Here's an old and rather sketchy pic I once did which hopefully illustrates what I mean even though it's a bit lacking in detail and obviously a different style to what you're trying to achieve...
The lenses will usually have a saturated reflection at the top which is often a cooler colour, in this case I used green but blue reflections are a little more common. And underneath the frames at the bottom you see the darker shadow curving away with the form of the face and just above this shadow you see some contrasting light which gets focused onto the skin through the lens and in this case I used a saturated orange.
Intense light usually comes with this kind of saturated fringe and using it in this way can give that sense of glare that often accompany lenses and other optical effects.
And if you struggle to paint it directly then painting the light/reflections on a separate layer set to Screen or Colour Dodge can give you a bit more control.