|
TEST CHART 2000 : HARDWARE REQUIREMENTS
|
|
|
Quick Links
|
|
Test Chart 2000 can be installed on virtually any PC running Windows 98 or later. By modern standards, the hardware requirements are minimal. The information below will help you select appropriate hardware but if you have any further questions, one of our engineers will be happy to advise.
|
|
CHOOSING A PC
|
|
Test Chart 2000 will run on virtually any PC running Windows 98 or later. You do not need a state of the art machine but you may find that the old machine that you have rescued from the loft may be a bit too slow when it comes to drawing the more complex displays. Also older machines may not be capable of generating high enough screen resolutions - we recommend a minimum of (1024x768).
If you are buying a new computer, the entry level specification is more than adequate for the task. Read the section on graphics cards below before ordering. Also have a look at some reviews in computer magazines to find the best value for money.
|
|
|
LAPTOP OR DESKTOP?
|
|
Laptops
For domiciliary work a laptop is ideal. Place the laptop on a suitable flat surface, measure the distance to the patient and enter this into Test Chart 2000. The program will then scale everything appropriately for this distance and you have your full battery of consulting room tests available. The IR remote control is very useful under these conditions as it allows you to control the program from up to 10 metres away avoiding having to walk to and fro to use the keyboard.
Some practitioners also use a laptop in the consulting room, either using the laptop display or plugging in a separate monitor.
To use the laptop display you obviously need to mount the laptop at a suitable position in the consulting room, either above the patient's head (for mirror viewing) or at the other end of the consulting room for direct viewing. In either case you will probably need to use the remote control to operate the program.
Alternatively, you can plug an external monitor into most laptops. This allows you to have the laptop in front of you and a second display for the patient to view. This can work well but make sure that the laptop can support the resolution of the second monitor, i.e. if the second monitor has a resolution of 1024 by 768, check that your laptop can support this resolution.
Laptops do have the big advantage that they take up less room so for a small consulting room this is a good solution.
Desktops
Desktop PCs are generally cheaper than laptops on a feature to feature basis. However they do take up a bit more room in the consulting room. One of the main advantages of a desktop is that they can support two monitors (when equipped with two graphics cards or a Dualhead graphics card). This means that one monitor can be dedicated for displaying the test chart while the other can be used for operating practice management software, imaging programs, word-processing or whatever. This is probably the ideal setup in the consulting room.
|
|
CHOOSING AN OPERATING SYSTEM
|
|
Test Chart 2000 will run under all versions of Windows from 98 onwards. However, it is worth noting that Windows NT does not support two independent monitors.
Test Chart 2000 is not suitable for use on an Apple Mac at present.
|
|
CHOOSING A GRAPHICS CARD
|
|
|
By modern standards, the demands of Test Chart 2000 in terms of graphical processing are minimal. The graphics card should be able to support the resolution of the flat panel display in True Colour (32 bit)
|
|
DUAL MONITOR SUPPORT
|
|
All versions of Windows after Windows 98 (but excluding NT) support the use of two independent monitors. This is particularly useful for Test Chart 2000 as one monitor can be used to display the test chart while the other can be used by the practitioner to run other software.
|
|
|
To drive two monitors you will need to either install two graphics cards into your PC or a “dualhead” card such as the Matrox G550. You will also need to set up Windows for dualhead support by selecting Display Properties from the Control Panel.
|
|
|
Many graphics cards can support two monitors, e.g. the Matrox G550.
|
|
CHOOSING A FLAT PANEL DISPLAY
|
|
|
|
|
|
Modern Flat Panel Displays (FPDs) are ideal for displaying Test Charts.
They are light (easy to wall mount), have excellent resolution and contrast (typically >250:1) and are flicker-free. They are also capable of producing adequate luminance (>200 cdm-2), are remarkably immune to ambient light, have good uniformity across the screen and are very stable over time.
The price of FPDs has plummeted over the past few years making computerised Test Charts a very cost-effective alternative to conventional charts and projectors.
|
|
Size: A 17'' flat panel display is generally adequate for displaying Test Charts. However, if you are using a long viewing distance (>6m) or see a lot of visually impaired patients it may be worth considering a larger display.
Resolution: The resolution of flat panel displays is mainly determined by their size. Most 15'' displays have a resolution of 1024 x 768 while 17’’ and 19’’ displays usually have a resolution of 1280 x1024.
Viewing Angle: Modern flat panel displays have very wide viewing angles (i.e. the luminance remains constant from a wide range of viewing angles). In the consulting room the display will be viewed from at least 3 metres so this is not a major consideration.
Screen luminance and contrast: Most flat panel displays are capable of producing a luminance of 150 cdm2 or more and contrasts in excess of 200:1. This complies with the European and British Standards and is perfectly adequate for displaying test charts.
Screen uniformity: Flat panel displays generally have very uniform luminance across the screen and are very stable over time - much better than the average projector chart!
IMPORTANT: If you want to mount the flat panel display directly on the wall (the neatest solution) check the following:
- It has VESA compliant fittings (screw holes in standard locations so that a standard wall mounting bracket can be used - available from us if required)
- It has a separate power supply - some models have the power supply built in to the base unit
|
|
POSITIONING THE DISPLAY
|
|
The display may be viewed directly or via a mirror (Test Chart 2000 will reverse all the optotypes).
Test Chart 2000 can be calibrated for any viewing distance (1 m to >10m). However, viewing distances of less than 3m are not recommended for a number of reasons:
- The Visual Acuity (VA) of uncorrected myopes may be overestimated.
- The endpoint of a refraction will be less well defined and some allowance for the viewing distance may be required.
- The small letters on the chart will be less well reproduced at very small sizes.
|
|
|
A study carried out by Professor Thomson suggested that measurements of VA and refractive error are more accurate for viewing distances of greater than 4m.
If a consulting room is less than 4m long, the display may be viewed via a mirror. Simply mount the monitor above the patient's head (as shown above) with a mirror at the other end of the room. Ensure the mirror is correctly positioned so that the display is seen in the centre of the mirror. Measure the distance from the patient’s eyes to the mirror and from the mirror to the chart and enter the total viewing distance into the program. Remember to select “Mirror Optotypes” from the program setup.
|
|
MOUNTING FLAT PANEL DISPLAYS
|
|
|
Flat panel displays are relatively light and most can be wall-mounted using a suitable bracket.
When purchasing a display, check that it has:
- a VESA compliant fittings (most do but check)
- a separate power supply (not incorporated into the base unit
A range of mounting brackets are available from Thomson Software Solutions
|
|
CONTROLLING THE TEST CHART - IR REMOTE
|
|
Considerable effort has gone into ensuring that Test Chart 2000 is easy to use. Most of the time, a single key press is all that is required to rotate around your favorite sequence of charts and displays.
The program can be controlled using the keyboard, the mouse or using the optional IR remote control.
The remote control system consists of an IR receiver that plugs into the USB port and a customised handset. All aspects of the program can be controlled using the remote control - you can even point at letters on the charts from the comfort of your stool!
More information
|
|
|
The remote control system therefore saves space (no keyboard or mouse required), gives rapid access to all the display options and provides complete freedom in the consulting room.
|
|
LET US WORRY ABOUT THE HARDWARE
|
|
|
If this all sounds a bit daunting, why not let us worry about the hardware.
We can supply you with a range of hardware with software pre-installed.
Our Integra range consists of a high-quality flat panel display with an integrated PC al in one elegant unit. Simply mount the unit on the wall and you are ready to go!
Alternatively, why not consider the Integra MINI. This is a mini PC which s supplied with the software pre-installed.
|
