I've had melasma for 3 years and no matter what products I use it doesn't seem to treat it. Any suggestions?

I've been using Beverly Hills MD dark spot corrector and ISIS pharma unitone 4 white advanced for hyperpingmentation. Although it has helped with light acne scars, the noticeable dark spots seem to not fade away. I've done laser skin surgery and that hasn't helped at all. I need suggestions. Thanks!