By taking into account relativistic corrections to the magnetic dipole operator , the theoretical [ OIII ] 5006.843/4958.511 line intensity ratio of 2.98 is obtained .
In order to check this new value using AGN spectra we present the measurements of the flux ratio of the [ OIII ] \lambda \lambda 4959 , 5007 emission lines for a sample of 62 AGN , obtained from the Sloan Digital Sky Survey ( SDSS ) Database and from published observations .
We select only high signal-to-noise ratio spectra for which the line shapes of the [ OIII ] \lambda \lambda 4959,5007 lines are the same .
We obtained an averaged flux ratio of 2.993 \pm 0.014 , which is in a good agreement with the theoretical one .