A Canadian man who was beaten so badly by an off-duty police officer and his brother that he lost his eye, said he had “no chance to fight back” in the violent encounter that left him fearful he would go blind.

Dafonte Miller’s testimony in an Ontario court on Wednesday marked the first time he had spoken publicly about the 2016 incident.

Brothers Michael and Christian Theriault face charges of aggravated assault in the beating of Miller, on 28 December 2016. The brothers claim they acted in self-defence. The brothers have also been charged with obstructing justice.

The case of two white men allegedly assaulting a black teen, has also laid bare the disproportionate harm the black community faces at the hands of police. According to the Ontario Human Rights commission, black residents are overrepresented in fatal shootings and use of force.

In a packed courtroom in Oshawa, Ontario, Miller told the court he and two friends were walking together evening of 28 December, when they were stopped by two men in a driveway.

Miller, who was 19 at the time, described the initial encounter as “casual” until Christian Theriault asked the group what were doing in the neighbourhood. Despite being off-duty at the time, Michael Theriault told the three friends he was a police officer, and said he could ask them whatever he wanted, Miller told the court.

The boys began to walk away, but soon noticed they were being chased, said Miller, who said he was put in a headlock, before he was punched and then beaten with a meter-long metal pole.

“I remember just laying there … getting beat for a little while,” he said. “I wasn’t feeling it no more but I was seeing it.”

Miller was eventually able to escape and call police. Two neighbours also phoned emergency services.

Miller, who was 19 at the time, lost his left eye, which he described as “pretty much burst” after the attack and would bleed as he slept. He suffered other injuries, including a fractured wrist and broken bones in his face.

The brothers told the court earlier this week they were in their garage when they heard someone breaking into a truck. After encountering Miller and claiming he had a weapon, the two restrained him in self-defence.

Miller’s friends have provided conflicting testimony from that night: one says the group was searching cars for money, another denies breaking into vehicles. Crown lawyers say the Theriault brothers falsely claim they acted in self-defence and that Miller had a weapon.