Tennis on the telly…
My mum is one of millions avidly following Wimbledon tennis this week. The soft thwack of a felted ball on a racket followed by a shimmer of genteel clapping and the hushed murmur from the commentary box have been the soundtrack to my early summers for as long as I can remember.
Mum’s often so engrossed in the game that she doesn’t notice that dusk has fallen and the TV is a big bright square floating in a dark room. She finally gets up, stiff and wobbly from sitting still so long to make a cup of tea and head to bed.
So what’s that got to do with the lights?
Most of the research on how to keep our eyes happy and healthy is carried out at the desk with healthy students, not in an armchair where many older adults spend much of their day. The TV is so often the main feature of the living room in many care homes I visit, with resident chairs arranged around a screen without considering what they can see.
Here are three things that might help to keep them comfortable while they watch – and safe when they stand up…
- Balance – 65:35 screen to space
Your eyes are optimised for a natural balance of brightness across a scene that shifts progressively as the sun moves in the sky, and not for a glowing reflective surface, completely independent of the rest of the room – Investigation of the Optimum Display Luminance of an LCD Screen under Different Ambient Illuminances in the Evening. Older eyes are even less flexible than younger ones and naturally more susceptible to glare and confusion from reflections, too. So during the day, turn up screen brightness settings to max and add plug-in lights with shades on either side of the TV- ideally bouncing off the wall behind – to create a more comfortable luminance range without creating distracting reflections or glare – Achieving visual balance for screen-based tasks in multifunctional bedrooms: roles of task illuminance, correlated color temperature, and color rendering. Consider adding open-mesh net curtains to windows to reduce distracting reflections without cutting out daylight altogether. If you can, sit in their normal position to get a sense of what might work best. - Distance – 1:5 screen width to distance to chair
The guide for healthy adults so your eyes can comfortably see the picture not the ‘dots’, is one to five – take the width of the screen and multiply by five to get the optimal viewing distance. That will also help to balance brightness across the visual field. But you may need to adjust that ratio to accommodate changes in vision and personal preference. Investing in a better-quality screen or an anti-glare cover will help. But simply asking what they prefer and adjusting the position of the chair is a good place to start. - Viewing angle: eye level with the top of the screen
When we’re concentrating on a topspin serve – or a spreadsheet – we tend to make more incomplete blinks/only partially close our eyes, and do that less often (around half as much compared to relaxing or chatting – Effects of ambient illuminance and mobile phone screen brightness on tear film stability, visual fatigue, and blink patterns during reading. That lack of natural hydration is one of the main reasons we get from dry and itchy eyes after spending time on screen. The lids of older eyes tend to lose muscle and elasticity, so they tend to droop, partially blocking the pupil and field of view – The aging eye: when to worry about eyelid problems. As well as using the ad breaks to give the eyes a rest and making sure there’s water or a cup of tea on hand, setting up the screen so the top of the screen is level with the eyes means that less of the eye is exposed to the air, improves blink efficiency and helps to counter the reduction in the field of view.
Three surprising tennis facts…
Keeping their eyes on the ball – but which kind of ball counts.
- We know that elite athletes’ eyes learn to anticipate movement, improving speed and efficiency of ’saccades’. But it turns out that co-ordination between eyes, or convergence is altered by training too. Sports with a small ball and action close to the head like tennis have better binocular convergence, while soccer players don’t – Interocular Timing Differences in Horizontal Saccades of Ball Game Players.
- Elite players’ brains commit to a return before the ball is even hit. EEG research on professional players found measurable anticipatory brain activity as early as 42 milliseconds before racket-to-ball contact on a serve – The role of action anticipation in specific sport performance: A three-level meta-analysis and systematic review in temporal occlusion paradigm.
- Tennis balls became fluorescent “optic yellow” in 1972, not for players but for television. Optic yellow sits close to where the human eye is naturally most sensitive in daylight. But this fascinating paper points out that, under LED lights, especially with warmer colour temperatures, white balls might be better after all – Visibility of sports balls with different correlated colour temperatures.