“It really doesn’t matter whether you’re talking about the oppressed or the oppressor — an oppressive society will dehumanize and degenerate everyone involved,” says Lorraine Hansberry in a trailer for Tracy Heather Strain’s new documentary “Sighted Eyes/Feeling Heart.” Best known as the playwright behind “A Raisin in the Sun,” Hansberry was also a feminist, lesbian, and civil rights activist. As the spot emphasizes, she “wasn’t just a mainstream liberal — Lorraine was a left-wing radical.”

“I was introduced to Lorraine Hansberry when I was 17 because my grandmother took my sister and me to see a performance at the Harrisburg Community Theater of ‘To Be Young, Gifted and Black,’ the play about Hansberry’s life,” Strain recalled in an interview with us. “It was quite a revelation to see and hear a young black woman who was really smart speaking about things that I had noticed, describing things that were similar to incidents that I’d experienced, and yearning to translate it all in a way that other people could understand. When and where does one hear and see stories that include the experiences of middle class black Americans?” she asked.

As one interviewee in the trailer puts it, Hansberry “was reaching into the essence of who we were, who we are, and where we came from.”

Strain’s previous directing credits include episodes of miniseries “Unnatural Causes” and “I’ll Make Me a World: A Century of African-American Arts,” and episodes of PBS’ “American Experience” and “Race: The Power of an Illusion.”

“Sighted Eyes/ Feeling Heart” is currently screening at the Toronto International Film Festival and will air on PBS’ “American Masters” in February. LaTanya Richardson Jackson (“Show Me A Hero”) narrates the doc and Anika Noni Rose (“Dreamgirls”) provides voiceover for Hansberry, who died in 1965. Both women earned Tony nods for their performances in the 2014 Broadway revival of “A Raisin in the Sun.”