Short-sightedness and long-sightedness

Also called Myopia, Hypermetropia, Astigmatism, Refractive error

The commonest reason people cannot see clearly, and entirely correctable. Free eye tests exist for the groups most likely to miss out.

What it is

The eye not focusing light precisely on the retina. Short-sightedness blurs distance, long-sightedness makes close work harder and tiring, and astigmatism distorts at all distances because the eye's surface is shaped more like a rugby ball than a football.

It is not a disease, and glasses or contact lenses correct it completely.

Two things make it worth an entry.

**Childhood short-sightedness is increasing rapidly worldwide**, associated with less time outdoors and more close work. Time outdoors, at least two hours a day, genuinely reduces the risk of developing it, and treatments now exist that slow its progression in children, including specific spectacle lenses, contact lenses and low-dose atropine drops. High myopia in adulthood carries real risks of retinal detachment, glaucoma and macular problems, so slowing progression matters medically and not just cosmetically.

**Uncorrected refractive error is a hidden cause of apparent decline in older people and of difficulty in children.** A child struggling at school, or an older person becoming withdrawn, falling, or seeming confused, may simply need an eye test. See falls and dementia.

NHS sight tests are free for under-16s, over-60s, people with diabetes or glaucoma, and people on certain benefits, and many eligible people do not know.

Signs you might notice

Short-sightedness: blurred distance vision, screwing up the eyes to see, sitting close to the television or the board at school, headaches.

Long-sightedness: tired eyes, headaches after reading, difficulty with close work, and in children sometimes a squint.

Astigmatism: blurring or distortion at all distances, and headaches.

In children: sitting close, holding books close, squinting, head tilting, poor concentration on close work, or unexplained difficulty at school.

In older people: bumping into things, falls, difficulty reading, and withdrawal.

Urgent, and not refractive error: sudden change in vision; flashes, floaters or a curtain across vision; a painful red eye; double vision; or loss of part of the field of vision. See detached retina and uveitis.

How it can affect day-to-day life

An eye test is a health check, not just a shopping trip. It detects glaucoma, diabetic retinopathy, macular degeneration and sometimes signs of high blood pressure and brain tumours, in people with no symptoms.

Children should have vision screened at four to five, and any concern at any age is a reason for a test; children do not know their vision is abnormal because they have nothing to compare it with.

For children who need glasses, wearing them consistently matters, and school support makes the difference between glasses worn and glasses in a bag.

For older people in care settings, glasses are frequently lost, broken, or the wrong prescription from years ago, and nobody notices. Labelling glasses and arranging domiciliary eye tests, which are available free to those who cannot leave home unaccompanied, is genuinely under-used.

Two pairs, distance and reading, or varifocals, both have trade-offs; varifocals increase falls risk in some older people, and separate distance glasses for walking is often safer.

Supporting someone well

Have regular eye tests, usually every two years, and know whether you qualify for a free one.

Get children's vision screened at four to five, and tested at any concern.

Encourage at least two hours outdoors a day for children; it reduces short-sightedness.

Ask about myopia control options for a child whose short-sightedness is progressing.

Make sure glasses are worn, labelled and up to date, particularly in care settings.

Arrange a domiciliary eye test for anybody who cannot get to an optician.

Consider separate distance glasses rather than varifocals for older people who are falling.

Get any sudden visual change assessed the same day; that is never refractive error.

Where to get help

A high street optometrist for eye tests, including free NHS tests for eligible groups and home visits for those who cannot attend.

A GP practice or eye casualty for sudden visual change.

RNIB helpline: 0303 123 9999.

Fight for Sight for information on eye conditions.