Original image

step 1 of 5

step 2 of 5

step 3 of 5
placed at the center of the pupil.

step 4 of 5
pen right-click mouse> Stroke Path> brush.
I previously placed the dynamics and dispersal of the brush, giving it a reddish color / gold.
for adjusting the brush just go to: Window> Brushes (F5) and adjust the distance or hardness you prefer.

step 5 of 5
.....and Finish^^

Final result

