Peter and Gillian Attenborough, from Newburgh in Fife, believe chemicals sprayed on crops close to their home could have caused their son Jonathan's condition.

But a similar claim has been rejected by a Florida court.

Mr Attenborough said the ruling was another disappointment in a series of ups and downs.

Jonathan, nine, was born healthy, but developed a condition known as microphthalmia.

His eyes started to develop normally, but then stopped - causing malformation.

His parents believe the condition was caused because Mrs Attenborough lived near fields in which crops were regularly sprayed with fungicides while she was pregnant.

They blame chemical giant DuPont, saying its products were in the fungicides.

'No problem'

Despite the ruling in Florida court against a similar case, Mr Attenborough said: "We are all determined to carry on and we remain relatively confident things will work out for us.

"I don't think there will be any problem proving that the chemicals caused defects. The difficulty will be in proving that it caused each particular defect in our cases.

"The scientific evidence has improved over the past couple of years, though, so that will help."

Encouragement

Mr Attenborough, chairman of the Micro and Anophthalmic Children's Society, said his was one of three families in Fife and Lothian and Borders who are pursuing a legal case against DuPont in US courts.

Four years ago, the families were given encouragement when an American boy was awarded $4.4m - about £2.7 million - in damages.

A Miami court accepted that Benlate, which contains two types of fungicide made by DuPont, was responsible for the child being born without eyes after his mother was exposed to the then common fungicide.

But a Florida Appeals Court overturned that verdict this week, saying that a British expert's research was not accepted by the scientific community.

Billion dollar settlements

Jim Ferarro, the American lawyer acting for the Scottish families, said they would appeal against that court's ruling.

If the appeal scheduled for 2 March succeeds, more than 20 other families from Scotland, England, Wales and New Zealand are expected to bring cases against the company.

Since 1991 DuPont has paid more than $1bn in settlements with American nursery growers and farmers who said Benlate ruined plants.