What is glare?
A dictionary definition describes glare as “difficulty seeing in the presence of bright light such as direct or reflected sunlight, or artificial light such as car headlamps at night“, but just to complicate matters, did you know that there are different types of glare to consider? Ranging from mild discomfort to impairment in the ability to see and perform a task.
Types of glare
Discomfort glare from a light source or luminaire, where brightness is greater than the eye can adapt to, makes a task uncomfortable to perform. The degree of discomfort depends on several factors; the brightness and the size of the glare source, the position of the glare source in relation to the line of sight, and the background luminance against which the glare source is viewed.
Disability glare is caused by a reduction of contrast which leads to a decrease in visibility. This type of glare describes the situation when the ability to perform is adversely affected i.e. driving when the sun is low in the sky or towards a vehicle using full beam headlights. Traditionally, disability glare would be associated with incidental issues such as those described and not associated with modern lighting design practice or product technology.
How-to reduce glare
The occurrence of glare is an unwanted side effect which needs to be avoided wherever possible. With the wide use of LEDs in exterior lighting schemes, glare has become an increasingly common issue due to the small scale of LEDs as a light source, and their increased directionality.
Like with most elements associated with exterior lighting, mitigation for things like glare can and should be considered during the design stage. It is important to consider location, mounting, inclination and usage when designing a new lighting layout.
Here are some scenarios and helpful hints:
- Can glare be reduced during the design phase? Lighting design software allows for glare to be understood and specified during the design phase. Consider the use of low ‘G’ rated products or those with a low upward light output ratio. Whilst on their own the G classes do not necessarily ensure a low glare solution, they tend to reduce the risk of this occurring.
- Can glare be reduced during the installation phase? Is the design over-lighting the area? Can the effect of glare be reduced through dimming/switching when the area is not in use?
- What can be done post installation? Is a retrofit anti-glare shield available from the manufacturer? By utilising anti-glare shields, any unwanted spill lighting can be controlled and redirected.
hen light is too direct or reflected too strongly off a surface, it can produce a brighter, more dazzling light called glare. In the home, glare most frequently occurs in task lightingfixtures such as desk and table lamps, but it can occur in general lighting as well. Glare is a primary cause of eye strain, which can be uncomfortable for your eyes and result in headaches, nausea, and other unpleasant symptoms. This makes it important to reduce the amount you experience in your home. Let’s review some effective strategies for eliminating glare as a cause for eye strain.
Control Your Light Source
Perhaps the most obvious way to get a handle on glare is by controlling your light source. If you can, angle your lights so that the light isn’t shining directly into your eyes or reflecting into them off a surface. This is easy to do if you have a desk or standing lamp with a swivel feature, but if your light source isn’t multi-directional, you could also try moving your fixture to another location. For example, if your light is reflecting glare when shining directly over your desk, try placing it a little further away or even over your shoulder.
Diffuse the Light
If controlling your light is not your best option, diffusing your light can be another effective way to reduce glare. Glare often occurs because a strong concentration of light is fixed on a single place. To adequately disperse (or reduce) this concentration of light, purchase a lens cover, lamp shade, or silver bowl light bulb—whichever is most appropriate for your fixture. Lens covers are optimal for fluorescent tubes or reflectors, and silver bowl bulbs are best used in table lamps or pendant lights because of their ability to redirect light up towards the ceiling.
Change the Surface
As we’ve said before, glare can occur because light is reflecting into your eyes off a shiny surface. So, if changing your light isn’t an ideal solution, change the surface that’s reflecting the light instead.
If you are working over a desk, counter or other work space with a shiny finish, cover the surface with a table cloth, newspaper, or some other non-reflective coating while you’re working on them. If you can, purchase surfaces in a matte finish to prevent the problem. If light is bouncing off the surface of your TV or computer screen, simply turn off or dim the lights.
Glare can be annoying, but luckily it is a relatively easy problem to alleviate. Controlling your light source, diffusing the light, or changing the reflective surface are simple ways to reduce glare.
However, if you are wearing glasses, these tips may not solve your problem—you may just need new lenses. Ask your eye doctor about your anti-glare options. Sunglasses with polarized lenses are particularly helpful for eliminating glare while you’re driving, and they are available in prescription form, too.
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