If you wish to purchase a magnifier to help with a sight disability or a low-vision need we strongly recommend that you consult a qualified optical practitioner or one of the organisations listed below. Under no circumstances should you construe any content on this web site to be professional medical advice. We accept no liability for any claim arising in connection with this.

Whatever your requirement, you will need to know where, when and why you will be using a magnifier. Here are just a few common uses:

We have magnifiers which can assist you with any of these tasks. In order to help you make the right choice the following information may be of interest:

• The strength of a magnifier is sometimes referred to as its ‘power’ and is usually expressed as a multiple with the x (*times) sign. For example, a 2x magnifier doubles the size of an image. Sometimes the power is expressed in dioptres. To work out the magnifying strength divide the number of dioptres by 4 and add 1.

• As a general rule the larger the lens the less powerful it is. Magnifiers with large lenses are fine for a wide all-round view of a subject and where low magnification is sufficient. Use magnifiers with smaller lenses when high power is required – on precision or inspection work for instance.

• To maximise your field of view, hold the magnifier as close to the eye as possible and bring the subject closer to the lens until it is in focus. The field of view will decrease with more powerful, but smaller lenses.

• Consider using different magnifiers for different tasks.

• Keep lenses protected to avoid scratching them. Try not to touch the lens surface with fingers as this will create grease smears which causes blurring.

• Clean dusty lenses with a soft, clean cloth to remove dust. Clean greasy lenses with warm soapy water (simple magnifiers only: never do this with illuminated or telescopic devices).

• Work in natural light where possible. You should not work in your own shadow or have to view anything against the light. Consider using adjustable lamps and special daylight bulbs to help control the quality and amount of light falling onto a task. If necessary take specialist advice on this to achieve a result you are happy with.

• Do not leave magnifiers where they might be exposed to the suns rays (e.g on window sills, outside) because this could cause a fire.

If you are visually impaired or suffer from a low vision disability you may be able to get a suitable magnifier free on loan through the Hospital Eye Service. Such arrangements vary from area to area: contact the RNIB Helpline (0845 7669999) or your local health authority or eye specialist to get more information. Even if you do have to buy a low vision aid you may have the opportunity to try one out at home first.

COMMON TERMS

• RNIB's Low Vision Service is based in the Eye Health Unit - tel. 020-7388 1266.

• The Partially Sighted Society, 62 Salusbury Road, London NW6 6NS - tel. 020-7372 1551

• There are many local societies for visually impaired people some of which provide low vision advice. For the address of your nearest society, please contact the RNIB at the above number.

• 'You and your sight: living with a sight problem' is a short guide by RNIB to sources of help. It is published by HMSO in large print, price £4.95 a copy and can be found in good bookshops. It is also available in tape and braille from RNIB.

• The 'In Touch Handbook' is a very detailed publication with useful information on all aspects of visual impairment and the services available. Contact your local library for a copy.

• The RNIB also publishes several handy booklets in their ‘See for yourself’ series. Call 0845 7023153 for details.

• Royal National Institute for the Blind (RNIB) - http://www.rnib.org.uk/wesupply/fctsheet/lvaids.htm
• CTP COIL: http://www.coil.co.uk/