“A lot of what happens in our environment is moving – like trying to cross a busy intersection as a pedestrian or finding something on a shelf as you’re walking through the aisles of a grocery store. Testing visual acuity under dynamic conditions can provide more information about our functional performance in these scenarios than traditional static visual acuity measurements alone,” said co-author of the study Dr Kristine Dalton of the Waterloo’s School of Optometry & Vision Science.
Dynamic visual acuity is crucial for cyclists
The clarity or sharpness of your vision, also known as visual acuity, is your ability to detect and recognize small details. Dynamic visual acuity skills are especially important when you or objects around you are moving. In cycling, it refers to a cyclist’s clarity of vision while in motion or while tracking a moving object. There are a lot of applications for this ability, regardless of what type of cycling you prefer. Here are just a few of the most striking examples.
- Road cycling in a group – You have to rapidly change focus from the cyclist directly in front of you to the cyclist in front of the pack and back to the road to watch for obstacles.
- Downhill mountain biking – You have to be aware of your surroundings while focusing on small details on the trail in front of you to keep adjusting and selecting the optimal path.
- Urban cycling – You have to constantly judge cars and other vehicles passing you and coming towards you when crossing intersections and making turns.
Testing your vision on caffeine
On 2 separate days, half of the study’s participants ingested a caffeine capsule consisting of 4 mg per 1 kg of body weight and the other half got a placebo pill. Using a computer-based test designed and validated at the University of Waterloo, each participant’s dynamic visual acuity skills were measured before and 60 minutes after the ingestion of the pill.
“While we already know that caffeine increases the velocity of rapid-eye movements, we wanted to further investigate how exactly caffeine enhances visual processing and facilitates the detection of moving visual stimuli by testing dynamic visual acuity,” said co-author Beatríz Redondo of the University of Granada’s Department of Optics.
Caffeine improves accuracy and speed when identifying moving objects
The study revealed that participants who ingested caffeine showed significantly greater accuracy and faster speed when identifying smaller moving stimuli. Caffeine seems to be improving stimulus processing and decision-making. Eye movement velocity and contrast sensitivity, which are implicated in dynamic visual acuity performance, were also sensitive to caffeine intake.
“Our findings show that caffeine consumption can actually be helpful for a person’s visual function by enhancing alertness and feelings of wakefulness. This is especially true for those critical, everyday tasks, like driving, riding a bike or playing sports that require us to attend to detailed information in moving objects when making decisions,” said Dr Kristine Dalton.
You can test yourself
If you want to see how your dynamic visual acuity changes with caffeine, you can try a little experiment. First without caffeine. Choose a safe environment with grass or a different slightly bumpy terrain. Locate a sign or make a few yourself and read the individual letters on the sign backwards while riding past them. Try at several different speeds and see how you do. Then do the same thing about 30-60 minutes after drinking a coffee and compare the results.