Interview conducted by April Cashin-Garbutt, MA (Cantab)
Are all sunglasses made to an equal standard in terms of blocking all harmful UV rays?
All sunglasses that carry the CE mark block all UV rays, particularly if they're marked with the UV 400 label. People need to be careful that they buy sunglasses from reputable retailers, because sunglasses bought at street markets or on the beach may not carry those CE marks and may not provide the full protection element from UV light.
What’s the difference between UVA and UVB and do sunglasses need to filter both in order to keep eyes safe?
Ideally, yes. Normal lenses would filter some element of UV light.
UV light is the wavelength of light from the sun that is outside of the normal visible spectrum. That light is split into three levels: A, B, and C. Most of the C level is filtered by the ozone layer, so it doesn't really reach the earth’s surface, whereas UVA and UVB does. UVA is the longer wavelength and UVB is the shorter one.
In simplistic terms, UVA is what tans your skin and UVB is what gives you sunburn. Both wavelengths can obviously penetrate the eye, which can cause some issues. In most cases, wearing sunglasses would provide you full protection from both UV light wavelengths.
What damage can wearing tinted lenses with no protection cause to your eyes?
Clear glasses give you some level of UV protection, but just not to the full wavelength. If they're tinted, those also provide some element of protection, but not full protection. Since eyes need to be protected from the full range of UV absorption, if you are going to wear sunglasses, you may as well make sure that they provide full protection rather than partial protection.
The actual damage that occurs in the eyes involves a combination of things. Excessive absorption of UV light tends to accelerate cataract growth. It can also cause damage to the macula at the back of the eye, which can cause problems with vision.
Overexposure to direct sunlight can also cause problems with the front of the eye, leading to irritation and a burning sensation. Protection from UV light is absolutely paramount.
What are your top tips for choosing safe sunglasses?
Firstly, people should make sure they have an eye examination because if you just buy sunglasses off the shelf, without an eye examination, you would be unaware of what other issues there could be with your eyes.
It's always worthwhile to have a routine eye exam at least every two years. Following that, depending on whatever the power of the eye is, as determined by the eye examination, then the appropriate prescription sunglasses can be recommended.
That, along with the reassurance that prescription sunglasses from an optical retailer would have the full UV protection, would mean you could be in the safe knowledge that you're as protected as much as you can be from UV light, to avoid and to slow down the progress of any UV related conditions.
We take great care when we are out in the sun in terms of using sun blocks and skin lotions, but we don't have the same sort of safety in mind when we are looking after our eyes.
Who’s most at risk from sun damage? Does the color of your eyes make any difference?
There is some evidence to suggest that individuals with light colored eyes, such as blue or green, are more susceptible to absorbing more UV light because there is a lack of the pigment there would be in darker eyes.
In essence, everyone should be protecting their eyes with sunglasses and not just in the summer. Even in the winter, there's a lot of UV light about, so it should be an item of spectacle wear that we use more often.
What eye diseases are linked to UV exposure? Can these lead to vision loss?
Yes, absolutely. If they're left unattended or not addressed, then eventually, most of the conditions caused by UV light can cause issues.
One of the main ones is the accelerated growth of cataracts. Cataracts occur in most individuals, but it's the growth acceleration that's the issue. Rather than a person noticing cataracts at age 55 or 60, if a lot of UV light is absorbed throughout their lifetime and in early life, then cataracts can have an effect at a younger age. Cataracts essentially give you more of a misty, foggy vision over a period of time, although that can be easily treated.
Secondly, you may have problems with the back of your eye, in the retina and the macula. That's where the critical visual process takes place, with light being transferred into nerve signals and sent to the brain to help you actually view the images you're seeing. Any UV light damage to the skin or the retina at that point can cause some significant problems, which are a bit more difficult to treat. Those are the main problems right now.
How often should you have eye examinations?
At least every two years. There are some groups of individuals that should have an eye examination far more frequently than that, but the golden rule is every two years, unless it's recommended earlier by your optometrist.
Is it true that wearing sunglasses can help reduce the symptoms of hay fever?
There have been some suggestions of that, but it may be due to individuals wearing large, wrap-around sunglasses. That may have the effect of reducing the contact pollen makes with the eyes, rather than any hay fever relief being due to the filtration effect of the actual lenses.
Do you need to wear sunglasses all year round to protect your eyes? How do you know when you should wear them?
I think as a general rule, if it's daylight outside, then you should wear sunglasses, whether it's winter or summer. I think most of us are aware that there is UV light in the summer, but there's quite a bit of UV light about in the winter months as well, so it's quite crucial that sunglasses are worn in most daylight hours.
Where can readers find more information?
There's a wealth of information on the internet. One very good consumer website is lookafteryoureyes.org, which is hosted by the College of Optometrists. The Vision Express website also provides some information about eye health.
However, ultimately, the best piece of advice you could get that would be specific to you, would be following an eye examination with your optometrist. That's where an eye examination comes into its own because rather than giving generic information, we can examine your eyes, assess their health, and give specific information about how to make best use of your eyes and how to take care of them.
I think it's probably not prudent just to be reliant on sunglasses, without ever having an eye examination. An eye examination is a useful assessment to understand as much as possible about the health of the eyes and it can also give an indication as to a person’s general state of health.
About Omar Hassan
Omar graduated from the University of Bradford in 1999. He is currently Head of Professional Services for Vision Express and is an Optometry Advisor for NHS for Derbyshire & Nottinghamshire Area Team, where he is involved in clinical governance and commissioning eyecare services.
He has practiced as a locum in the Yorkshire area with various multiples and as a Domiciliary Optometrist. The College of Optometrists is the professional, scientific and examining body for optometry in the UK, and Omar has been a Council Member for Yorkshire and Humber, where he sat on its DOCET and Research Committee. Previously he has been actively involved in the College's Audit & Disciplinary committees.