Guang Ming is a point on the Kidney channel that you may know from TCM school as Kidney 7. This is a nice point to use for eye problems (conjunctivitis, for instance) among other things. You will find it 2 cun proximal to Kidney 3.
Note that some references put it 1 cun proximal to Ki 3, which would mean it is between Kidney 3 and Kidney 7.