Bierley's MonoMouse

As more visually impaired patients enquire about electronic magnifying devices, Jane Macnaughton describes a new and easily affordable addition to those available in the UK

IT IS SO refreshing when something new comes on the market for visually impaired users. After all, when it comes to making things appear larger, there are a limited number of ways in which it can be done. If magnification can be packaged in a simple-to-use, good quality product that appeals to a wide range of patients, there will certainly be a market.

When it comes to pricing, Bierley has firmly beaten the rest of the current market players. The MonoMouse is a good quality video magnifier retailing at £99 plus VAT - just a few pounds more than a good quality optical magnifier of similar magnification.

With approximately 70 per cent of visually impaired in the UK being over 75 years of age,¹ there is a need to produce an ergonomic device which is affordable and attractive to visually impaired users, including the elderly. The Department of Health has estimated that the total number of visually impaired is set to rise by 25 per cent in the next 20 years.² This will undoubtedly result in a greater demand for services for visually impaired people, which will include the provision of low vision aids.³

The advancements and improvements in quality and efficiency of components have widened the use of electronic magnification. All age groups are now regular computer users and as relative costs reduce and portability improves it is predicted that domestic use will become commonplace. In time the elderly will turn to electronic magnification as a principal method of magnification.

In a previous OPTICIAN article, Bill Harvey argued that the use of electronic magnification should now become a regular feature of low vision consultations within all age groups.⁴

The MonoMouse fits comfortably into the patient's hand and the one-touch blue button is highly visible

It is arguably fundamental for low vision practitioners to discuss and preferably demonstrate the advantages of electronic devices alongside the established optical approach to prescribing magnification during the consultation.

The concept of using a CCTV as a low vision aid has been a reality for some time.^5-7 Despite the advantages of an enhanced image and significantly more magnification than optical devices, the high cost of equipment and lack of portability has previously limited their use to the workplace or schoolroom, where funding may be applied for.

Over recent years more portable video magnifiers have become available, offering good quality images at a lower cost than the conventional CCTV systems. However, all are still in the region of several hundred pounds, which is still a limiting factor for a significant number of patients, especially the elderly.

The MonoMouse
The MonoMouse is a relatively new product, but its concept is probably not. Bierley has taken an optical mouse and have modified its use as a video magnifier for the visually impaired. I was surprised by its sheer simplicity and even more surprised to find that it is one of a kind. The use of a computer mouse, or at least something similar, may have been tried before, but the Bierley team are using recent advancements of CMOS technology, which results in an affordable device with low power consumption and excellent image quality.

Until fairly recently, video magnifiers have been using CCD (charge-coupled device) semiconductor technology to capture digital images in much the same way as our personal digital cameras or camcorders. One of the drivers behind the falling prices in digital cameras has been the introduction of CMOS (complimentary metal-oxide semiconductor) image sensors.

Bierley has taken an optical mouse and modified it as a video magnifier

CMOS sensors are much less expensive to manufacture than CCD sensors. Although CMOS sensors were traditionally more susceptible to noise, had lower quality, lower resolution and lower sensitivity, CMOS sensors are now improving to the point where they reach near parity with CCD. CMOS imagers offer more integration (more functions on the chip), lower power dissipation and smaller system size and are thus more suited to portable devices.

The MonoMouse is based on most recent cutting edge CMOS technology which, I assume, is one of the reasons why the image quality is so good and that the cost is low compared to other electronic aids. The same technology allows the MonoMouse to automatically calculate the brightness of the material that is being read and make 'instant' adjustments so that the screen image is always in perfect balance. This means that a user can move the MonoMouse from a bright white sheet of paper to a piece of regular newspaper and the MonoMouse will take care of the image quality automatically.

 
Simple to use
The MonoMouse expands the use of electronic magnification within the home environment. The MonoMouse is simply connected via the SCART socket point in the back of a television set and the image captured is displayed on screen. Most televisions in the UK, and throughout Europe, have been equipped with SCART connectors for the last 10 to 15 years and so the MonoMouse was designed to take advantage of a special SCART feature called auto-detect. When the patient is watching the television on any channel, it is possible to simply press the large blue on/off button on the MonoMouse and the television screen automatically switches to display the text that the viewer wishes to read. Once finished, the on/off button is pressed again and the television automatically reverts back to the channel that was originally being viewed.

MonoMouse is also available using the worldwide standard RCA connector for anyone who doesn't have SCART.

The mouse itself fits comfortably into the patient's hand and the simple one-touch blue button is highly visible. Patients have reported that the slightly larger than average size of the MonoMouse itself is easier to use than a standard-sized optical mouse, which makes it attractive to those who find handling an issue. The magnification levels produced are shown in Table 1.

One of the most useful aspects of the MonoMouse is its portability. Although it does need to be plugged into a mains socket, it still means that patients may take it on holiday, or to a relative's when visiting. Compared to optical devices of the same magnification, patients may retain a binocular view at a comfortable viewing distance from the TV screen, eliminating the problems of convergence and the uncomfortable reading posture that is often problematic with high-level optical magnification. With this advantage, sustained reading tasks may be possible, although success will ultimately rest with the patient's acuity reserve, as with all devices.

With optical magnification, the closer the patient is to the plus lens of the magnifier, the greater will be the field of view, and the greater the number of characters visible. By using a television screen to view the magnified image, the field of view is not influenced by the eye-monitor distance, unless the patient is very close to the monitor, when the reverse becomes true. Both the field of view and the magnification of the system will be largely dependent upon the screen size. Reducing the screen size will therefore result in a smaller field of view and less magnification.

Currently, the MonoMouse does not come with an image reversal function, common to other electronic systems. For many patients this facility is particularly useful, and for some a necessity. By reversing the contrast from black on white to white on black, there is a reduction in light scatter within the eye which will improve performance in those patients who have media opacities or who are photosensitive.

However, following the successful launch of the MonoMouse, I was pleased to hear that there will be a device incorporating an image reversal function. In addition, a ColourMouse will soon be available and also the MonoMouse USB which will benefit computer users.

Conclusion
What amazed me about the MonoMouse is that if is so simple in its design, why had it not been done already. Perhaps I am over-simplifying the technology, but from a patient's perspective, which is perhaps what we as low-vision practitioners are more interested in, the MonoMouse is offering good-quality magnification at a very low price. We will certainly be incorporating a demonstration of the product within our clinics at the University.

More information can be found on the Bierley website at: www.bierley.com

References
1 RNIB: Estimates and Registration Statistics for the UK 1995.
2 Low vision Services Consensus Group Recommendations for future service delivery in the United Kingdom, 1999.
3 Ryan B, McCloughlan L. Our better vision: what people need from low vision services in the UK London, RNIB,1999.
4 Harvey WJ. Electronic Low Vision Aids, a new image for the visually impaired. optician, 2004; April 23, No 5948 Vol 227.
5 Potts AM, Volk D and West, SS. A television reader as a subnormal vision aid, 1959.
6 Grenensky SM, Petersen HE, Moshin HL, Clewett, RW and Yoshimura RI. Advancements in closed circuit television systems for the partially sighted. Rand. Santa-Monica R-1040. HEW/RCA, 1972.
7 Grenensky SM. Some comments on a closed circuit TV system for the visually handicapped. Amer J Optometrist,1969; 46, 519-24.
8 www.dalsa.com/markets/ccd_vs_cmos.asp
www.dalsa.com

Jane Macnaughton is a visiting lecturer at City University, London and the proprietor of Clearview Training