Caroline Aherne and her brother Patrick were both diagnosed with a type of eye cancer as babies.
Aherne's sight was saved, but her brother had to have his right eye removed to prevent the cancer spreading.
Known as retinoblastoma, it is genetic and can lead to children losing both their eyes and at higher risk of developing further cancers in adulthood.
Aherne, who has been working with the trust on a campaign to highlight signs of the condition, said, "It is absolutely crucial that parents are aware of this horrible cancer."
More top news
The postal services company 'apologised for the inconvenience' after delivering the postcard, which was dated 1966.
Man who has barricaded himself in house for three days may have a stash of petrol and other explosives, police say.
Jessica Drake is the 11th woman to allege Donald Trump engaged in inappropriate sexual behaviour.