The research, carried out to coincide with National Eye Health Week, found that 13 per cent of adults forego the check-ups because they believe they cannot afford them.
The survey of more than 2,000 people found that 90 per cent know about the benefits of having eye tests.
David Scott-Ralphs, chairman of National Eye Health Week, said: "This is a massive public health issue. Many people do understand the importance of a sight test, but there is great concern that they are still avoiding having one, often citing cost grounds.
"Many people qualify for a free NHS sight test and may also qualify for help with the cost of spectacles or contact lenses."
The average sight test costs about 20, a spokesman for National Eye Health Week said. National Eye Health Week begins today.