I think the white stuff you can see inside the eye is part of the skin surrounding the eyeball. Try getting some saline solution and rinsing his eyes a couple times a day.
It is better if you can remove the screen between bulb and dragon, I mount my UVB inside the cage so I didn't have to cut the screen.
Did the vet give you those eye drops for the white stuff? If not then don't. Wash the eye out with the plain solution- then give the drop medication. This way you will not wash out the medicine he needs