How Your Mood Can Change the Way You See the World
Our vision is generally considered to be separate from our emotions. After all, no matter our mood, we all still see the same view of the world, right? Or do we? While we might all be familiar with the terms “rose-tinted” glasses, or “green-eyed monster”, it’s easy to dismiss these as simple sayings that don’t hold much stock. However, some evidence indicates that our emotional state may impact our vision more than we might have thought.
Our eyes are one of the most complex organs in the human body – second only to the brain. They are made up of over two million components that work tirelessly to provide us with an accurate depiction of the world around us. But as it turns out, our emotions may sometimes skew this accuracy.
What does the research say?
A significant amount of research has been conducted on this topic, with many studies yielding fascinating findings. For example, a review of the existing evidence published in 2012 noted evidence indicating that humans tend to overestimate the steepness of hills: while an incline may only be five degrees, we may interpret it as 20 degrees or more! Moreover, some evidence suggests our perception of said incline may change depending on our mood, appearing steeper when we are sad than when we are happy.
Other findings suggest that the desire to achieve a goal can make goal-relevant objects appear larger, while fear can affect our low-level visual processes. Furthermore, evidence also indicates that depressive episodes can have a significant impact on how we see the world.
Depression and Contrast Sensitivity
In 2013, researchers at the Department of Psychiatry, Singapore General Hospital, published their findings comparing visual contrast sensitivity in individuals with major depressive disorder with those without. Having completed testing in 20 individuals in each group, the researchers found that subjects with depression had reduced visual contrast discrimination performance, indicating a neurological link between depression and visual contrast sensitivity.
Later research, published in 2021, supported these findings. Comparing patients who had baseline major depressive episodes with control participants who did not. Participants were presented with simple visual patterns made up of squares and stripes in different shades of grey.
It was found that contrast suppression was significantly lower for individuals experiencing a depressive episode. Moreover, on follow-up (i.e., when patients were in remission), the differences in contrast suppression appeared to normalise.
What is Contrast Sensitivity?
Contrast sensitivity is an important factor that contributes to the overall quality of our vision. In fact, you can have 20/20 vision – as measured by the crisp black letters on the white Snellen chart – but still have trouble distinguishing shades of the same colour.
The world is full of shades of grey (especially during winter), and it is important to also measure contrast sensitivity. People hampered by low contrast sensitivity will have problems seeing distinct images in certain conditions. For example, in dim city streets, low contrast sensitivity can cause a person to trip on a curb when they are unable to differentiate between the edge of the pavement and the road.
It can also cause problems when driving at night with the possibility of not seeing pedestrians wearing dark colours.
Contrast Sensitivity and Laser Eye Surgery
Maintaining a good level of contrast sensitivity is an important consideration when performing Laser Eye Surgery. As our expert surgeon, Mr Glenn Carp, explains:
“In laser terms, if you have x amount of contrast before surgery, it should measure exactly the same after the operation – usually no better and certainly not any worse”, explained Glenn. “It is a matter of improving the quantity of vision while maintaining its quality.
“If it is lower for any reason after surgery – although this is rare with modern lasers – we would treat those components and then it would revert to how it was before.
“That is why we measure contrast sensitivity at the three-month check-up – not after one month – because it needs time for any residual swelling or dry eye to settle down. This is why, sometimes, in the early days after Laser Eye Surgery, night vision might appear a bit fuzzy.”
If you’s like to learn more about our pre- and post-operative testing, get in touch with one of our friendly clinic coordinators. Alternatively, to start your Laser Eye Surgery journey, Book a Consultation today!
