The absence of red eye in a photograph in one pupil could also point towards an aggressive cancer and information about the disease will be published (Thinkstock)
New parents are to be warned how to spot the signs of eye cancer in children.
Parents will be taught that the appearance of a whitish light on the eye, a squint, a sore or swollen eye or a deterioration in vision could be signs of life-threatening retinoblastoma.
The absence of red eye in a photograph in one pupil could also point towards the aggressive cancer.
Information about the disease will be published in the personal child health record, also known as the red book, given to every parent upon the birth of their child.
The move could save the sight of many children, the Childhood Eye Cancer Trust (CHECT) said.
Most children with the rare eye cancer lose an eye, and occasionally both, which could be prevented with earlier diagnosis.
CHECT chief executive Joy Felgate said: "Early diagnosis is essential to offer the child the best chance of saving their sight and their eyes. Parents need this information to enable them to act immediately if they notice the symptoms in their child's eyes.
"We are delighted the importance of this information for parents has been recognised and our recommended changes have been approved."
Mother-of-four Katy Bishop, whose two-year-old son Owen was diagnosed with the aggressive cancer, welcomed the news.
From Petersfield in Hampshire, Ms Bishop said: "If we'd have known that a glow in his eyes in a photograph could be something to be concerned about we would definitely have pushed for Owen to have been seen sooner.
"I am so relieved that future parents will have this information to hand. It will make a real difference to children diagnosed with retinoblastoma in the future."
The 32-year-old's son was diagnosed with cancerous tumours in both of his eyes when he was 11 months old.
Ms Bishop said: "I was devastated to find out he had cancer, and probably had since birth, and I was happily putting glasses on him, worry-free while the cancer robbed him of his vision.
"If there had been one paragraph explaining white glow in eyes could be a danger signal, I would have known months earlier what was wrong and queried the eye doctor when she told me not to worry.
"Because of the lack of information, I had no clue. I read my red book, front to back while sitting in health visitors clinics waiting for our turn.
"An earlier diagnosis really is crucial to lessen the trauma some children endure through treatment, so I welcome this action to include the warning signs in the red book. I can't wait to see how better awareness affects diagnosis pathway because it's currently very poor for most and it's time it changed. Vision is precious."
Ms Bishop's MP, Damian Hinds, Mumsnet, Vision Express and CHECT joined forces to campaign for the information to be included in the red book.
Retinoblastoma is a childhood cancer generally affecting retina of children from birth to six years old. Between 40 and 50 children are diagnosed with the disease each year.