Optical Detection

Four ways that astronomers can detect extrasolar planets are by radial velocity, astrometry, transit method, and optical detection.

In optical detection you can block out the star's glare using a physical mask called a coronograph. The cornograph hides everything except for the stars corona so you can see the other planets.
I have looked over many websites and I have not found any information that tells me how many extrasolar planets have been found through optical detection. I honestly cannot really even find anything about optical detection.