The biggest rise is in children under the age of five and one in 20 severely premature babies in the UK are likely to be born blind.The charity Blind Children UK said that around four children lose their sight each day in the UK.Forty-three per cent of parents report that delays in diagnosis affected their child's development.Research by Blind Children UK, formerly National Blind Children's Society (NBCS), has revealed that as more premature babies are surviving than ever before, more are likely to be sight impaired at birth.The charity for children and young people with sight loss, has released the findings as part of a campaign to help raise awareness of the challenges faced by children with vision impairments and their families.Research has revealed that across the UK the number of children being registered blind or partially sighted has increased by 9% since 2006.The biggest rise has been seen among those under the age of five where a 12% rise was reported.It is estimated that the number of babies being born with sight difficulties as a result of being premature has risen by 22% over the past decade to more than 1,800.The earlier children are born, the greater the risk of vision impairment, the research has revealed.A quarter of the parents surveyed by Blind Children UK said that they had to wait longer than a year to have their child diagnosed with a vision impairment.Almost half (43%) of these felt that this delay had a 'negative' or 'strongly negative' effect on their child's development as it meant that they did not get the support needed from their local authority or school.Richard Leaman, CEO Blind Children UK, said: "Every day a child with sight loss goes without support, it dramatically affects their development."As much as 80% of a sighted child's learning takes place using vision. Without this, it's challenging for a young boy or girl to develop fully and make sense of the world around them."We help children and their families tackle all the challenges of sight loss, so that they can enjoy their childhood and fully realise their potential as adults."Blind Children UK's research also revealed that blind and partially sighted children are being prevented from enjoying and accessing basic education and recreational experiences.Some 40% of parents said that their child had had difficulty accessing events or playgrounds in their local area.There were also instances of children being rejected from schools and nurseries as well as swimming lessons because of their vision impairments.