Wednesday, July 03, 2013

Better vision - occupational lenses for artists

Have you ever heard of occupational lenses for near and intermediate vision?

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.

Occupational lenses


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
What they mean is much less bobbing or tilting of the head to find the best part of your lens to focus on what you're looking at.  

I found regular varifocals to be unsatisfactory for computer vision and opted for single vision lenses - however a much bigger intermediate area for screen / easel distance would seem likely to make a big difference to how useful they would be.

Enhanced near vision lenses


It's also possible to have glasses made with enhanced near vision lenses - with magnification to a specific distance.  This struck me as a much more straightforward solution for miniature artists than wearing the head magnifiers - particularly as the lenses in glasses can then be adjusted for any other optical quirk your eyes might have.  Prescription lenses would then reduce the scope for headaches. I know some artists have obtained these type of lenses as they've found them much easier to use than a freestanding or headband magnifier.

Assessing what sort of lenses are best - the visual task analysis


Unlike normal glasses where the optician is testing your ability to see letters and definition, the nature of occupational lenses means that the opticians needs to know a quite bit more about the nature of your workplace.

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 tip

Take 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 lenses

Here 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.

4 comments:

Sadami said...

Dear Katherine,
Thank u for very helpful info as I wear specs and am about to get new ones. Take care of yourself. I heartily hope you can see well.
Best wishes, Sadami

theartistsday said...

Thankyou Katherine for that most interesting post. At the moment I am juggling bi focals with a pair of computer glasses. It never occured to me that you could have glasses made to your specific needs. I paint at an easel and never seem to have the right focus.

Cindy Schnackel said...

Yes, I have "computer glasses" that are similar to a mid range correction for distance. My progressive (tri-focal) glasses have never worked for the computer. The mid range area is never in the right place or big enough and causes neck strain, so I have a separate pair by the computer, just for that purpose. They work for art, too, as it's about the same distance range. I had a very hard time getting an eye doctor to make them. But once they did, working on the computer got a lot better!

Vicki Lee Johnston said...

I took my botanical artworks in to my eye specialist (especially the artworks with dissections) and he worked with me to prescribe the bifocal occupational lenses. I did not want to wear these but I can see how by just dropping my eyes to work and looking up I will get the desired medium distance and magnification I need in one pair of glasses. It is very difficult for botanical artists to see the detail at the varying distances without some assistance for each purpose, I am really happy with them but it takes a little getting used to moving your eyes up and down rather than your head to view through the appropriate lens. Great article!



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