by Jamie Bartlett October 12, 2021 7 min read
Occupational lenses is a collective term for varifocals, designed for close to intermediate tasks such as reading, writing and screen-work. These lenses can be either ‘office’ or ‘computer’ varifocal lenses which differ in their focal capacities.
To help you decide on which lenses are right for you, this article explains the three main types of varifocal lenses you should know about.
Everyday varifocals are used for any of the three vision zones which are defined as close, intermediate or distance. They are a “one lens does all” helping you avoid having multiple pairs of glasses.
Everyday varifocals are great for many scenarios, from close-reading notifications on your phone to distance-viewing the road when driving. A jack of all trades.
However, they aren’t so good for occupational tasks as they tend to have quite a narrow intermediate “corridor.” Looking through an everyday lens, there isn’t much lens-space for you to look through when using a computer, reading or writing.
In the illustration below, you can see the functional focal area of an everyday varifocal lenses and its relatively narrow corridor.
Office lenses, also called office progressives, are a supplementary varifocal lens designed primarily for close to intermediate use with a very limited distance capacity of 4m.
Specifically, office lenses are optimised for occupational work involving reading, writing and computing.
The drawback of occupational varifocals is they’re limited to a maximum distance vision of about 4m. You won’t be able to focus on anything beyond this distance which makes them completely unsuitable for driving.
This is why occupational lenses are always used a supplementary pair of glasses in addition to ones that can help you with distance viewing.
In the illustration below, you can see the benefits of a much broader intermediate corridor through occupational lenses.
Computer lenses, also called computer progressives, are a supplementary varifocal lens designed solely for close to intermediate use with no distance vision capacity.
Like office lenses, computer varifocals lenses are optimised for reading, writing and computing but are limited to intermediate vision only.
You won’t be able to focus on anything much further than arm’s length, thus making them more limited than office varifocal equivalents.
Computer varifocal lenses are a popular option as they’re more specialised than office lenses for close to intermediate work.
Computer glasses can mean one of three things. Single vision intermediate lenses, computer varifocal lenses or blue light blocking lenses. Any of these options are designed for screen-work to aid occupational tasks.
As you can tell, computer glasses are a mixed terminology.
Sticking to varifocals, are progressive lenses good for computer work?
If you regularly work on a computer, investing in computer or office glasses with can help you in a number of ways.
Computer or office progressive lenses are specifically designed to maximise the amount of intermediate lens-area you can see through. They have a much broader focal corridor which can help improve your working comfort at your desk.
With an enlarged intermediate lens-section, you won’t need to tilt your head backwards to see through the middle or bottom of your lenses for screen work.
This is one of the biggest postural benefits of occupational varifocals as they can prevent the habit of tilting your head to see nearby objects such as your computer screen.
According to an article by Ergorisk, long durations of computer work with head-tilt can cause neck or back pain, potentially leading to further muscular implications.
In additional to postural benefits, you might want to consider the addition of an anti-blue light lens coating on your lenses.
For intensive screen-work, this add-on may help reduce the eye-strain experienced from long durations at your computer. This is due to the HEV (high energy visible) light which emits from digital screens such as laptops, monitors and mobile phone screens.
As seen in the image below, HEV is part of the visible spectrum of light which emits from the sun and also from the screens of digital devices.
Whilst there isn’t any credible evidence to support the use of blue light blocking glasses, they are capable of absorbing blue light which may help to alleviate irritation and eye fatigue.
According to an article by the Optometry Times, the largest concern about the unknown effects of HEV light is the onset of premature aging of the eyes. Otherwise called macular degeneration.
Because we’re all spending so much time looking at screens, there’s concern for the potential damage caused by prolonged screen exposure.
Due to their specific usage, progressive office lenses have their disadvantages.
Cost: The stronger your prescription, the more likely you are to require a thinner lens with a higher refractive index.
If you have a particularly strong sphere (SPH) in your prescription, you will benefit from a high index lens to prevent having cumbersome lenses which are heavy, thick and may protrude from the edges of your glasses.
As a rule of thumb, the higher the index, the higher the price of your lenses.
For guidance choosing the correct lens index click here.
Just for the office, occupational lenses are limited to close to intermediate visual tasks. Which for you, might seem a lot of money for a very specific pair of glasses. If you rely on good intermediate vision in order to do your job, office lenses may have to become part of your eyewear arsenal.
Two pair of glassesmay seem a little excessive but it’s a common solution if you struggle with close and distance visual focus.
Generally speaking, your near vision starts to show signs of deterioration at the age of 40 or so. This is due to the onset of presbyopia which inhibits your eyes to focus on close distance tasks like reading text messages on your phone.
Reading glasses are a good solution for this but are totally unsuitable for computer work. This is where a varifocal lens can help as they’re give you more focal capacity for multi-distance tasks.
Not for driving: Because office lenses are limited to a maximum distance of focus of about 4m or so, they are completely unsuitable for driving. Instead, you should consider a single vision lens for distance vision to aid you for this.
If you’re new to wearing varifocals, the costs can seem comparably high compared to other lens types. This is for three main reasons.
To summarise, office lenses can definitely help you.
At work, they can improve your working posture by improving your seated position whilst using your computer.
Office lenses are a good preventative for head-tilt, which is a common side-affect from using everyday varifocal lenses.
This is the most assured benefit of investing in occupational lenses if you’re willing to have a second pair of glasses to wear for near to intermediate vision tasks.
Less assuredly, office lenses with an anti-blue light coating is a secondary benefit which you can choose to have added to your office lenses. The evidence on the efficacy of this coating is still yet to be confirmed can give you piece of mind knowing you’ve made a step to reduce the effects of HEV light from your computer screen.
For 8 hours a day, 5 days a week, office lenses are arguably a worthy investment if you want to improve your visual working comfort. Outside of work, other near to intermediate tasks such as cooking can be improved thanks to a larger intermediate corridor.
Hopefully, you’ve found this article useful towards making your decision about office lenses. If you’d like to learn about the best ways to order varifocals online, you should check out my other helpful article which shows you how to do this.
Thanks for stopping by.
by Jamie Bartlett October 04, 2021 7 min read
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