A report by the Education Endowment Foundation (EEF) found an estimated 13 per cent of UK children may have undiagnosed common sight problems that undermine their literacy and education.
These conditions include short-sightedness, squints and amblyopia, also known as lazy eye, all of which can limit children's ability to distinguish letters or follow the actions of teachers.
The report also warns that children from poorer families are less likely to have their sight conditions treated following diagnosis.
The EEF's Preparing for Literacy report recommends that since the NHS does not have a national screening programme, early years services should be vigilant for potential eye conditions and encourage parents to access eye tests for children.
Childcare settings should also make sure that once a condition has been identified that children use their glasses or other treatments.
"Good literacy skills are fundamental - not just for academic success at school, but for fulfilling careers and rewarding lives," said Sir Kevan Collins, the EEF's chief executive.
"Yet more than one in ten children are estimated to have an undiagnosed sight condition that could affect their ability to read and write well.
"Making sure all young children with possible eyesight problems are identified, and those that are given glasses or other treatments use them is cheap way of removing this unnecessary barrier to learning. It should be a no-brainer."
The EEF's report also calls for early years settings to take a number of additional steps to boost literacy skills among children. These include using a variety of approaches to introduce children to new words such as shared reading and storytelling.
Early years professionals were also advised to talk with, not just to, the children in their care and provide targeted literacy support to children who start to fall behind catch up fast.
The report added that settings should make sure parents know how to help children develop their literacy and numeracy skills at home and help children learn to manage their own behaviour so that they can engage better in learning.
