The Hibs keeper's season is over as he struggles to see since being caught in the face by a combination of the ball and team-mate Abdesallam Benjelloun on Friday.
Stack, 28, was immediately rushed to hospital with blood pouring from his eye.
Specialists eased his initial fears by stating his retina was still attached, with an operation proving unnecessary. But with bleeding inside the eye, a small clot on the pupil and inflammation, Stack is still waiting for his eyesight to fully return.
The former Arsenal star said: "I still haven't got my sight back, I'm partially sighted, blurred vision really.
"I've got bleeding inside the left eye, a small blood clot on the pupil and my retina is bruised. There is basically a lot of trauma to the eye.
"It was just a freak accident in training. I tried to make a block to save at Benji's feet and immediately I felt pain and there was blood coming from my eye.
"Myself and our physio rushed to the eye clinic to make sure it didn't have to be treated immediately. We sat down with the specialist and I was reassured the retina was still attached and it was just a case of letting it settle down.
"My vision should start to come back, I was told between a week to two weeks.
"But I've been told I can't do any activity at all. They don't want my blood level raised as it could be dangerous with the blood clot there.
"So I've just been resting at home and have been back to the clinic and will be going again on Friday just to make sure there is progression and it's not deteriorating.
"It has improved but it's hard to a put a timescale on getting back. The way things are looking I've got a race to get back fit this season."