Protect your eyes from glare
There are many types of glare that you may come across including glare in the sun, at night and in front of screens of devices. Find out what you can do to minimise the glare.
BY: Dr Lee Sao Bing
Glare is the difficulty seeing in the presence of bright light, such as direct or reflected sunlight, or artificial light such as that of car headlamps at night. An excessive amount of glare prevents a task from being completed well and can also lead to eyestrain.
Why does glare affect us more as we age?
Glare may increase as we age. There are several causes of this:
- Cataract – This is the opacity in the natural lens of the eye. When we are young, the lens is clear, however, over the years, this lens will slowly opacify and block our view. The uneven opacification of the lens will distort the light rays from entering the eye and cause an increase in glare.
- Dry eyes – The presenting symptom of dry eyes is not usually glare – symptoms of dry eyes include itchy, scratchy or burning sensation in the eyes. However, dry eyes will cause our tear film (the layer of tears at the front of our eyes) to be uneven. This will then distort the light from entering our eyes. Dry eyes occur commonly in older people. Should you experience symptoms of dry eyes, lubricate your eyes with lubricant eye drops.
- Change in refractive error (spectacle power) – A change in refractive error is not as common in adults as it is in children. But when it does increase and we are not wearing prescriptive glasses of the correct power, the focus is poor and can lead to more glare.
If you experience an increase in glare over the years, see your optometrist to check your eyes. A simple change in prescription to the appropriate pair of glasses or sunglasses may be all that is needed. If these measures do not help, the next step is to visit your eye doctor (ophthalmologist) to rule out other conditions such as cataract and dry eyes.
How do you avoid getting affected by various types of glare?
Glare while in the sun
Many of us have experienced the glare of the sun. We tend to close our eyelids in order to block out excessive light. Driving and sports (such as golf, tennis, boating and fishing) become more strenuous for the eyes particularly in the bright sun. A simple remedy to reduce this type of glare is to wear sunglasses. Choose a pair that curves to fit your face (“wraps around” your face) as this will reduce the amount of light entering through the sides.
These days there are also sunglasses that can be worn over a pair of prescriptive glasses (see right, below). These look more box-like in shape and may not appeal to those who want to look fashionable, but they serve the purpose of reducing the amount of sunlight that is entering into our eyes from the top as well as the sides.
In addition to protecting the eyes from glare, sunglasses are also vital in reducing the amount of ultra-violet (UV) light entering the eye. Excessive exposure to UV can lead to eye problems such as cataract. It is therefore vital to wear a pair of sunglasses that has 100-percent UV protection. Ask your optometrist the next time you visit the optical store for sunglasses that have good UV protection. Do note that a darker shade of sunglasses does not necessarily mean better UV protection.
Glare from sunlight reflected off shiny surfaces
Sunlight that is reflected off water or snow can be very glaring. The best type of sunglasses to reduce such glare is to use polarised sunglasses. This refers to a type of lens that can block light rays in one meridian and let in light rays of the other meridian, meaning 90 degrees to the one being blocked.
Take a look at the diagram below. Light rays come in both horizontal and vertical meridians. A polarised lens will block out the light of one meridian – the top diagram only lets in light of the vertical meridian; this same lens when turned 90 degrees will let in light of the horizontal meridian. Hold up both lenses – one held vertically and the other horizontally and stack them together – this will totally block off all light.
Polarised glasses are great when used to view reflective surfaces. They reduce the glare from such surfaces and allow a person to see better. Here are examples of some activities when polarised sunglasses will come in very useful:
- Driving on wet roads
Glare at night
The best example of such glare is those we experience while driving on a dimly-lit road with the headlamps of oncoming cars shining into our eyes. Those with high short-sightedness, high astigmatism and naturally large pupils in the dim light are more susceptible to this type of glare. Ensuring that your glasses or contact lenses are of the appropriate degree will help minimise the amount of glare. Do not compromise on safety – for those that are not comfortable with the amount of glare, it is better not to drive on dimly-lit roads.
Glare from screens of devices
With the advancement of technology, it is probable that all of us have a device in front of us for a certain length of time each day. This may be a TV, a computer screen, a laptop or a smart phone. The more time we spend staring at such screens, the more likely we are to suffer from glare if the lighting is inappropriate.
Tips for using such devices:
- Adjust the brightness and contrast till it is comfortable to your eyes.
- Always have adequate lighting in the room while using such devices.
- Turn the device away from sunlight that reflects off the screen and into your eyes.
- Do not sit too near. For example, it is good to use the computer about 50cm away.
Dr Lee Sao Bing is the medical director and principal eye surgeon at Shinagawa LASIK & Eye Centre.
(** PHOTO CREDIT: Top picture: Grandfather, kkiser, stock.xchng; rest of the pictures are provided by Dr Lee)