I learned something new when I visited my optician yesterday to get new prescriptions for intermediate and reading distances following my eye surgery (see Normal vision will be resumed as soon as possible).
I commented that I'd been thinking of having a pair of bifocals for computer and reading vision - but wanted to wait to see how I got on with my new computer glasses for occasional reading.
The optician told me that if I did a lot of reading at the same time as computer work I might be better off having some specific occupational lenses. (Interestingly this is a topic which has not yet found its way onto Wikipedia!)
She told me that these are typically used by people who work with different and relatively short distances in their immediate workplace - basically any working situation where the emphasis needs to be very much on the whole of their near and intermediate vision.
People who benefit are crafts people like watchmakers, jewellers where the near sight can then be magnified to the level required for the precision and details required and the intermediate used for their vision of their workbench.
Occupational lenses are also commonly used by office workers whose working day is dominated by having to read (looking down - near) and use a computer screen (intermediate) at the same time. Some of these are bifocals and others are varifocals.
It struck me that this is a solution for the many artists who work in a studio with repeated use of similar distances - such as the botanical artist working from life (ie why I was asking!)
I found this blog post Glasses for the office by Neil Dixon (stuph...) to be very useful to understanding how they work. It's by somebody who had occupational lenses prescribed for the office but found them particularly beneficial for his leatherwork as well. His diagram is very helpful.
|Diagram by Neil Dixon which contrast regular varifocals with occupational varifocals|
Enhanced near vision lenses
Assessing what sort of lenses are best - the visual task analysis
The following is an abbreviated extract from Occupational Dispensing - a detailed guide for dispensing opticians. It highlights the sort of issues a dispensing optician needs to consider.
Visual task analysis
Before spectacles can be dispensed for occupational reasons, it is important to first conduct a visual task analysis to determine the patient’s specific needs. The primary details that need to be elicited are:
- Task size – consider the size of the text/task and the field of view;
- Working distance (WD) – this will dictate the power of the near addition and the range of distances which need to be catered for.
- Lighting – accurate perception needs optimum lighting, especially when reading, writing, driving and using a VDU.
- Contrast – black writing on a white background gives the best contrast so consider the patient’s tasks as to whether there will be difficulty in seeing objects in the work area;
- Colour vision – this is imperative in some occupations so lenses prescribed must be of a suitable material in order to maintain the quality of colour perception and not induce chromatic aberrations.
- Stereopsis – the ability to judge depth is vital in certain occupations
- Whether the task is still or moving
- The position of the patient and the task – the occupation may involve moving around the working environment and so the lens dispensed ideally should cater for this or at least not cause inadvertent increased risk of injury.
- Possibility of hazard - the dispenses lenses must provide adequate protection
My tipTake the guesswork out of a consultation with your dispensing optician and provide facts! A very good way of giving the optician the sort of information they need is to:
- Take a few photos of where you sit/stand and where you work - to show the nature of the set-up in your immediate working environment
- Record measurements relating to the typical distances between your eyes and things you need to see clearly. Get a long ruler or somebody to help out with the measuring.
- Do some diagrams which show your normal set-up and the distances involved.
More information about occupational lensesHere are some links to websites which provide more information about occupational lenses. This is by no means an index of best articles. I'm also NOT recommending the lenses identified so much as recommending the articles as a way of understanding more about how such lenses can help artists and the options on offer. Your best way forward if you think this is something you'd like to know more about is to have a detailed discussion with your optician.
- Occupational Dispensing - a detailed guide for dispensing opticians
- IPC Office - the best lens for office work
- Occupational Lenses - how they work
- What are occupational lenses
- Standard and modified occupational multifocal lenses
- Nikon - The perfect enhanced intermediate vision lens for home and office - focuses on enheanced near vision lens and has a good diagram of the way different types of lenses work
- Neil Dixon - Glasses for the office