I used Macbooks with no problems, including LED models, until they changed "something" around 2011. I do know some people more sensitive than me started having issues around 2008-2009 and some people who are very LED-sensitive or PWM-sensitive had issues even earlier. Heck, my grandmother had problems in the 1960's and 1970's with flickery fluorescent lights in her factory job and needed special glasses with a brown tint.
But I think the majority of us were good up through the iPhone 4/4s era, which also included Macbooks through 2009/2010. My personal trouble started when my formerly-ok Macbook (Core i5 Matte-finish UHD, 2010 model) went out for service and came back with a screen I could no longer use. Then lights began bothering me, many LED screens, etc.
The year 2011 was zero problem for me, it was 2012 that really kicked my ass.
But that's just me - others have different experiences.