The amount of time children spend on screens at school could be harming their "physical and developmental health", more than 150 clinicians have warned in an open letter to ministers.

GPs, paediatricians and other specialists wrote to Education Secretary Lucy Powell and Health Secretary Yvette Cooper, saying tablets and laptops are being used in classrooms in England without a full understanding of their long-term effects, including on eye health.

The clinicians said they are prescribing glasses, hearing aids and speech therapy to children "for a problem that is unintentionally being made worse in our schools".

'Wake up to this now'

The letter said nearly one million children are using screens in most lessons. Many now spend longer on screens in the classroom than is recommended for an entire 24-hour period, it claimed.

"As a country, we need to wake up to this now, and start rolling back screen use in schools before the damage compounds further," the clinicians wrote.

They pointed to an analysis of 276 studies covering 5.4 million participants worldwide, which they said found short-sightedness among children and adolescents had risen from about 24% in 1990 to almost 36% by 2023. Myopia is associated with an increased risk of eye problems later in life.

The letter acknowledged that "some of this evidence is still surfacing", but said "the direction of travel is consistent across multiple, independent, and in some cases very large, bodies of research".

It also warned that children with special educational needs are "disproportionately" directed towards screen-based learning.

No chance to opt out

One of the signatories, Dr Becky Foljambe, an NHS GP and founder of Health Professionals for Safer Screens, told BBC Radio 4's Today programme that parents had not been given the chance to opt out of "excessive" screen use in schools.

She warned that children risked "just not thriving" in education, and said an "explosion" in short-sightedness "cannot be put down to genetics alone".

Foljambe described it as a "lazy argument" to say screens were needed to prepare children for a digital world. "They also need their sleep, their eyesight, they need rest, they need ability to critically think and appraise," she said.

School leaders respond

Pepe Di'Iasio, general secretary of the Association of School and College Leaders, said education technology can give schools "very effective learning tools".

But he said technology was only part of an overall learning strategy that also includes classroom discussion and interaction, and that the school day includes "plenty of non-screen time such as PE, sport, and break times with classmates".

He said school leaders would welcome the development of practical, evidence-based guidance.

Government consultation

The government said it was consulting on screen time guidance for children aged five to 18, but stressed that technology could be a powerful learning tool if used properly.

The debate comes as many schools have moved to ban mobile phones during the school day, and as some countries, including Sweden, have reversed earlier pushes towards digital learning and returned to printed textbooks and handwriting.

A wider reckoning

Concern about children's screen use has grown sharply in recent years, fuelled by research on social media, sleep and attention. Campaigners argue that schools should be a place where children spend less time looking at screens, not more.

Supporters of educational technology counter that well-designed digital tools can personalise learning, help pupils with additional needs and prepare young people for the jobs of the future.

For parents, the letter raises a practical question: how much of their child's school day is spent in front of a screen, and whether anyone is keeping count.