Test Chart of the future?
Dr David Thomson, a senior lecturer in Optometry and Visual Science at City University, London, has developed a computer program that could revolutionise vision testing in optometric and ophthalmological practice. The program, known as Test Chart 2000, takes advantage of recent developments in computer and display technology to provide a powerful, versatile and cost-effective alternative to conventional test charts and projector systems.
		The program can be run on a standard PC using either a conventional CRT monitor or a Flat Panel Display (FPD). Modern FPDs are particularly well suited to the purpose, being easy to wall-mount and capable of displaying high contrast, high luminance and flicker-free images. Loaded on a laptop, the program is also ideal for domiciliary work.
Test Chart 2000 provides the clinician with an extensive range of tools for vision testing including LogMAR charts, Snellen charts, single letter charts, duochrome tests, a fan and block test, cross-cylinder targets, a fixation disparity test, number plate tests, phoria tests and a contrast sensitivity test. The program also includes a library of over 100 images for use as fixation targets including a range of dynamic cartoons to maintain the interest of children.
A variety of optotypes are provided including letters, Landolt Cs, Tumbling Es, Kay pictures and foreign characters. The contrast of all the letter charts can be varied in approximately 750 steps allowing low contrast acuity to be assessed. The test stimuli can be viewed directly or reversed for viewing in a mirror and letter sizes are automatically scaled for any viewing distance between 3 and 10 metres. An on-going programme of software development will ensure that users are kept up to date as new tests are developed.
	The program has been tested extensively at City University and the Institute of Optometry. It has also been subjected to rigorous beta testing by 30 practising optometrists to ensure that the interface is optimised for use in practice. The program can be controlled by the keyboard, mouse or an infra-red remote control unit. Voice activated control is also under development.
The program was launched in April 2000 and is currently marketed by City University and Institute of Optometry Marketing. Over 200 practices and clinics already use the program and interest and demand at home and overseas is growing rapidly. Computer-based test charts are likely to become the standard tool for assessing vision in the consulting room in the near future. Test Chart 2000 is the first product to fully exploit these new developments in display technology and is likely to make a major and lasting impact on optometric practice.