Fascinating Eye Facts

A quick peek into the wondrous world of our eyes…

Our eyes develop early: Our eyes begin to develop a mere two weeks after conception and by the end of the first trimester, the basic structures of the eye are in place. Eyelids develop around week 10 and fuse shut – remaining closed until closer to birth.

We see upside down: Everything we see actually lands on the retina inverted, which the brain then flips and adjusts, presenting us with the ‘right-side-up’ world we know. This is thanks to the cornea, which is curved, so it bends the light entering the eye, creating an upside-down image on the retina.

Colour chameleons: We can see millions of colours, thanks to special cells called ‘cones’ that come in three different types, sensitive to red, green and blue light. Colour blindness, unfortunately, is caused by malfunctioning or missing photoreceptor cells in the retina. The most common form is red-green colour blindness. Less common types include blue-yellow colour blindness and complete colour blindness (monochromacy), where people see the world entirely in shades of grey. While there’s no cure for colour blindness, special glasses or contact lenses can sometimes help people differentiate colours more easily.

Not quite round: The human eyeball isn’t perfectly round but slightly oval-shaped, which creates a wider field of view. This allows us to take in more information about our surroundings at a glance, and is particularly useful for depth perception and peripheral vision. The back of the eyeball also needs to accommodate various structures like the optic nerve and blood vessels. The oval shape provides a more efficient way to pack all these essential elements in.

Blink, blink: We blink an average of 20,000 times a day. Blinking might seem like a lazy eye exercise, but it’s actually crucial for keeping our vision sharp. Each blink only lasts for about 0.3 seconds and the brain uses these ‘blink breaks’ to process visual information, stitching together the world around us.

The blind side: We all have a small blind spot where the optic nerve connects to the retina. Luckily our brains fill in the gap, so we don’t notice it. Try this: Hold your thumb at arm’s length and close one eye. Focus on a point beyond your thumb, then slowly move your thumb across your line of sight. At some point, your thumb will disappear. That’s your blind spot.

Fingerprint look-alike: The iris, or coloured part of your eye, is as unique as a fingerprint. Your genes play a major role in determining the basic colours and patterns of your iris. Tiny freckles, streaks and colour variations all contribute to the overall pattern, making it highly individual. Iris recognition technology uses sophisticated algorithms to analyse these intricate details and create a unique ‘iris code.’ This code is even more distinctive than a fingerprint, making iris scanning a highly reliable form of biometric identification today.

Types of tears: We have three types of tears: basal tears (these lubricate the eye surface constantly and are essential for healthy, comfortable eyes), reflex tears (a reaction to irritants, like dust, smoke or strong fumes) and emotional tears (triggered by feelings and believed to contain additional proteins and hormones compared to other tear types). Recent research suggests there might even be a fourth type of tear – empathy tears – shed in response to the emotions of others, fostering compassion and social connection.

Our eyes really are marvels of biology and evolution, constantly processing and interpreting the visual world around us. And remember, if you ever have any concerns about your vision, we’re just a call away.