People who are short-sighted can usually see close up very clearly but everything in the distance is blurred to a greater or lesser degree depending on the power of the lens they need to correct their myopia. The furthest distance at which they see clearly (in metres) is the reciprocal of their lens power - so someone who has -0.50D of myopia can see clearly up to 2 metres (1/0.50 = 2), whereas someone who is -10.00D can only see clearly up to 0.1m away (10cm, or 4 inches).

Myopia is easily corrected with glasses and there are a wide range of thinner and lighter lens options available in both high-index glass and plastic. Contact lenses are the best means of correcting myopia as they will usually give better vision than glasses unless the person has a high degree of astigmatism.

Even a tiny degree of myopia can drop a person's vision below legal driving standard so it is vitally important to have regular eye tests every 2 years.

The cause of myopia is either because the eyeball is too long, or the front of it (the cornea) is too curved (too powerful) which causes light entering the eye from a distance to be focused in front of the retina. Children often become myopic as they get older because the eye may grow too long. A child that sits too close to the TV, or is much more interested in near tasks such as reading should be examined by an optometrist. In the UK eye tests for children are free on the NHS.