Between the physical risks posed by dust and grit, and the unseen damage done by ultraviolet light, there are plenty of good reasons why cyclists need to protect their eyes. Simon Frackiewicz – optometrist and orthoptist at Yeovil District Hospital and Robert Frith Optometrists – guides us through the main threats to our vision.
road.cc: Even for people who don’t require prescription lenses, are there any benefits that come with using cycling eyewear all year round?
Simon Frackiewicz: Yes, and the benefits appear on a number of different levels. Firstly, there’s obviously the eye protection element. I think people often think of cycling eyewear as being protection from the sun or ultraviolet light, but having a physical barrier in front of your eyes also helps to stop foreign objects going into the eye.
Much depends on where you’re cycling as to the types of risk you’re going to face. For example, where I go cycling in country lanes, there are lots of little particles of dust and grit on the road, which glasses protect against.
Then there are things like allergens in the air - and that would apply just as much to rural cycling as to urban cycling – which are also blocked by eyewear. Small particulate matter or pollen can go in and aggravate the eye, so having that physical protection is a good idea. It can also prevent dryness of the eyes caused by evaporation of the tear film, which can be both uncomfortable and damaging to the eye’s surface.
You can also get things like yellow tints on cycling eyewear, which is good for improving contrast and takes away some of the glare that you get from distant objects. There’s something called blue light scatter that happens with far away objects, where the short wavelength light scatters and causes blur more than long wavelength radiation. But if you have a feint yellow tint to your lenses, that instantly increases the contrast, improving your vision and making it more comfortable.
If we consider foreign bodies, what risks do they pose?
In my job I deal with a lot of foreign bodies in the eye because my practice is part of an emergency eye care programme. To quantify how much of a threat cyclists specifically face from foreign bodies in the eye is quite tricky. But there’s no doubt at all that if you’re pelting around on the road on a bike, there’s much more chance of getting things in your eye than if you’re sitting behind the wheel of a car.
But the risk really depends on what the foreign body is. If you have some organic matter like a seed husk, or even a bit of grit, that can cause quite an abrasive effect on the front of the eye. It can get stuck underneath the top eyelid, which is extremely tight against the eyeball, particularly in younger people. No matter how much you try to irrigate your eye and wash the object out, it’s effectively embedded and will just grind away at the front of the eye.
That can be exceptionally painful because the cornea - which is the transparent window in front of the eye - is actually the most sensitive part of the entire body. There are more nerves there per unit area than anywhere else on the body, which is why your eyes are so painful if you get something in them.
But there’s also the risk of picking up a metal foreign body and that can cause a lot more problems. If you get a piece of ferrous metal in the front of the eye, the eye can react quite nastily to it and you can get inflammation of the eyeball and potentially permanent scarring if it’s not dealt with appropriately.
Do contact lenses offer as much protection?
No, not really. Contact lenses are a great way to make you see better while you’re cycling and some do offer UV protection, but a lot of the physical hazards aren’t mitigated at all by wearing contact lenses. Arguably a corneal foreign body is less likely to happen but there are still other problems that can occur. Anyone with contact lenses who has been cycling around in the summer knows how horrible little black flies that can get in the eye are. Apart from just being uncomfortable, they can also cause risks to your eye health in the long term.
As you mentioned earlier, one of the other protections that cycling eyewear offers is against ultraviolet light. How damaging is UV light and what eye conditions can it cause?
Ultraviolet light is a problem all year round, not just in summer, so it’s important to protect your eyes. There are two conditions that UV is implicated in when it comes to eye health: one is cataracts and the other is age-related macular degeneration (AMD). While AMD is becoming better known, many people - particularly younger cyclists who have never had any problems with their eyes - may never have heard of it.
AMD is a degenerative condition that affects central vision and which becomes an increasing problem as we get older, but the issue can actually start quite young. There is evidence to suggest that your eyes can only take a certain number of hours of UV light exposure throughout your life before damage occurs. So, for people who spend a lot of time outside for work or hobbies, they need to be protecting their eyes from as young an age as they possibly can.
In the more common type of AMD - which is a slow degeneration – there is no cure and it leads to severe, irreversible central vision loss.
With the more rapid, wet-type of macular degeneration there is a cure, but in that case you’re having to treat leaky blood vessels in the back of the eyes and it’s not a very nice procedure. So it’s probably best not to get it in the first place!
What about cataracts, isn’t then when a film grows across the front of the eye in old people?
A lot of people don’t understand what cataracts are, and many do think that it’s a film that grows over the front of the eye. That isn’t the case.
It’s more a loss of transparency of the crystalline lens inside the eye – that’s the part of the eye that’s responsible for focusing the images at the back of the eye. The lens gradually becomes less and less transparent or opaque, and that process is more likely to happen the more exposed you are to the sun. So people who live in equatorial climates tend to get cataracts much younger than in other parts of the world.
There is another condition, though – pterygium – which is when a skin does grow across the front of the eye. It’s something that comes from the white of eye and spreads across the cornea, almost like a callus that effectively grows across the front of the eye to protect it.
You tend to see that again in people who live in very hot, dry climates. But if people are outdoors a lot – we see it more in people from the farming community or people who are always outside – then this response can also occur.
How often do you see these kinds of conditions?
In the case of cataracts and AMD, I see them every single day. They are something that most people aged 65 or older have some signs of, but the degree to which they have it is often determined by factors such as exposure to ultraviolet light. UV isn’t the one and only cause, but it is a very big factor in both those conditions.
Are there any other dangers to eyes that the public tends not to know about?
The one thing that is a huge danger, which hopefully won’t be so relevant to Road.cc readers, is smoking. People really don’t understand how damaging smoking is to the eyes. Smokers have a 10-fold increase in the risk of losing their sight compared to non-smokers.
It’s all to do with the same underlying processes that occur with ultraviolet light, which lead to free radicals in the eye. You get a lot more free radicals from smoking and they act to damage your eyes in the same way as the free radicals from ultraviolet light. It’s effectively a double whammy. A smoker who is outside in the sun a lot has a really bad prognosis in terms of their eye health.
Finally, what are your top tips for cyclists when it comes to looking after their eyes?
Keep them protected and ensure you get your eyes assessed regularly. Even if you think you can see well, there is a lot that can happen to your eyes that doesn’t affect your sight, so you should still have regular eye examinations.