It can be all too easy to take our eyes for granted. That is, of course, unless you have an ongoing condition which requires a form of corrective action or in some cases a lifestyle change. In fact, according to the NHS, there are some two million people living with sight loss in the UK of which around 360,000 are registered as blind or partially sighted.
Did you Know? If we saw a wider spectrum then all sorts of strange things would occur, such as not being able to see through rain?
But whether you have 20/20 vision, wear corrective glasses or lenses, or are managing sight loss, how much do you know about your eyes? How are eyes formed? Do they simply tell us about the world around us; or can they speak volumes to opticians and others about our general state of health? We’ll be examining these topics in more detail in future articles. But for now let’s have a quick look at a few interesting facts which you may not know about how your eyes work.
It’s all about light; but it has to be the right sort of light. What we see starts with light being reflected from an object and towards our eyes. That reflection then passes through a succession of layers in your eyes which are designed to collect and focus the light before translating it into a signal which can be interpreted by your brain. Human eyes are tuned to what we call the visible part of the light spectrum which enables us to see those parts of the world around us that we need to interact with. Did you know that if we saw a wider spectrum then all sorts of strange things would occur, such as not being able to see through rain?
Seeing in colour. At the back of our eyes the retina contains two different types of receptors that are responsible for translating the light into signals for the brain. Rods work at low light levels and only deliver black and white images but they can help us to interpret objects and to move around darker conditions. Cones need brighter lights and are responsible for translating colours and sharper images. But…
…Watch out for your blind spot. Where the optic nerve which takes signals to the brain connects with the retina there are no rods or cones. This creates a small blind spot in each eye. Normally this is not a problem as each eye compensates for the blind spot in the other eye. But where the other eye is obstructed, perhaps by a pillar, the blind spot can mean that you just don’t see objects. That’s why it’s good driving practice to move your head around particularly when looking to see if it is safe to pull out of a junction. This is especially true at night when relying on rods which are further out from the centre means the blind spot could be as much as five or ten degrees of vision.
Understanding our eyes can therefore help us to move safely around and interpret the world. However, the pioneering work which our team and others are doing also reflects the other way; looking into our eyes to diagnose health conditions such as diabetes.