Hygeia Eye-Strengthening Chart
– Colour, Focus & Eye Relaxation Exercise
A simple five-minute eye exercise using colour, visual focus, relaxation
and complementary after-images – particularly relevant for eyes that spend long
hours reading or looking at computer and phone screens.
The Hygeia Eye-Strengthening Chart was developed from many years of practical work with colour, light, vision and human perception. This unusual eye exercise chart combines changes of visual attention with complementary colours, after-images and periods of relaxed looking.
In today's screen-based world, our eyes can spend many hours focusing at similar close distances while using computers, phones and tablets or reading. The Hygeia chart offers them a very different kind of activity – a short daily visual focus and eye relaxation exercise involving colour, distance perception and visual rest.
How to Use the Hygeia Eye Exercise Chart
Display the chart somewhere where you can see it comfortably and where there is good, preferably natural, light.
Some people put their eye exercise chart on a bedroom or office wall. Others have traditionally used it while relaxing in the bath, or placed it on a bathroom or toilet wall where they will naturally see it every day.
Choose somewhere where you can sit or stand approximately 80 cm to 160 cm (about 3 to 6 feet) from the chart.
The 5-Minute Eye Exercise
The most important principle is relaxation.
Do not stare intensely or strain to see anything. Allow the eyes to rest naturally on the colours.
If you normally wear glasses or contact lenses, the original Hygeia instructions suggest doing the exercise without them, provided you can see the chart comfortably and can do so safely.
Rest your eyes on each section for approximately 20 to 30 seconds:
- Turquoise-blue – approximately 25 seconds
- White centre / after-image – approximately 25 seconds
- Red – approximately 25 seconds
- White centre / after-image – approximately 25 seconds
Repeat steps 1 to 4 approximately four to seven times.
Always finish with the turquoise-blue followed by the white centre.
A complete eye exercise normally takes around five minutes.
Eye Relaxation – Don't Strain
During the exercise, try not to make an effort with your eyes. This is as much an eye relaxation exercise as an exercise in visual attention.
If you notice tension around your eyes, consciously soften your gaze, blink naturally and allow the muscles around the eyes to relax.
The original Hygeia approach placed considerable importance on the connection between physical relaxation, visual attention and perception. Regular, gentle practice is more important than intensity.
Complementary Colours and Visual After-Images
After looking at one of the coloured sections and then moving your gaze to the white centre, you will normally begin to see a visual after-image in the complementary colour.
Colour after-images are a normal phenomenon of human vision.
Do not try to hold the image there. Simply look with a relaxed gaze and observe how the complementary colour appears, changes and gradually fades.
If your attention wanders, the after-image may disappear. As your gaze settles again, you may notice it returning.
For Hygeia, this was more than simply an optical curiosity. The colour exercise was also used as a way of becoming more aware of the transition between outer seeing and inner visual perception.
Why Does the Eye Chart Use Red and Turquoise-Blue?
The two contrasting colours were deliberately selected in the original Hygeia colour and light work to create very different visual experiences.
Red tends to have an advancing, nearer quality in human colour perception, while turquoise-blue can give a more receding, expansive or distant impression.
Interestingly, the physical distance between your eyes and the chart never changes, yet the experience of looking at these two colours can feel distinctly different.
The eye chart therefore encourages repeated alternation between different forms of visual focus, colour perception, attention and release.
Eye Exercises for Computers, Phones and Screen Use
Computers, tablets and smartphones can keep our eyes occupied at a relatively close and fixed distance for long periods. This makes regular changes of visual distance particularly worthwhile for people who spend much of their day looking at screens.
Whatever other eye exercises you use, one of the simplest habits is to look away from your screen regularly and allow your vision to extend
naturally into the distance.
A window overlooking trees, hills, sky or another distant view is ideal.
The Hygeia Eye-Strengthening Chart provides another short change from prolonged close-up screen work by combining colour perception, visual attention and relaxation.
The original Hygeia material also suggested experimenting with turquoise-blue as a computer highlighting colour because of its visually expansive quality.
Natural Light, Fluorescent Lighting and Our Eyes
The quality of light to which our eyes and bodies are exposed matters.
At Hygeia, light was never regarded simply as illumination measured in lux. Its colour spectrum, rhythm, quality and our human response to it were considered important.
Traditional fluorescent lighting is a very unnatural form of light when
compared with sunlight. It is generated by an electrical discharge through mercury vapour and phosphor coatings, producing a spectral distribution and temporal behaviour quite different from natural daylight.
Sunlight provides a broad, continuously changing spectrum of light and varies naturally throughout the day. Fluorescent light, by contrast, is artificially generated and its spectral composition depends upon the particular phosphors used in the lamp.
Natural daylight remains the reference point against which artificial
lighting should be judged. Measurements such as lux and colour temperature are useful, but they do not by themselves describe the complete quality of the light that reaches our eyes.
Fluorescent Lighting, Flicker, Headaches and Eyestrain
Traditional fluorescent tubes operated from a conventional 50 Hz mains supply can produce substantial light modulation at approximately 100 times per second.
Although this fluorescent-light flicker is often too rapid to be consciously seen, that does not mean that the eyes and nervous system are unaffected by it.
A particularly interesting double-blind study by A. J. Wilkins and colleagues investigated fluorescent lighting, headaches and eyestrain by comparing conventional fluorescent lighting with fluorescent lamps operated electronically at much higher frequency.
The researchers found that the average incidence of headaches and eyestrain was more than halved under the high-frequency lighting in which the 100 Hz modulation had been greatly reduced.
Interestingly, the researchers also found that headaches tended to decrease on higher floors of the building, where there was greater access to natural light.
Fluorescent Light versus the Natural Daylight Spectrum
Another important difference between fluorescent light and sunlight can be seen when different light sources are examined spectroscopically.
Sunlight provides a broad and continuously varying spectrum. Traditional fluorescent lamps produce light through particular phosphors and therefore have a different and less continuous spectral distribution.
Modern lamps have improved considerably, and different fluorescent and LED lamps vary enormously in spectral quality. Nevertheless, two artificial lights with a similar measured colour temperature can still have substantially different spectra.
This is one reason why numerical descriptions such as colour temperature or lux do not necessarily tell us everything about the experienced quality of natural and artificial light.
Classroom Lighting, Children and Learning
The relationship between classroom lighting, daylight and children has been investigated for many decades.
The results are interesting, although the research does not justify claiming that one particular lamp will automatically produce a particular improvement in every child.
A two-year Canadian study led by Warren Hathaway compared children educated under four different lighting systems, including ordinary cool-white fluorescent lamps and full-spectrum fluorescent lighting.
The researchers reported differences in academic achievement, attendance, growth and development between the groups. The study has subsequently attracted methodological criticism, particularly because lighting conditions could not be completely separated from other differences between schools, so its results should be interpreted with appropriate caution.
Another study, by Rikard Küller and Carin Lindsten, followed approximately 90 Swedish schoolchildren for a school year in classrooms differing in access to daylight and fluorescent lighting.
They found differences in physiological patterns associated with the different lighting environments and concluded that windowless classrooms should be avoided for permanent use.
Natural Daylight and School Performance
One particularly large investigation is worth mentioning because it may also explain a figure frequently quoted in older literature about classroom lighting and educational performance.
The Heschong Mahone Group daylighting study analysed approximately 21,000 school records and more than 2,000 classrooms in three school districts in the United States.
It found a statistical association between greater classroom daylight and faster educational progress.
Students in classrooms with the most daylight progressed approximately 20% faster in maths and 26% faster in reading than those in the least daylit classrooms in one analysis.
When window size was examined, pupils in classrooms with the largest windows progressed approximately 15% faster in maths and 23% faster in reading than pupils in classrooms with the smallest windows.
This does not mean that simply removing fluorescent tubes will automatically improve children's performance by 15%. But it does provide substantial evidence that natural daylight and the classroom lighting environment deserve serious consideration.
Natural Light and Visual Wellbeing – What We Recommend
Whenever practical, make generous use of natural daylight.
If you spend many hours under artificial lighting, pay attention to your own experience. Some people notice very little difference; others find particular types of fluorescent or LED lighting distinctly tiring or unpleasant.
Where artificial lighting is necessary, look for good-quality lighting with low flicker, good spectral characteristics and comfortable levels of glare.
And whenever possible, give yourself regular opportunities to go outside, experience natural daylight and allow your eyes to look naturally into the distance.
For balance and wellbeing, we also favour plenty of healthy exposure to natural daylight during the day and a genuinely dark environment for sleep.
Research & Further Reading – Light, Eyes and Visual Wellbeing
For readers interested in exploring some of the research into fluorescent lighting, natural daylight, eyestrain and classroom lighting discussed above:
Wilkins AJ, Nimmo-Smith I, Slater AI & Bedocs L (1989)
Fluorescent lighting, headaches and eyestrain.
Lighting Research & Technology, 21(1), 11–18.
A double-blind crossover study in which headaches and eyestrain were more than halved under high-frequency fluorescent lighting with substantially reduced 100 Hz modulation.
Read the research on fluorescent lighting, headaches and eyestrain
Küller R & Lindsten C (1992)
Health and behavior of children in classrooms with and without windows.
Journal of Environmental Psychology, 12(4), 305–317.
A year-long investigation of approximately 90 children examining daylight, fluorescent lighting, physiological measures and classroom environment.
Read the classroom daylight and children's health study
Hathaway WE (1995)
Effects of School Lighting on Physical Development and School Performance.
The Journal of Educational Research, 88(4), 228–242.
A two-year comparison of different classroom lighting systems and measures including achievement, attendance and development.
Read the school lighting research abstract
View the ERIC research record
Hathaway WE et al. (1992)
A Study into the Effects of Light on Children of Elementary School-Age
– A Case of Daylight Robbery.
The earlier detailed research report describing the two-year classroom study.
Read the research report on light and schoolchildren
Heschong L / Heschong Mahone Group (1999)
Daylighting in Schools: An Investigation into the Relationship between
Daylighting and Human Performance.
An analysis involving approximately 21,000 pupil records and more than 2,000 classrooms examining relationships between natural daylight and educational progress.
Read the daylighting and school performance report
Using the Hygeia Eye-Strengthening Chart Responsibly
The Hygeia Eye-Strengthening Chart is intended as a visual exercise and wellbeing aid.
It is not intended to diagnose, treat or correct an eye disease or medical condition and is not a substitute for professional eye examinations or advice from an optometrist, ophthalmologist or other suitably qualified healthcare professional.
If an exercise causes discomfort, pain, dizziness or unusual visual symptoms, stop using the chart and seek appropriate professional advice if necessary.
Hygeia Eye-Strengthening Chart
Material: Printed paper card
Total size: 60 × 25 cm
Format: Folds into three sections
Approximate eye exercise time: 5 minutes
Weight: approximately 60 g
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