Rule of thumb is roughly arms length as you say.

But the main thing is that the user can read the screen clearly from the position they are sitting in. If they are too far away they may have a tendency to lean forward, thus potentially, negatively affecting their posture.

Theres so many things to take into account I would be suprised if any DSE user was 100% on the line with the guidance. Just remember there is always some individuality with these kinds of assessments.

Hi Jodie,
Thank you for that, I understand there must be some flexibility, and also that whatever recommendations you make most people will have a preferred way of working, that works for them and I respect that. However, I am the one carrying out the H&S DSE Risk Assessments, I am new to this and I have been using the HSE standard picture of a correctly set up user sitting at their desk. In this picture, the user is quite close to the screen and the surface of the screen is at approximately arms' length - and this is the distance that I am recommending to the users at my workplace. I have done around 12 or so assessments so far (only 65 to go), and someone (my boss) has challenged me on the 'arms' length' recommendation, and asked me to show where this comes from. He does not agree with it and likes to have his screen far back on the desk.
This why I am looking for some hard and fast information.
Many thanks

I agree with the others, I doubt you will find an optimum distance. However those of us that need glasses to see close up, have it a similar distance to the focal length of our glasses. I know when I was at the optician they asked where I hold a book etc to read and it was just a little shorter than "arms length" and so that is what my glasses were set at. I would not want two different pairs one for screen and one to read what is on my desk etc.

If he can see it without straining his eyes then all good.

Regards
Chris

Its regarding viewing angles, "at arms length" you can see the whole of the screen without having to move your head

I think it is important that we do not lose sight of the fact that we are all different. What may be right for one or most may not be right for another.

I am very short sighted and with a large difference between distance and near vision. I have worn varifocal spectacles for many years. Mine have a wide transition section between distance and near focal lengths.

When I attended a seminar on the DSE regulations the demonstrator set the screen for me at what he considered the 'correct' distance and height. In order to view the screen I had to tilt my head right back so as to be looking at it through the central section of my spectacles. He immediately recognised this and adjusted the screen so that it was lower and closer and comfortable for me. I could see the screen clearly also see what was adjacent to the keyboard.

Isn't the real aim that someone sitting correctly (and comfortably) can work with screen and keyboard without strain?

Chris

there is a programme called cardinus we use for our assessments which is quite good, staff have the training and then complete their own assessments- this is then sent back automatically and you can send advice and report chasers, print of reports of user hazards/issues and what percentage have been improved or resolved

BS EN ISO 9241 Part 5 implies that, a desk depth cannot be less than 800 mm. The optimum eye to monitor distance for a small (15 inch) monitor in the seated position is 600mm. However, users have different preferences and distances between 450mm and 750mm are acceptable.

I do not have access to BS EN ISO 9241 Part 5 so that I can verify the above.

Page 37 of the HSE Guidance, L 26 highlights:-

General approach: Use of standards

3 Ergonomic requirements for the use of visual display units in office tasks are contained in BS EN ISO 9241 There is no requirement in the DSE Regulations to comply with this or any other standard. Other approaches to meeting the minimum requirements in the DSE Regulations are possible. These other approaches may be appropriate if special requirements of the task or needs of the user mean that equipment, software, etc that complies with the standards is not suitable. However, employers may find standards helpful as workstations and software satisfying BS EN ISO 9241 would meet and in most cases go beyond the minimum requirements in the Schedule to the DSE Regulations.

4 BS EN ISO 9241 covers the ergonomics of design and use of visual display terminals in offices; it is concerned with the efficient use of the equipment as well as with user health, safety and comfort. While drafted in connection with office tasks, many of the general ergonomic recommendations in BS EN ISO 9241 will be relevant to some non-office situations.

5 BS EN ISO 9241 is an international standard replacing the earlier, interim British Standard BS 7179 which has now been withdrawn. BS EN ISO 9241 is a multipart standard covering the following:

Part 1 General introduction
Part 2 Guidance on task requirements
Part 3 Visual display requirements
Part 4 Keyboard requirements
Part 5 Workstation layout and postural requirements
Part 6 Guidance on the work environment
Part 7 Requirements for displays with reflections
Part 8 Requirements for displayed colours
Part 9 Requirements for non-keyboard input devices
Part 10 Dialogue principles
Part 11 Guidance on usability
Part 12 Presentation of information
Part 13 User guidance

If your manager does not know that there are significant aspects of GB health & Safety Regulations that are NOT prescriptive, the distance from the screen being one of them, then I am afraid that you will only have "guidance" and not the so called definitive proof-and judgements have to be made. British, European & International Standards may provide additional information on "good practice", but that is what it is.

If you go into Google Scholar and type viewing distance from computer screen you should get a couple of papers come up with research that has been conducted into that. Most are from about 1996/7 so when the legislation first came out. I don't have full access to all the papers (just the summary) but I guess that would probably be the empirical data your boss would be looking for perhaps?

The alternative would be to visit an optician and ask them to provide a written statement giving reading distance for;
paper documents,
screen,
driving test.

I was a consultant ergonomist for 8 years and always explained that when you read a book, most people tend to hold it with their arm about right angles and that the font is between 10-12. This is the optimum reading distance for this size of font. However when the information is on the screen, its about arms length (or longer) so as the day goes on, the eyes can become fatigued trying to focus at this greater length - hence breaks are recommended. Again, the arms length is a rough figure rather than absolute as depends on the person's vision (good / poor / wears glasses / contacts / any other visual issues). There is no "right" or wrong answer as depends on the individual but the documents on Google scholar or an optician should be able to provide you with the medical reasons for this distance.

(p.s. there's always one person that questions or says they've read some report in the Daily Rag that says the best position is this way or that). Ultimately you can only provide them with advice but can't make them do what you've suggested...you just warn them of the consequences (sore neck / back etc) and note on the form what you've recommended. If they come back a year later complaining of a sore back / neck etc from computer use, you can tactfully remind them they were given advice on such a such date and what that advice entailed!