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Tag: fatigue

Scanning versus reading. Is there a difference?

(Yes, and why we prefer scanning over reading may surprise you.)

Scanning; we all do it, especially when scrolling through social media or skimming through a post. We visually bounce from word to word to understand the ‘gist’ of what’s being conveyed.

Scanning involves the internal recognition of letters and words, and it identifies patterns of text. So, it is not necessarily about comprehension (though that does happen).

It closely mimics a user’s natural reading speed for personal consumption, which is important to note. However, reading speed is reduced when the user is asked to read the entire text and then reduced further when reading aloud.

Reading aloud is a less fluid process, as vocalising words lags behind the brain predicting what’s next and modifying what’s being spoken as a result.

Looking ahead can cause incorrect predictions, leading to some stumbling over words, especially for slow readers.

Interestingly, “If you watch a person’s eyes scanning text at a normal rate, the eyes seem to be ahead of the voice when we read aloud.”

Diving deeper into the science of scanning:

Rayner and Pollatsek, two researchers from the Massachusetts Institute of Technology, spent 20 years studying how the eye moves when reading. They discovered that it fixates on what they call content words, e.g., nouns and verbs in a quick succession of stops and jumps called fixation and saccades

A saccade “is a rapid, conjugate eye movement that shifts the center of gaze from one part of the visual field to another. Saccades are used for orienting gaze towards an object of interest. Saccades may be horizontal, vertical, or oblique.”

Imotions.com describe the fixation as “Between saccades, our eyes remain still for around 200-300 ms – this known as a fixation (“still” is a bit of a relative term here – our eyes often continue to move around as a result of optokinetic nystagmus, which aids visual processing in the brain).”

image of text showing eye movement of scanning
Showing the eye focus when scanning

(Image from readingrockets.org )

Why do our eyes jump around like this?

Up-close we have a very narrow field of vision.

Try looking at both of someone’s eyes at the same time without flicking from one to the other. This narrow field makes us very sensitive to misalignment and being uncomfortable when wondering which of their eyes is looking at us.

Even when reading, our eyes move around to take in a larger view.

If you can scan quickly and easily, your eyes are not only seeing the text easily, but you are interpreting the text efficiently and with a degree of visual comfort. 

Reading, on the other hand, is comprehending the words.

If it’s silent reading, it can include creating visual images to help understand the words, and we can often ‘hear’ the word in our heads. So, for example, when you read a novel, you’ll imagine the characters in your mind; you might even imagine how their voices sound.

Reading, primarily when out loud, engages the brain and the vocal system and, to a degree, comprehension.

However, with reading out loud before reading silently, there is a difference in understanding, with a greater degree of comprehension gained from silent reading first.

Ok, so why are we telling you all this?  

When our software is choosing the individualised contrast colour background to text for your digital display screen, we are looking at set data to find the “one” most visually comfortable or accessible colour contrast for you.

One that aids in your scanning and reading.  

The correct colour contrast does this by helping sustain the synchronicity of both eyes, mitigating binocular discomfort and loss of stereoscopic vision due to eye muscle fatigue.

It’s a fatigue that presents as early-onset blurred or double vision.

Different coloured backgounds for the same texts
black text with different coloured backgrounds

Here’s (very simply) how it works:

There are two primary types of photoreceptors in the human retina – rods and cones.

Rods are responsible for vision at low light levels (scotopic vision). They do not mediate colour vision and have a low spatial acuity.

“Rods don’t help with colour vision, which is why at night, we see everything in grayscale. The human eye has over 100 million rod cells. Cones require a lot more light and they are used to see colour.”

Cones are active at higher light levels (photopic vision), are capable of colour vision and are responsible for high spatial acuity.

The correct colour contrast background aids in your scanning and reading by engaging the colour “cones” in the eyes, as opposed to the monochrome rods.

It’s about your individual photopic sensitivity.  

Photopic sensitivity refers to visual sensitivity under conditions of bright light, where radiant energy stimulates the cones  – the retinal photoreceptors responsible for colour perception.

The cones, with their high acuity, are better placed to deal with text but are not invoked by black on white text.

Black text on a bright white computer screen only turns up the volume of any discomfort or fatigue.

Bringing in the colour contrast background brings the cones to the party and help you read and scan much more easily.

Now to your screens:

 The visual system (eyesight) is effectively disabled by “Glare”. Think of how you screw up your eyes and want to look away at bright headlights in the dark.

If there is also photophobic flickering light, or very high contrast and/or very low contrast that causes discomfort, prompting visual stress with avoidance strategies such as looking away, natural “adaptations” due to eyestrain will appear.

They must, as your body is trying to defend itself.

The warning signals of this will be loud and clear – pain, headaches, blurry or worse double vision, dizziness, migraine, even nausea and vomiting.

These signals should not be ignored.  

 Every individual and display screen for that matter is different, so it is simply a question of matching the screen colour contrast settings/calibration to the user operators most comfortable, expressed by RGB background screen colour values or HEX number.

By analysing the eye systems responses, we look for any evidence of eye muscle fatigue. We measure screen to brain sets of functions and timescales – namely the focus and refocus of the eye muscles and look at any deficits in speed when scanning.

We’ve found the simplest way to do this is to use a block of no-sense text. This prevents the individual’s natural capacity “for predicting what comes next”, to allow repeat scanning of the same subject matter without becoming familiar with its content.

“With the DSO scanning challenge, we are looking at specific data points, and we are looking at the speed of scanning, as this simply points towards gains in accessibility, comfort and ease”.

 The gains in accessibility to text on-screen, increase comprehensibility, increase the comfort within your visual system for longer and reduces the risk of early-onset eyestrain, mitigating vision system deterioration.

Until our brains are chipped to interface with our computers directly to the screen, users will still need to use their eyes to read.

Until that day, users contend with screen brightness, glare, colour contrasts, and moving images, all of which can overexcite the visual system and cause fatigue, which leads to all the symptoms of screen fatigue/computer vision syndrome.

We aim to calm the visual system more than aid in dyslexia/comprehension by bringing on board the cones to help the eyes to focus and refocus, not leaving the poor rods to do all the heavy lifting.

That it helps in these areas too is a bonus.

In optometry terms, we aim to increase binocular stability, as we all know looking at a screen for too long causes binocular instability, essentially visual fatigue.

(Anecdotally, we notice an average 20% gain in accessibility/reduction in eyestrain and risk of screen fatigue / CVS by using the DSO, which is being investigated further in our clinical trials.)

What about biometrics?

We currently use AI to drive the DSO, and soon we will be adding biometrics screening and voice recognition to next-generation packages of Score My Screen.

Is your office lighting losing you money?

Poor lighting, flickering lights, too bright, too dim, these all impact our well-being and the company bottom line.

But it’s a surprisingly easy thing to fix.

What is poor lighting?

When we think of poor lighting, we think of dimly lit rooms, even semi-darkness, but a space that’s too bright also qualifies as being poorly lit.

Throw unevenly distributed and or flickering lights into the mix, combine that with the flickering of digital display screens, and together they create a ‘doppler effect’, a well-known hazard in the workplace.

In 2012, Health and Safety International produced an in-depth article related to eye health in the workplace.

The report highlighted a list of factors, and the ability to see well at work depends not only on lighting but also on:

      • The time to focus on an object; fast-moving objects are hard to see
      • The size of an object; very small objects are hard to see
      • Brightness: too high or too low. Reflected light makes objects hard to see
      • Contrast between an object and its immediate background; too little contrast makes it hard to distinguish an object from the background
      • Insufficient light – not enough light for the need
      • Glare – too much light for the need
      • Suboptimal contrast
      • Unequal and poorly distributed light
      • Flicker Poor lighting can cause several problems, such as misjudging the position, shape or speed of an object can lead to accidents and injury
      • Poor lighting can affect the quality of work, particularly in a situation where precision is required, and overall productivity
      • Poor lighting can be a health hazard – too much or too little light strains eyes and may cause eye irritation and headaches

“Optimizing the amount of natural light in an office significantly improves health and wellness among workers, leading to gains in productivity.”

Most papers refer to commercial productivity when looking into office lighting, which is understandable as we work to be productive.

But as we are a company concerned with eye health, we want to look a little closer at the effects lighting has on the eyes.

The studies that looked at ocular health found that poor lighting affects the degree of fatigue on the eyes and overall health.

Workers in office environments with optimized natural light reported an 84 per cent drop in symptoms of eyestrain, headaches, and blurred vision symptoms, which often result from prolonged computer and device use at work and can detract from productivity.

 

The impact of lighting has been documented for hundreds of years in educational establishments, but aren’t offices similar to classrooms? Shouldn’t the lighting be treated in the same way?

There you are in class, sitting in rows, at a desk. There you are in an office, sitting in cubicles, at a desk.  Each situation involves concentration and reading/writing; both probably have sub-optimal lighting.

But let’s first indulge in some lighting talk.

Fluorescent lighting and compact fluorescent light bulbs (an energy-saving version of the former) are familiar to many of us from school and work.

Both are known to cause vision stress, eye strain, dry eyes, double vision, headaches, poor concentration, and increased error rates.

This is due to their production of an artificial source of ultraviolet (not Blue) light known to cause cataracts and macular degeneration, which is why there is now a push towards LED lighting in addition to their energy-saving qualities.

Fluorescent lights may be an old and well-known technology, yet they contain mercury, age significantly when turned on and off (probably why offices leave them running all night – environmental impact anyone?), and are omnidirectional, so the light goes everywhere. Not always the best solution for your eyes.

On the other hand, LEDs have a long life span, are energy efficient, provide high light quality, can easily be directed, and have low maintenance. Plus, you can turn them off without worry if this will kill the bulbs.

The ‘temperature’ of the light is another factor. Warmer light with more of a yellow/orange hue is better for the evening, allowing us to relax and wind down. Office lights are generally ‘cooler’ to help keep us more focused.

Indeed, anglepoise lamp manufacturers are now jumping on the working from the home bandwagon, suggesting ‘warmer’ lighting alongside the daylight from a window, and why not? Lighting in the home office is just as important as the work office.

The window company Velux is now heavily involved in research. As they state on their website, they “are committed to taking a leading role within the building industry to create better environments for working, living and learning”.

Whether an office’s light source is natural, artificial, bright and blue, or dim and yellow, the type of light that employees are exposed to not only impacts mood, circadian rhythms, and physical health but also affects productivity and creativity

The political football

When looking at the lighting in schools, the focus tends to be on mood and concentration, academic performance, and alertness.

Eye strain is barely mentioned, with one website stating that reading in dim light merely tires the eyes but doesn’t cause lasting damage. However, Dr Richard Hobday, PhD, Engineer, and author of The Light Solution, is convinced that poor lighting in schools is triggering myopia, short-sightedness.

A hundred years ago, school designers knew poor lighting caused myopia. Still, in the 1960s, myopia was dismissed as a genetic or inherited condition and had nothing to do with illumination or close-up work.

Currently, myopia is attributed to too much indoor near or close up work, the school environment and lack of outdoor time. Also, in the digital age,  exacerbated by too many hours scrolling on the smartphone.

Hobday writes, “At the beginning of the last century, high levels of daylight in classrooms were one of several measures thought to prevent myopia, and some eye specialists campaigned for what they referred to as ‘ocular hygiene’ in schools. They stated that children had to learn how to see properly, without straining their eyes, if they were to preserve their eyesight.”

Indeed, a recent pilot study from China found that schoolchildren and teachers prefer brightly lit classrooms that reflect more natural daylight. Why mention China? Asia is currently experiencing a myopia rate of 80% in their children.

The solution

Humans have known for hundreds of years that levels of lighting are essential. We know poor lighting is not only responsible for deteriorating eyesight (yes, Granny was right!), but it’s also responsible for fatigue, low productivity, and a decline in wellness.

We receive 85% of our information through our sense of sight.

Therefore, we need optimal lighting in the office and at home. In addition, we need to mitigate the effects of poor lighting and staring at a screen all day.

Optimal lighting is 300-500 lumens.

Lumens (denoted by lm) measure the total amount of visible light (to the human eye) from a lamp or light source. The higher the lumen rating, the “brighter” the lamp will appear.

Whether working from home or in the office, we need lighting adjusted and moved to suit our needs.

Adjusting office lighting and installing systems and features to protect our eyesight will achieve two things.

  • Reduce the levels of visual stress and binocular eye strain.
  • Reduce levels of fatigue and improve levels of productivity.

To conclude: Reduce flickering lights, reduce flickering computer screens,  and invest in a reasonably adjustable LED lighting system. Follow the HSE guidelines and regulations for office workstations and invest in a DSO to prevent screen fatigue.

Much the same way you’d adjust to driving a new car.   The first ergonomic thing you do in a strange vehicle is to change your seat so you can reach the controls safely and make yourself comfortable to reduce stress.  Then you adjust mirrors and find out where the indicator and windshield wiper controls are.

Adjusting the lighting in the home/work office is just as important.