Challenges in behavioral optogenetics in large brains demand development of a chronically implantable platform for light delivery. We have developed Opto-Array, a chronically implantable array of LEDs for high-throughput optogenetic perturbation in non-human primates. We tested the Opto-Array in the primary visual cortex of a macaque monkey, and demonstrated that optogenetic cortical silencing by the Opto-Array results in reliable retinotopic visual deficits on a luminance discrimination task.