Oliver Johnson, 16, was diagnosed with Leber Hereditary Optical Neuropathy (LHON) after first experiencing blurred vision on a family holiday last summer.
At first it was just in one eye, but the second followed a few months later and his sight has deteriorated to such an extent that he has had to give up playing football, although he is still able to go to school.
His parents Richard and Sheena have set up a Just Giving appeal with a target of £30,000 to fund vital treatment for the very rare genetic condition.
Within weeks, more than £10,000 has been raised, thanks to donations and fundraising efforts such as a sponsored bike ride and cake sale by staff at the Veterinary Health Centre in Greenways, St Annes, where Sheena works as a vet.
"Thanks so much to everyone who has contributed so far,” said Sheena.
"We first noticed a problem when Oliver said his vision was blurred in his left eye while we were on holiday in Scotland last summer.
"We took him for an eye test, which showed up nothing untoward, but when the sight didn't improve, we arranged to see a consultant opthalmologist.
"Oliver had an MRI and a blood test and the consultant diagnosed this genetic condition which he said was so rare he had only encountered two previous case in 30 years.
"Oliver’s vision in his right eye became blurred around November and that has deteriorated too, so much so that he had had to give up playing football, which he has always loved.
"He’s still able to go to school, but he has his GCSEs coming up and we’re worried how he will go on with those.
"He’s on medication but the tablets he needs aren’t available on prescription in England, although they are is Wales and Scotland and elsewhere, so they have to be paid for. There is also treatment available in France.
"We have been told that the eyes should stabilise in time but there is no way of knowing how much the sight will have deteriorated before that happens or when it will happen.”
Blurring and clouding of vision are usually the first symptoms of LHON, beginning in one eye or simultaneously in both eyes; if vision loss starts in one eye, the other eye is usually affected within several weeks or months.
Over time, vision in both eyes worsens with a severe loss of sharpness and colour. The condition mainly affects central vision, which is needed for detailed tasks such as reading, driving, and recognising faces.
Oliver is a pupil at St Michael’s High School Chorley, played football for the under-16s at nearby Brinscall and lives with his parents and younger sister Francesca at Whittle-le-Woods, near Chorley.
Although he has had to give up football, he is still a keen runner and has two fund-raising mini-marathons planned for later this month.
Camilla Laing, a receptionist at the Veterinary Health Centre in St Annes, said: “We’re all really concerned for Oliver and want to do everything we can to help.”
Details of the appeal for Oliver are here