A school girl who went to hospital suffering from headaches was horrified to be told she had a brain tumour the size of an orange.Doctors discovered the benign tumour inside Holly Dougill-Brooks's brain after they did an emergency MRI scan when they realised she had lost sight in her left eye in a matter of months.Holly, eight, had visited the opticians with her mother Melanie Dougill in August 2010 after suffering from a throbbing head.She was told her sight was fine but was referred to Northampton General Hospital as a precaution.When she had her appointment in July this year doctors said she had gone blind in her left eye and a subsequent scan revealed an orange-sized tumour.Holly was diagnosed with craniopharyngioma three months ago, a slow-growing tumour which is normally impossible to remove without causing serious damage.Following an operation to shrink the tumour by about 50 per cent, Holly will now travel to Jacksonville in Florida for a revolutionary new treatment called proton beam therapy, which it is hoped will cure it completely.However, she will be blind in her left eye for the rest of her life.The treatment, which is only available in the USA, France and Switzerland, is similar to radiotherapy but does not damage the surrounding tissue, and reduces the risk of secondary tumours in later life.Miss Dougill from East Hunsbury, Northampton, said: 'Holly deals with everything remarkably bravely. She is the most resilient child I've ever come across. She's happy, cheerful and takes it all completely in her stride.'It's so hard to describe how we felt. It was absolute devastation. I don't think I'll ever forget that moment when they sat us down and said: 'Holly has a brain tumour'. But you learn to deal with it day by day.'Talking about Holly prior to the diagnosis, she added: 'She had been having headaches and originally they thought it was to do with her eyes, but the optician said her sight was fine.'We were referred to the ophthalmic department at Northampton General Hospital (NGH) and they discovered she was blind in her left eye.'She had an emergency MRI on the Monday, and on the Wednesday we were called back and informed she had a brain tumour and was being referred to Nottingham for a biopsy and further investigation.'The NHS is paying for Holly and Miss Dougill to go to America. Miss Dougill's employer, the Continuum Group, is raising money to help Miss Dougill's partner Nathan and Holly's dad Alan to visit her during her treatment.Miss Dougill said: 'It's fantastic. I can't thank them enough. They have really gone above and beyond what we expected anyone to do for us.'