A final ruling will be made on the fate of a terminally ill baby boy whose parents want to take him to the US for treatment.
Ten-month old Charlie Gard has a rare genetic condition and brain damage.
Doctors said he would not benefit from the US trial and want to stop his life support treatment.
His parents began the European Court of Human Rights challenge after losing a Supreme Court appeal, exhausting all UK legal options.
European Court judges in Strasbourg are due to make a final decision later.
The court has told doctors at London’s Great Ormond Street Hospital to continue providing life-support treatment to Charlie until midnight on Tuesday, to give them time to examine papers filed by his parents’ lawyers.
Charlie has been in intensive care since October last year. He has mitochondrial depletion syndrome, a rare disorder that affects the genetic building blocks that give energy to cells.
His doctors said that Charlie can not see, hear, move, cry or swallow.
Specialists added that therapy proposed by a doctor in America is experimental and will not help.
A High Court judge in April ruled against a trip to America and in favour of Great Ormond Street doctors.
Mr Justice Francis concluded that life support treatment should end and said Charlie should be allowed to die with dignity.
Three Court of Appeal judges upheld that ruling in May and three Supreme Court justices on Thursday dismissed a further challenge by the couple.
On Monday parents Chris Gard and Connie Yates, from Bedfont, west London, shared a photo of Charlie with his eyes open.
Connie Yates posted the image on Facebook with the message “a picture speaks a thousand words”.
“As quoted from the judgement . . . ‘He is not consistently able to open his eyes enough to be able to see. Indeed, this leads to the difficulty that his brain is failing to learn to see’.”