Video-based and Computer-linked Devices

In the areas of high technology and closed circuit television (CCTV) assessments, the Centre for Sight Enhancement (CSE) has developed some novel protocols for individualized service delivery. Many service providers routinely demonstrate CCTV devices to their patients, but this simply demonstrates the device’s capacity to provide high levels of magnification for people with severe vision loss. Few clinicians systematically demonstrate the other co-adjustable enhancements that are unique to all of these devices, including zoom magnification, image polarity, image contrast, and selective chromaticity. Stable image localization, a large field of view and exceptional depth of focus are other unique generic attributes of these systems.

Mindful of these significant differentiations from optical “reading” devices, we routinely demonstrate CCTV systems to people with all levels of acuity impairments. In addition to appreciating the aforementioned generic features of these devices, many consumers are also sensitive to other more particularized and subtle features that may improve their comfort, speed, facility, and endurance while using a CCTV. These non-generic options can only be evaluated by comparing different types of CCTV systems. A basic in-line CCTV unit serves as a benchmark product.

Compared to this basic system, all others have additional features that will make them more or less useful for each individual consumer. These added features may include portability, monitor placement, monitor size, masking and isolation options, shared display options, underline features, color display, and ease of set-up, control and operation. Whether these added options are flaws or features depends on their demonstrated utility when the individual attempts the various activities that prompted her to consider a CCTV device in the first place. If the added features can’t be used for any reason, or if they don’t achieve the desired effect, they may simply add needless cost and complexity to the system.

These assessment protocols recognize the important distinction between verified utility and presumed utility. Someone who wants to read a newspaper or a book must use each device for this express purpose, rather than reading a test card with different print samples on it. Some systems may work very well with sample test materials, but fail miserably when used for reading the real material of interest. This process also allows consumers to see how each device functions for prolonged reading tasks, if this is how they intend to use the system. Similarly, if the person wishes to use the CCTV for reading foreign language material, household bills, or written correspondence, it is important to use real samples for evaluating each device. The consumer should be required to locate and use each control feature to allow him to compare any operating differences.

This hands-on approach is particularly important for evaluating hand-operated camera systems or other out of line systems, where some consumers may experience considerable difficulty with tracking and alignment. The bottom line is to provide consumers with an opportunity to use each system in the way that they expect to use it after they purchase it. Follow-up interviews and confidential patient surveys monitor the functional results of our prescribing protocols. We find abandonment rates to be consistently less than 5% per year, and fewer than 2% of our clients abdicate their initially selected devices in favour of other competing devices.