Telefon
email
Facebook
Twitter
Pinterest
Instagram
Youtube

The Optical Knowledge Portal
Information – Education – Certification

Desktop video magnifiers

When vision is severely impaired...

...and can no longer be corrected adequately with prescription glasses or contact lenses, basic everyday skills are lost.
According to the German "Kuratorium Gutes Sehen”, an initiative for good vision, one in five people aged 70 and above have such poor vision that they can no longer manage with standard prescription glasses. With poor vision, opportunities to participate socially decrease and people’s sphere of action is greatly reduced. Advances in technology have, however, created new opportunities to make best use of the patients’ residual vision. Special optical and electronic magnifying devices can help enhance vision. Low vision solutions are now widely available for personal use and for use – for younger patients – in the workplace, which can be reconfigured as people’s needs necessitate.

Electronic magnifying devices

In addition to optical magnifiers, the number of electronic magnification systems available is increasing. The advantage of these devices is that visually impaired people can increase contrast while also adjusting the magnification to suit their individual requirements.

Electronic magnifying devices include:

Bildschirmlesegerät

Desktop video magnifiers provide quality of life for visually impaired people

Desktop video magnifiers offer high magnification levels of 60x and even more. With higher magnification, however, very little information fits on a screen. Often only a few words can be visualised on the screen, and long words cannot be displayed at all. Starting to use electronic vision enhancing systems is recommended from as soon as moderate magnification is needed. Judging from experience, it is ideal to start with magnification strengths between 6x and 12x.
As the visual acuity decreases further – often rather slowly – patients can increase magnification step by step to continue reading. In this way, they can gradually get used to the various difficulties that arise with higher magnification levels – usually with great success!

Advantages of desktop video magnifiers:

The best known electronic low vision aids and the ones that are most often used are desktop video magnifiers. They use a camera in a fixed position to enlarge the information e.g. in a newspaper article. The level of magnification can be individually adjusted as required or desired. The newspaper is placed under the camera on a moveable XY reading table, where it is instantly filmed and displayed on a monitor in larger type. The hard copy must be moved below the camera while reading. Camera, monitor and XY reading table often form a single compact unit. The key feature of desktop video magnifiers is their ability to enhance contrast, which can only be achieved with the help of electronic circuits and never by optical components alone.

Kontrasteinstellungen bei Bildschirmlesegeräten

In addition to high magnification levels, multiple contrast settings are another major plus of desktop video magnifiers.

Desktop video magnifiers are particularly useful for patients with reduced contrast vision and patients requiring high magnification. Corrective spectacles adjusted to the eye-screen distance are important to facilitate reading – not only after cataract surgery.

Application areas of desktop video magnifiers

Desktop video magnifiers capture texts and images with a camera and directly enlarge them on a monitor or screen. Patients can variably adjust the size of the screen image thanks to the wide magnification range. Contrast, brightness and the colour settings of text and background can also be changed to suit individual preferences; this is not possible with optical magnifiers.

Anforderungen an Bildschirmlesegeräten

Desktop video magnifiers are useful aids for different tasks (e.g. reading, writing or viewing photos).

Desktop video magnifiers are ideal for reading longer texts in newspapers, magazines or books as well as for writing and for filling in forms. Desktop video magnifiers are usually placed on a table for stability. For reading, the text is placed on the XY reading table, which is part of the device, and moved below the camera. A braking system integrated in the table helps the patient to better control the XY motion, providing additional security when reading or writing. Most users master the use of this device relatively quickly. As with other visual aids, appropriate training is helpful. Experienced users work with a desktop video magnifier at a pace that is dizzying even for people with good vision.
An autofocus camera provides crystal clear, sharp images. The image size can be variably enlarged from approx. 1.9x to more than 70x. Whereas a small print size provides a better overview, the magnification is usually increased when it comes to reading or seeing fine details. Here, too, the most important thing to note is that selecting higher magnification will result in less information being displayed. High magnification results in only a few letters being visible on the screen and is thus of little use for reading.

Nutzungsbeispiel eines Bildschirmlesegerätes

Standard monitor sizes vary between 20-inch and 24-inch. Some models offer additional features such as reading lines or reading masks that provide orientation on the reading material.
Desktop video magnifiers require mains power and, due to their size, they are usually not suitable for mobile use. Special attention should be given to ergonomic design and ease of use when selecting a device.

 Textmaskenbeispiel einer Bildschirmlesegerätes
Reading mask

 The monitor can be easily pivoted and adjusted for ergonomic comfort.

Lespositionen eines Bildschirmlesegerätes

Ergonomic adjustment is essential for a natural reading posture.

The range of desktop video magnifiers is continuously expanding. They are particularly useful for patients with severe sight impairment, enabling them to maintain their reading ability.
Starting to use electronic vision enhancing systems is recommended from as soon as moderate magnification is needed. Patients can then gradually increase magnification as required and can get used to the various difficulties that arise with higher magnification levels – usually with great success!
The benefits of desktop video magnifiers and traditional optical and non-optical low vision aids must be carefully compared to find the device that really makes a difference to the life of a visually impaired person. Optimising lighting conditions or fitting patients with illuminated magnifiers, high addition spectacles or telescopic systems may sometimes be the better choice for an individual patient.

For more information on video magnifiers click here.

Nutzungsbeispiel eines Bildschirmlesegerätes

 

 

Courtesy of
A. SCHWEIZER GmbH

Desktop video magnifiers - electronic magnification!1
Desktop video magnifiers - electronic magnification!2
Courtesy of

A. SCHWEIZER GmbH