Winter eyes

It’s that time of year when we start to feel dry, itchy,

Colour Blindness

Red-green and blue-yellow colour blindness is actually more accurately known as “colour vision deficiency” because you are not actually blind.

The incredible uniqueness of eyes

The incredible uniqueness of eyes

There’s a fair deal of romance associated with our eyes. Whether you catch someone’s eye from across the room, fall in love at first sight, or stare directly into the windows to their soul, eyes are often at the centre of human connection. 

What’s interesting is that, while it was long thought that our fingerprints were our most unique markers, our eyes are actually a far more personalized feature. Their incredible uniqueness has contributed to the rise of iris identification and retinal mapping as a replacement for fingerprints. In terms of human complexity, our eyes are second only to our brains. And while the pads of our fingers have 40 unique characteristics, our eyes each display an amazing 256…and that’s just what we know of so far.

Looking into your loved one’s eyes may be more intimate than you ever realized. Keep reading to find out about how fascinating our eyes actually are—and how they can reveal information about your health that make comprehensive optometry examinations an essential part of maintaining your overall wellbeing. 

What is your iris?

When we consider what makes our eyes unique to us, we tend to think about our irises. These are the coloured centres of our eyes, where we have muscles that control the diameter of our pupils. By doing so, our irises allow light to enter our eyes, where our lenses focus it onto light-sensitive tissues at the back, called retinas. Our retinas have photoreceptors that enable the light to be translated into electrical signals that travel to our brains, allowing us to see images. 

It’s the uniqueness and beauty of our irises that tends to stand out. Even from a young age, children are fascinated by eye colour, and often add vivid details to their drawings to depict the various eye colours of their family members. 

Pigmentation in our irises can reveal a wide range of colours from blue to brown, including various shades of grey, green, amber, and hazel. The colour of our irises is determined by our genetics, and results from deposits of melanin. The more melanin in your irises, the more your eye colour will trend towards brown, while lesser amounts are found in shades of blue. 

The genetics involved are very complex, involving multiple genes and the potential for disorders that cause albinism. Very rarely, an individual can even have two different coloured irises, as a result of genetics, disease, or injury. This condition is known as heterochromia. 

How unique are our irises? 

The ability our irises give us to see, and their unusual and striking beauty, just scratch the surface of how interesting our irises actually are. Of arguably greater interest is their intricately detailed texture, which remains remarkably stable over time. 

While iris colour results from pigmentation, it’s the exceptional patterning of our irises that lends them most of their distinct characteristics. This happens during fetal development, when random morphogenesis is thought to cause the tissues to tighten and fold. The variations that occur because of this mean that even identical twins don’t share identical irises, nor do our own two irises look exactly alike. 

This individualization in our eyes makes iris recognition one of the most accurate of all the biometric scans available, enabling effective identification from metres away. There’s research underway to continue to improve and perfect these scans. According to Biometrics Institute, a global biometrics network, iris recognition is already being used by some law enforcement and humanitarian agencies, in airports, and even for smartphone authentication.

Seeing into your retina

At the back of your eye sits the retina, which is the light-sensitive layer of tissue that converts light into electric signals, sending them to the brain where they’re interpreted as images. It’s a complex collection of blood vessels, and like our irises, is entirely unique to us. 

Unlike our irises, we can’t actually see each other’s retinas, but their incredible uniqueness means that retinal scans have an estimated error rate of only one in ten million. This far surpasses our fingerprints, with a 1/500 chance of incorrect identification. However, while retinal scans are exceptionally accurate in terms of biometric identification, they’re less practical than iris scans, requiring a more intrusive and closer imaging of the eye.

You can’t peer easily into someone else’s retinas, since they’re located at the backs of our eyes, but optometrists can! We use special drops that dilate, or open your pupil, allowing retinal digital imaging that provides us with an accurate picture of your retina. From this, we can detect multiple conditions and even gain a snapshot of what your central nervous system looks like

The process is quick and painless, but pupil dilation means that your vision will be blurry for several hours after the exam and you’ll experience increased sensitivity to light. We recommend that you bring a pair of sunglasses with you and arrange safe transport home from your exams. The effects will gradually wear off on their own.

Your eyes are like a unique piece of art

With their astonishing uniqueness, it’s easy to see why there are so many romantic notions about our eyes. They’re as beautiful and original as a one-of-a-kind piece of artwork, all our own and displayed with pride right there on our faces. They’re also exceptional communicators, from winks and eye rolls, to the ability to convey emotions ranging from an angry glare to a warm invitation. 

But it’s important to remember that their beauty is much more than skin deep. As optometrists, we’re able to gain insight into your overall health by examining your eyes. A comprehensive eye exam by a skilled optometrist offers you far more than a simple vision test (although we’ll perform this, as well). 

The Canadian Association of Optometrists encourages you to book regular comprehensive exams that can identify dry eyes, cataracts, age-related macular degeneration, diabetic retinopathy, glaucoma, and retinal detachments, among other conditions. Beyond your eye health, your optometrist is also able to detect health problems like diabetes, high blood pressure, cancers, and more.

Yes, your eyes are like a magnificent piece of art. Ensure their longevity by taking care of them, including regular examinations by a skilled optometrist like those at Dr. Sam Dhaliwal & Associates to maintain their optimal health. Come see us today.