
Then we’ll be changing the composite mode of the layer to Overlay – you can find it on top of layer tab.
You’ll definitely have spills from the circles so the next thing will be erasing those spills – Erase tool (E). Make sure that your brush hardness value is soft enough to erase the spills unobviously.
Finally, let’s make it natural. Change the opacity of the shape layer, I brought down the opacity to 70%.
Again, the value depends on the image so I’ll leave this to your creative taste as well.
Additional tip: you can actually use this trick to any reflection.