Low Vision

Unfortunately some people develop a degree of sight loss beyond what would be expected with normal age related changes. Low vision is a term to denote a level of vision that is poorer than normal and that cannot be fully corrected with conventional spectacles.

The degree of visual difficulty that a person may experience cannot be predicted simply on the basis of how far down the standard letter chart they are able to read. Other factors include loss of side vision, glare sensitivity and reduced colour perception. The most common reasons for significant visual loss are macular degeneration, glaucoma and diabetic retinopathy.

It is rare today for someone to lose their vision completely. Even in advanced eye disease, there is often a degree of residual vision which can be utilised and developed using low vision aids.

Some of the conditions that cause low vision can be treated if diagnosed early so therefore it is important to visit your optometrist if you are worried about your eyesight.

Here are some examples of the most commonly prescribed low vision aids:

Hand Held and Stand Magnifiers
Available in a wide variety of powers and often equipped with an internal light source. An important point to remember is that as the magnification increases, the size of the magnifier lens reduces.

Bright Field Magnifier
Low magnification but very easy to use - not suitable for people with very poor sight

Eschenbach Stand Magnifier
Available with a wide range of powers and has internal illumination. Suitable for several levels of low vision. The magnifier is designed to be placed flat against the page
Coil Illuminated Pocket Magnifier
A more portable magnifier also available in a wide range of powers. Can be useful for simple tasks such as reading menus or shopping.
Scribolux
With the ability to write underneath, this magnifier is ideal for crosswords or writing letters. An internal light source provides excellent illumination and magnifies 2.8 times
Hand Held or Spectacle Mounted Telescopes
Minature telescopes used for viewing longer distances such as across the room to watch TV or approaching bus numbers or destination boards. Some styles are suitable for carrying in a pocket
Video Magnifier
This is an electronic magnifier which operates by placing printed material under a mini camera and the magnified image is displayed onto a screen. Although available in portable versions, the most common variety of video magnifier plugs into a conventional TV. The device is similar to a computer mouse and this is scanned across the page as the magnified test is read off the television screen. Approximately 24 times magnification can be achieved with a 20 inch television screen.
Light and glare control
Spectacle lens filters which reduce the transmission of shorter wavelengths of light can often benefit patients with low vision. These yellow and amber filters reduce light scatter which in turn can reduce glare outdoors. Samples of these filters are available in the practice.

The use and success of a low visual aid is dependant on many factors:
- The type and degree of visual loss
- Patients light and glare requirements
- The ability to handle and operate the aid
All of our optometrists have considerable experience with low vision assessments both within the Hospital Eye Service and in private practice.

The majority of patients requiring low vision aids are referred to us by their consultant eye specialist and in these instances most aids can be supplied on extended loan through the NHS. Exceptions to this policy would be patients requesting multiple aids and some of the new portable electronic devices - these would be funded privately.

Some useful Websites

Low Vision Aids: www.associatedoptical.com
Royal National Institute for the Blind: www.rnib.org.uk
Macular Disease Society: www.maculardisease.org.uk
International Glaucoma Association: www.iga.org.uk
Diabetes UK: www.diabetes.org.uk