Half of people in Ireland have not had an eye test in the past two years - the recommended maximum interval between eye tests, according to new research.

The survey also reveals that one in five have never had a sight test at all, rising to over 36% of those under the age of 35.

The research, in advance of a Healthy Eyes Awareness Week, found that the vast majority of those who have never had a sight test think they have 20/20 vision, even though they have no way of knowing whether they do or not.

It also reveals that 25% of smartphone/tablet users under the age of 50 report have reported eye strain.

The survey, based on a population sample of 1,000 people, has been published to launch the second national Healthy Eyes campaign which runs from June 16 - 22. Optician groups said the survey demonstrates that many people are neglecting their eye health.

Healthy Eyes is being coordinated by the Federation of Dispensing Opticians (FODO) Ireland, the Association of Optometrists Ireland (AOI) and the Irish Association of Dispensing Opticians (IADO) to remind people that even if they think their eyesight is good, the only way to know for sure is to get your eyes tested regularly.

FODO Ireland Head of Policy, Ann Blackmore, said research shows that sight is the sense people fear losing the most and yet most don't consider an eye test to be a core part of their health routine. An eye test is a vital health check which can detect a range of health conditions for which you may be experiencing no symptoms and where early detection can prevent sight loss."

By 2020, the number of people living with sight loss in Ireland is estimated to increase to 271,996. Given the growing incidence in key underlying causes of sight loss such as obesity and diabetes, this could represent an underestimate if Ireland does not take a comprehensive approach to early detection and treatment.

IADO President Ruth Drennan said: "The survey results are a worrying reminder of the lack of awareness of eye health issues in Ireland. The Healthy Eyes campaign message is a simple one - everyone needs a regular eye test and we encourage anyone who has never had one to do so this week."

It is estimated that more than 50% of sight loss is almost entirely preventable. Research also indicates that up to 75% of sight loss in older people can be avoided. These conditions can only be prevented if they are detected early and the key to that is regular eye tests.

There are already over 220,000 people living with sight loss in Ireland - and this number is projected to increase substantially as the population ages. The Government estimates that the number of people aged 65 years and older in Ireland will almost double over the period 2006 to 2026, with Irish and international data showing a marked increase in the frequency of sight loss with advancing age.

The Irish Government committed to the objectives of Vision 2020 almost ten years ago. This represents a global collaborative initiative led by the World Health Organisation (WHO) with the overarching objective to eliminate avoidable sight loss by 2020.