The 28-year-old remains partially sighted in his left eye after a traumatic few days kick-started by the accident at the club's East Mains training base on Friday.
Stack was caught in the face by a combination of the ball and team-mate Abdessalam Benjelloun and immediately knew he was in serious discomfort as blood came from the eye.
The former Arsenal keeper was rushed to the Princess Alexandra Eye Pavilion in Edinburgh where specialists eased his initial fears by stating his retina was still attached.
But with bleeding inside the eye, a small clot on the pupil and inflammation, Stack has endured a difficult few days and is still waiting for his eyesight to fully return. Hopeful of avoiding an operation, he explained: "I'm still partially sighted, blurred vision really. I still haven't got my sight back.
"It was just a freak accident in training. I tried to make a block to save at Benji's feet and I think it was a combination of his foot and the ball. But it all happened so quickly. Just immediately I felt pain in general really, there was obviously a bit of swelling and blood coming from the eye.
"Myself and our physio rushed to the eye clinic just to make sure it didn't have to be taken care of immediately. We sat down with the specialist and went over a lot of routine checks. was reassured the retina was still attached and it was just a case of maybe 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, because they don't want my blood level raised."
With the SPL season finishing on 9 May, Stack is unlikely to be able to aid Hibs' quest for fourth place in the last three games of the campaign.
Contracted at Easter Road until 2011, he added: "I've just been resting at home.
It's hard to a put a timescale on it, but the way things are looking I've got a race to get back fit this season."
Stack's injury resulted in a recall for Graeme Smith for Sunday's SPL clash with Rangers, as Walter Smith's men claimed the title with a 1-0 success.
Considering Hughes also has fellow goalkeeper Mark Brown (wrist) out for the season and Yves Makalambay coming to terms with the death of his father, Hibs do not have their problems to seek in nets.
Stack, himself reduced to 22 appearances in his first season at Hibernian, added: "It's been unfortunate for me this season. The first couple of games I missed with my hamstring, then I had a bulging disc in my back that kept me out longer than expected.
"I've been hit in the face countless times by footballs and been kicked in the head countless times over the years. I'm not one to shy away from a challenge if need be, but unfortunately this time I've come off slightly worse. It's just the nature of the game and the nature of me really, if the ball is there to be won I'll go for it. Being a goalkeeper, sometimes you have got to do that."
Meanwhile, Hearts goalkeeper Marian Kello has been told he will not require an operation on his broken wrist.
The Slovakian has already been ruled out for the season and has not featured for Hearts since a 2-0 win over Hamilton Academical over a month ago.
The club feared he would require surgery after picking up the injury in training but, after having the cast removed on Friday, the 27-year-old will not go under the knife after all.
The news was welcomed by Tynecastle manager Jim Jefferies, who told Hearts News: "Marian will not have to have an operation.
"He had the cast taken off on Friday and the doctors have had a look at him again. He will need two to three weeks strengthening so that rules him out of playing again this season but it's good news that he will not have to have surgery.
"He can now concentrate on building his wrist up and making sure he is 100 per cent fit."
Hearts are also without Janos Balogh for their remaining games this term but Jefferies has been more than happy with the efforts of Jamie MacDonald, who has taken over between the sticks.
"I have no complaints about Jamie," he added. "He has come in and done a good job for the team and his performances have shown that this is an area where we are quite strong."